003_[John_S_Lucas,_Paul_C_Southgate,_Craig_S_Tucker]_A(z-lib.org)

Hawaii with access to deep cold water, and hatchery Marine Finfish Aquaculture 477
facilities in Chile are under development supplied with
eggs, broodstock, and juveniles from private and govern- to improve stocking and production densities per unit of
ment entities in Canada. tank volume will be important toward reducing produc-
tion costs in intensive grow‐out systems for flatfish.
For many flatfish species, large numbers of juveniles
can be produced in hatcheries. Work is needed to reduce 20.14 ­Sturgeon
abnormal pigmentation (pseudoalbinism on the ocular
side and hypermelanosis on the blind side) and arrested Sturgeon are one of the most romanticised of fishes,
eye migration, which decrease market value. The physi- being prized for generations for their eggs in the form of
ological, environmental, and nutritional factors that reg- caviar, their meat, their skins, notochords (medicinal
ulate thyroid stimulating hormone and thyroid hormone use), and even for the isinglass derived from their swim
secretion, as well as those factors that regulate eye migra- bladders. They appear prehistoric, and are one of the
tion require investigation to enable culturists to synchro- most ancient of the living class of bony fishes, having
nise metamorphosis, settlement, and development of evolved 200 million to 250 million yr ago. Sturgeons
flatfishes in captivity. belong to the family Acipenseridae which contains
four  genera (Huso, Acipenser, Scaphirhynchus, and
Moderate growth rates from fingerling through mar- Pseudoscaphirhynchus). Nearly all sturgeon grown in
ketable stages are the main drawbacks for most cultured aquaculture are species of Huso or Acipenser, with the
flatfish species. For commercial grow‐out to be realised primary species cultured being H. dauricus (Kaluga stur-
at a significant scale, production costs need to be low- geon) or H. huso (Beluga sturgeon), A. baerii (Siberian
ered and market prices increased. In many flounder spe- sturgeon), A. gueldenstaedtii (Russian sturgeon),
cies, males grow slower after reaching sexual maturity at A. ruthenus (sterlet) and A. transmontanus (white stur-
smaller sizes and younger ages than females, and there is geon; Figure 20.16). Other species of Acipenser are also
an economic incentive to produce all‐female populations cultured to a lesser extent.
for fish farming. While genetically all‐female popula-
tions have been produced using diploid gynogenesis in 20.14.1  Biology and Life History
some flounder, these fish may still develop morphologi- Sturgeons share many anatomical characteristics with
cally as males, because phenotypic sex is influenced by sharks, such as a heterocercal tail and spiral valve in the
environmental conditions such as temperature, stocking intestine but are not truly cartilaginous as they have
density, photoperiod, tank colour, and other stressors. bones in the skull and five rows of bony plates (scutes) in
The interaction between genetic and environmental their skin. They have a physostomous (connected to the
influences on sex‐determination in flounder must be gastrointestinal tract) swim bladder as well. Sturgeons
better understood before practical methods of sex con- retain a notochord instead of bony vertebrae as the pri-
trol can be used to produce faster growing all‐female mary structural feature running through their body. All
stocks for grow‐out. Studies are needed to develop sturgeon have sensory barbels on their snout and
improved strains through selective breeding of fast‐ ­protrusible jaws making them very efficient feeders on
growing, later maturing fish or, through hybridisation.
Considering their bottom dwelling behaviour, methods

Figure 20.16  White sturgeon at the
Oregon Zoo, USA. (Photograph by
‘Cacophony’ courtesy of Wikimedia
Commons). Source: Photograph by
User: Cacophony [GFDL CC‐BY‐SA‐3.0
(http://creativecommons.org/licenses/
by‐sa/3.0/).

478 Aquaculture global production. Sturgeon production in China focuses
primarily on Siberian sturgeon, Amur sturgeon (A. schrenckii),
benthic organisms, though some larger species are also and its hybrids.
efficient at preying on other fish. Members of the
Acipenseridae are considered to be anadromous, migrat- 20.14.2.1  Culture Cycle
ing into freshwater streams or rivers to spawn. Some Broodstock sturgeon for aquaculture are rarely obtained
species remain in freshwater lakes or river systems from wild fish, and most eggs are obtained from captive
throughout their lives, while others migrate into estuar- bred populations that are multiple generations removed
ies or oceans as juveniles and remain there until matura- from the wild. In a few instances, such as with Atlantic
tion. Sturgeons tend to be relatively late maturing and sturgeon (A. oxyrhynchus) or Kaluga sturgeon, commer-
long‐lived fishes, with the oldest believed to approach cial producers release a negotiated number of small stur-
150 years of age. They also represent the largest fish spe- geon for stock enhancement in exchange for the ability to
cies found in freshwater, with a recorded size of a Beluga harvest eggs from wild fish until a broodstock can be
sturgeon from the Danube River of 7.2 m long and weigh- developed. All sturgeon are anadromous, spawning in
ing just over 1.5 t. freshwater generally in the fall or spring. The age of first
maturation for most captive‐bred sturgeon species ranges
Sturgeons are widely distributed throughout the from 4 yr (e.g., Siberian and sterlet) to over 10 yr for some
northern hemisphere above the 30th parallel, and are species (Beluga, Atlantic, and white sturgeon), depending
found along the coastal areas of the Mediterranean and on culture conditions and temperatures. Within some
Black Seas as well as the Pacific and Atlantic Oceans and sturgeon species (e.g., Russian sturgeon) different stocks
Great Lakes of North America. High concentrations of spawn in spring and others mature in the autumn.
sturgeon were historically found in the Ponto‐Caspian
basin which includes the Caspian, Azov, and Black Seas Sturgeon can be grown in captivity at elevated tem-
and their tributaries, where significant and valuable fish- peratures for faster growth until they are within 2 to 3
eries developed for these fish. Peak global capture har- years of maturation, then should be exposed to annual
vest of sturgeon occurred in 1977 at 32 078 t, followed by variation in temperature and day lengths in order to
dramatic declines in the 1980s until in 1997 all sturgeon s­ynchronise and stimulate maturation. This is true for
(and paddlefish) species worldwide were listed in the broodstock or for caviar production. Sturgeon also ben-
Convention on International Trade of Endangered efit from a period of lower winter temperatures (typically
Species (CITES) regulations to establish trade limits and 10–12 °C depending upon species) for 1–2 months to
help protect remaining stocks. induce final gonadal maturation. Unfavourable temperature
regimes have a strong, negative influence on successful
20.14.2 Aquaculture oocyte maturation and ovulation.

Sturgeons have been cultured for stock enhancement 20.14.2.2  Hatchery Practices
since the 1960s primarily in the Caspian Sea region. Sturgeon hatchery practices are described in detail in sev-
Modern aquaculture for commercial production of meat eral publications, including Conte et al., 1988, Chebanov
and caviar began in earnest in the 1980s as the wild har- and Galich, 2011, and Hochleitner and Gessner, 2012.
vests collapsed and important advances in existing stur- Briefly, in the most commonly used approach, oocytes
geon culture methods and procedures were developed are sampled from the ovaries of mature females via
and adopted. Sturgeon aquaculture then began to develop biopsy, often using a tool called a trochar, but sometimes
in countries outside the Soviet Union, with commercial using a hard plastic tube. The oocytes are boiled in saline
culture being established on a larger scale in France, or preserved with a clearing solution, then sliced along
Germany, Italy, Hungary, and on the west coast of the the animal‐vegetal pole to present a longitudinal cross‐
United States. The predominant species cultured at the section for examination under a microscope.
time included Siberian sturgeon, Russian sturgeon, ster-
let, Adriatic sturgeon (A. naccarii), Bester (hybrid of H. The state of egg maturation is determined by measur-
huso with A. ruthenus), and white sturgeon. Commercial ing the distance between the leading edge of the germi-
sturgeon aquaculture production grew from nearly zero nal vesicle (nucleus) and the animal pole of the oocyte,
in the early 1980s to approximately 5000 t by 2000. and the total distance between the animal and vegetal
poles, not including the membrane. The ratio of the for-
While continuing to expand slowly in Europe, the mer to the latter is referred to as the germinal vesicle
Americas, and countries of the Ponto‐Caspian basin, index or the polarisation index (PI). If the germinal
China began developing large‐scale production of stur- ­vesicle has already begun to degrade or breakdown or
geons around 2000, contributing substantially to the the PI is <0.05, this indicates that the oocytes and folli-
growth of sturgeon aquaculture. By 2014, reported global cles are likely to have begun breaking down, a process
aquaculture production of sturgeons had grown to nearly
90 000 t, with China’s production accounting for 85.7% of

called follicular atresia. If the PI is between 0.05 and 0.10, Marine Finfish Aquaculture 479
the fish is fully mature and can be prepared for hormonal
induction of ovulation. A PI from 0.10 to 0.12 can be together in masses, which is a normal behaviour for
induced within 2 to 3 days if the temperature is appropri- healthy sturgeon. Some culturists report that individuals
ate for spawning for the species. A PI greater than 0.12 not associated with these swarms tend to be those that
up to 0.18 will require that the fish be held for a longer are weaker or otherwise malformed. Soon thereafter
period, but may be able to spawn that season. Generally, most sturgeon become negatively phototactic and will
if the PI is greater than 0.18, the fish is too immature to move away from brightly lit areas of the tank. After 10–12
spawn that year. More precision can be derived for this days at 15 °C, the prelarval period is ending and the fish
method by adding a procedure of incubating oocytes begin to take on more of a typical sturgeon appearance.
with progesterone and evaluating the response.
Sturgeon larvae will have now developed working mouth
Final maturation and ovulation of females selected for parts and have small teeth, which they will lose quickly.
spawning can be induced using suspensions of sturgeon The opening from the mouth into their digestive tract will
or carp pituitary gland, LHRHa, or GnRHa. Males are have formed and a plug of melanin from their spiral valve
injected with approximately half the dosage of the will loosen and be released. The occurrence of this melanin
females, if needed. plug on the bottom of the tank is used by most sturgeon
culturists as a signal to begin exogenous feeding, though
In nearly all cases, sturgeon are spawned manually once not all agree with this approach. However, the extrusion of
ovulation has begun. Depending on the temperature, ovu- the melanin plugs is easy to observe as the plugs appear like
lation should occur from 12 to 48 hr following the injec- small particles of pepper in the bottom of the tanks.
tion treatments. Tanks should be checked for evidence of
females releasing eggs into the water beginning 2 hrs The next stage in the culture of sturgeon is the transi-
before the predicted ovulation time. Removal of the eggs tion of the fish to exogenous feeding, and often is associ-
from the female is complicated by the fact that the stur- ated with a peak in mortality believed to be related to
geon oviduct has a flap or ‘valve’ that prevents or limits abnormalities in morphological development. These
manual stripping. Eggs are typically removed by caesarean abnormalities may be related to culture conditions,
section or by making a small incision in the oviduct just maternal nutrition, or simply be hereditary in nature.
inside and anterior to the vent opening. Sperm is collected Depending on the species, the larval sturgeon at this age
from the males using a large syringe connected to a cath- will weigh from 20–50 mg. Beluga sturgeon tend to be
eter or tube inserted into the vent opening. The sperm can somewhat larger weighing up to 70 mg. Some species of
be stored in the syringe at 4 °C for 2 or more days, so this sturgeon, especially larger sturgeon such as Beluga,
can be collected in advance of egg collection. As sturgeon Russian, or white sturgeon may tend to become canni-
eggs have multiple micropyles, the sperm should be balistic in the initial phases of feeding.
diluted at the time of use to prevent polyspermy.
Sturgeon larvae do not require live feeds at the initial
Fertilisation is done by mixing sperm diluted with stages of feeding, however most culturists will offer live
water (1:200) with eggs for 1–3 min or until the eggs feeds due to the higher success rate obtained with this
begin to become adhesive. A solution of water and silt, method. Live feeds offered included Artemia nauplii,
Fuller’s earth, talcum powder or other suitable material small cladocerans, copepods, and sometimes amphi-
is then added to the eggs and mixed for 30–60 min until pods, midge larvae, tubifex, or other small oligochaetes.
the eggs no longer stick together. Eggs are washed with The duration of offering live feeds will depend on the
fresh water, enumerated and incubated in upwell incuba- species and the plans for further grow‐out. If the fish are
tors until hatching. Hatching times vary with species, but to be transitioned to prepared diets, suitable micropel-
on average sturgeon will hatch in 6–7 days at 15 °C. lets should be offered along with the live food as soon as
feeding is observed in the majority of the larvae, typically
20.14.2.3  Fingerling Production within 3 to 4 days. Following 10 to 14 days of live/mixed
Sturgeon hatch at a stage called a prelarvae, which lasts feeding, the live feeds may be discontinued and the fish
until the fish begin exogenous feeding. For most species, should feed well on the prepared diet if it is palatable. By
this stage will last 1 to 1.5 times as long as the time from this time, the fish will be about four times their initial
fertilisation until hatching. During this phase, sturgeon weight upon first feeding. For sturgeon that are to be
develop their sensory and internal organs, mouth and gill grown in tank systems, the small sturgeon will be ready
structures, barbels, scutes, skin and subterminal mouths. for stocking into grow‐out tanks after 60 to 90 days,
Upon hatching sturgeon tend to be positively phototactic, depending on the type of tank and configuration used.
swimming up toward light then drifting down. Initially,
sturgeon will disperse throughout the tanks with infre- 20.14.2.4 Grow‐out
quent swimming. After 2–4 days, they begin to cluster In Europe and North America, nearly all sturgeon aquacul-
ture is done in tank systems (Figure 20.17), largely due to
the regulatory limits on culturing non‐native species of

480 Aquaculture

Figure 20.17  White sturgeon raised for caviar in outdoor flow‐through tanks in California, USA. Source: USDA NRCS 2011. Reproduced
under the terms of the Creative Commons Attributions license, CC‐BY 2, via Flickr.

sturgeon. In South America and Asia, particularly in China, ever this may not be true for all sturgeon species, and the
most of the sturgeon production takes place in impound- impact on liver function is still a matter of debate.
ments in net pens, in ponds, or other open water systems.
Rearing densities for sturgeon in tanks or other high‐den- Sturgeons are grown for caviar and for their meat, but the
sity systems are largely determined by available oxygen, primary economic motivation for commercial sturgeon
concentration of metabolites, and the ability to efficiently production is for caviar. Interestingly, sturgeons tend to
feed the fish. Sturgeons are benthic‐oriented fishes, so a accumulate certain fatty acids in the caviar, somewhat irre-
primary difference in considering the approach to stur- spective of dietary levels. Though not the highest in con-
geon culture is to consider the bottom surface area, par- centration in caviar, several unsaturated fatty acids including
ticularly in tanks. For sturgeon larger than 1 kg, densities of oleic acid, DHA, and EPA tend to be accumulated at levels
60 to 100 kg/m3 have been reached in tank systems with disproportionate to the dietary intake. Optimal ratios and
suitable capabilities for maintaining water quality and oxy- dietary levels for these highly unsaturated fatty acids and
gen availability. Net pen or cage culture of sturgeon may their impacts on caviar production are still the subject of
require the fish to be trained to efficiently consume a float- considerable research on sturgeon nutrition.
ing feed. Sturgeon can be grown to market size for foodfish
(2.0 to 2.5 kg) in about 1.5 yr in intensive systems, but the 20.14.2.6  Gender Identification Challenges
markets for that size fish are primarily in Russia and China. The primary economic value of sturgeon in commercial
European and American markets for sturgeon are typically aquaculture results from the harvest of caviar. Unfortunately,
seeking larger fish, from 5.0 to >10.0 kg. sturgeons do not exhibit external sexual dimorphism until
they are fully mature, making it nearly impossible to deter-
20.14.2.5  Nutrition and Feeds mine whether the animals are male or female from visual
Dietary requirements for sturgeons are not well known, examination. Since no genetic marker for gender has to date
though they grow well on diets developed for salmonids been identified in sturgeons, g­ ender identification has his-
and these are often used in aquaculture. Typical sturgeon torically been done with varying success using endoscopy,
diets are high in protein (40–50%) and moderate in lipid gonad biopsy, ­borescope, blood sampling for biomarkers
(9–16%). The specific amino acid requirements for stur- such as sex steroids or neuropeptides, and examination of
geon are also yet to be precisely delineated. High levels of the urogenital pore and other anatomical features. Females
digestible carbohydrates have been suggested to adversely with late stage vitellogenic eggs (close to harvest) exhibit a
affect liver function and metabolism of sturgeons, how- swollen belly and enlarged girth, but males are difficult to
distinguish from immature and non‐vitellogenic females

when relying on gross examination unless milt is flowing. Marine Finfish Aquaculture 481
The shape of the urogenital opening of fully mature stur-
geon has been suggested as a means to identify gender planktonic foods during their larval stages. Three feed
dependent on species but this technique has not been types are common in marine larval fish culture: micro-
proven in immature fish. Other noninvasive techniques algae, rotifers, and Artemia. To reduce production
such as ultrasound have shown some limited success in costs, artificial diets are increasingly used to substitute
determining gender of immature sturgeon, but can be for expensive live prey.
applied with greater success once the animals are fully ●● Grow‐out systems for marine finfish include shallow
mature or reach at least a minimum stage of maturity. coastal ponds, coastal pens, offshore cages, land‐based
flow‐through, and recirculating aquaculture systems.
More accurate gender determination has been accom- Pen and cage systems face unique ecological, environ-
plished via surgical means such as endoscopy but even with mental, and engineering challenges.
endoscopy, gonad biopsy may be required for gender confir- ●● Most marine fish in aquaculture are carnivorous and require
mation. Other techniques, such as genomic analyses or use high‐energy, high‐protein aquafeeds that usually contain
of expressed biomarkers for gender have not yet been shown substantial amounts of fishmeal and fish oil. A major
to be discriminatory for sturgeon gender and would require challenge for the marine finfish aquaculture industry is
expensive analyses impractical for on‐farm use. In current to continue to reduce its dependence on wild fish for feeds.
practice in commercial sturgeon aquaculture systems, juve- ●● More milkfish are grown than any other marine fish
nile sturgeons are typically grown until approximately 24–36 except salmon, with total production exceeding 1 mil-
months of age or older. At that time or subsequently, gender lion t in 2014. The euryhaline and omnivorous milk-
is typically identified using either direct observation of the fish can be farmed in a variety of culture systems
gonad with endoscopy, biopsy, or with ultrasound. including inland brackish water ponds, fish pens and
cages situated in freshwater lakes and reservoirs or in
20.14.2.7  Harvest and Processing coastal estuarine and marine environments.
Whether harvested for caviar and meat (females) or just ●● European seabass were historically cultured using wild
meat (males), the entire fish is harvested in nearly all cases. seedstock in coastal lagoons with other species, including
Since caviar is expected and defined to be the unfertilised gilthead sea bream and mullet. Hatchery technologies
eggs (oocytes) removed from the ovarian tissues (follicles) developed in the late 1970s allowed commercial‐scale
of sturgeon, non‐lethal means of harvest are expensive farming. Most seabass are grown in sea cages and impor-
and slow. Surgical and hormonal applications can be used tant farming countries are Turkey, Greece, Spain, and Egypt.
to remove the ovaries from mature sturgeon or to force ●● Gilthead sea bream have been cultivated for centuries
ovulation, respectively. These approaches are rarely used in Italy based on wild‐caught seed. Availability of
in commercial sturgeon aquaculture. hatchery‐produced juveniles led to large‐scale aqua-
culture production in sea cages by the late 1980s.
Many parts of sturgeons have significant value including Gilthead sea bream are usually grown in cages, with
those previously mentioned: skins, swim bladders, noto- production in Greece, Turkey, Egypt, and Spain.
chord, and even the testes have value as ‘white caviar.’ ●● Yellowtail amberjack culture is the largest marine fish
Sturgeon meat is often marketed as fillets, ‘bullets’ (headed, farming industry in Japan, where fish are cultured in
gutted and finned), or the fish are sold whole. Smoked stur- floating sea cages in nearshore coastal waters. Although
geon is also a highly valued product and considered a deli- artificial propagation of Japanese amberjacks in captiv-
cacy in many regions. Caviar is made from the harvest of ity has been achieved, a ­majority of fry for stocking sea
the entire ovary of the mature female and can represent an cages are obtained by capture of wild fry.
average of 15% or more of the body weight of the fish. The ●● Red sea bream is the second largest fish culture indus-
egg size, commonly called ‘bead size’ when referring to cav- try in Japan after yellowtail amberjack. It is grown from
iar, ranges from 1.8 mm for sterlet up to 4.5 mm for Beluga. hatchery‐produced juveniles in nearshore sea cages.
●● Cobia has become an important cultivated marine
20.15 ­Summary ­finfish within the last 20 years. Hatchery‐produced
fingerlings are grown to marketable sizes in sea cages
●● More than 90 species from 34 families of fish are grown or pens in nearshore or in offshore locations. China
in marine aquaculture. In 2014, world aquaculture pro- produces almost 90% of farmed cobia.
duction of marine finfish (excluding salmon) was 3.37 ●● Flatfish are demersal fish found in all of the world’s
million t, or 7.3% of total fish production, but it repre- oceans. The group includes flounders, turbot, soles,
sented 14% of the total value of world finfish production. and halibut—all important food fish. The unique char-
acteristic is the metamorphosis from symmetric larvae
●● Production of seedstock is a continuing bottleneck in to asymmetric juveniles and adults with both eyes
farming many marine fish species due to their special lying on one side of the head. The demersal habit poses
requirements for captive spawning and for living unique challenges for culture.

482 Aquaculture geon are produced in net pens, in ponds, or other
open water systems. In Europe and North America,
●● Sturgeon are farmed mainly for their eggs in the more sturgeon are produced in tank systems due to
form of caviar, but their meat, their skins, noto- the regulatory limits on culturing non‐native species
chords (medicinal use), and swim bladders (isin- of sturgeon.
glass) are also of significant value. China accounts
for almost 90% of global production. In China, stur-

R­ eferences Koshio, S. (2002). Red sea bream, Pagrus major. In: Webster,
C. D. & Lin, C. E. (Eds.) Nutrient Requirements and Feeding
Alam, M. S., Teshima, S., Yaniharto, D. et al. (2005). of Finfish for Aquaculture. CAB International, Wallingford.
Assessment of reference amino acid pattern for diet of
juvenile red sea bream, Pagrus major. Aquaculture Kousoulaki, K., Saether, B.‐S., Albrektsen, S. et al. (2015).
International, 13, 369–379. Review on European sea bass (Dicentrarchus labrax,
Linnaeus, 1758) nutrition and feed management: a
Alam, M. S., Watanabe, W. O., Myers, A. R. et al. (2011). practical guide for optimising feed formulation and
Effects of replacement of menhaden fish meal protein by farming protocols. Aquaculture Nutrition, 21, 129–151.
solvent extracted soybean meal protein supplemented
with or without L-methionine and L-lysine on growth Koven, W. (2002). Gilt‐head sea bream. In: Webster, C. D.
performance and body composition of juvenile southern & Lin, C. E. (Eds.) Nutrient Requirements and Feeding of
flounder. North American Journal of Aquaculture, 73, Finfish for Aquaculture. CAB International, Wallingford.
350–359.
Lee, C‐S. (1995). Aquaculture of milkfish. Tungkang
Benetti, D., Sardenberg, B., Hoenig, R., et al. (2010). Cobia Marine Laboratory Aquaculture Series, 1. Tungkang
(Rachycentron canadum) hatchery‐to‐market Marine Laboratory, TFRI, Taiwan, and The Oceanic
aquaculture technology: recent advances at the Institute, Hawaii, USA. 141 pp.
University of Miami Experimental hatchery (UMEH).
Revista Brasileira de Zootecnia, 39, 60–67. Liao, I. C., Leano. (Eds.) (2010). Milkfish Aquaculture in
Asia. World Aquaculture Society, Baton Rouge.
Bronzi, P., Rosenthal, H, and Gessner, J. (2011). Global
sturgeon aquaculture production: an overview. Journal Moksness, E., Kjorsvik, E. and Olsen, Y. (Eds.) (2004). Culture
of Applied Ichthyology, 27, 169–175. of Cold‐Water Marine Fish. Wiley Blackwell, Oxford.

Chebanov, M. and Galich, E. (2011). Sturgeon Hatchery Nakada, M. (2002). Yellowtail culture development and
Manual. FAO Fisheries and Aquaculture Technical solutions for the future. Reviews in Fisheries Science, 10,
Paper 558, Food and Agriculture Organisation of the 559–575.
United Nations, Ankara, Turkey.
Nguyen, H. P., Khaoian, P., Fukada, H. et al. (2015). Feeding
Conte, F. S., Doroshov, S. I., Lutes, P. B. et al. (1988). Hatchery fermented soybean meal diet supplemented with taurine
Manual for the White Sturgeon Acipenser transmontanus to yellowtail Seriola quinqueradiata affects growth
Richardson with Application to Other North American performance and lipid digestion. Aquaculture Research,
Acipenseridae. University of California Press, Oakland. 46, 1101–1110.

Daniels, H. V. and Watanabe, W. O. (Eds.) (2010). Practical Pavlidas, M.A. and Mylonas, C. C. (Eds.). (2011). Sparidae:
Flatfish Culture and Stock Enhancement. Wiley Biology and Culture of Gilhead Sea Bream and Others.
Blackwell, Oxford. Wiley Blackwell, Oxford.

Hochleithner, M. and Gessner, J. (2012). The Sturgeons and Q. de Bezerra, T., Domingues, E.C., Maia Filho, L. et al.
Paddlefishes of the World—Biology and Aquaculture, 3rd (2016). Economic analysis of cobia (Rachycentron
edition. AquaTech Publications, Kitzbuehel. canadum) cage culture in large‐ and small‐scale
production systems in Brazil. Aquaculture International,
Kader, M. A., Bulbul, M., Koshio, S. et al. (2012). Effect of 24, 609–622.
complete replacement of fishmeal by dehulled soybean meal
with crude attractants supplementation in diets for red sea Sicuro, B. and Luzzana, U. (2016). The state of Seriola spp.
bream, Pagrus major. Aquaculture, 350–353, 109–116. Other than yellowtail (S. quinqueradiata) farming in the
world. Reviews in Fisheries Science & Aquaculture, 24,
Kaushik, S. J. (2002). European Sea Bass, Dicentrarchus 314–325.
labrax. In: Webster, C. D. & Lin, C. E. (Eds.) Nutrient
Requirements and Feeding of Finfish for Aquaculture. Tacon, A. G. J., Hasan, M. R. and Metian, M. (2011).
CAB International, Wallingford. Demand and Supply of Feed Ingredients for Farmed Fish
and Crustaceans: Trends and Prospects. FAO Fisheries
Kawato, Y., Ito, T., Kamaishi, T. et al. (2016). Development of and Aquaculture Technical Paper No. 564. Food and
red sea bream iridovirus concentration method in Agriculture Organisation of the United Nations. Rome.
seawater by iron flocculation. Aquaculture, 450, 308–312.
Tucker, J. (1998). Marine Fish Culture. Kluwer, Dordrecht.
Kitada S. and Kishino H. (2006). Lessons learned from Vasquez, F. J. S. and Mũnoz‐Cueto, J. A. (Eds.) (2014).
Japanese marine finfish stock enhancement
programmes. Fish Research, 80, 101–112. Biology of European Sea Bass. CRC Press, Boca Raton.

483

21

Soft‐shelled Turtles

Qingjun Shao and John S. Lucas

CHAPTER MENU 21.7 Nutrition, Feeding and Feed Formulation,  491
21.1  Introduction, 483 21.8 Infectious Diseases,  493
21.2  Biology, 483 21.9 Harvesting and Processing,  494
21.3  Aquaculture Development,  485 21.10 The Future of Soft‐Shelled Turtle Farming,  495
21.4  Culture Facilities,  486 21.11 Summary, 496
21.5  Culture Stages,  488
21.6  Water Quality,  490 References, 496

21.1 ­Introduction It has been introduced to Malaysia, Singapore, Thailand,
Philippines, Timor, Batan Islands, Guam, Hawaiian
The Chinese soft‐shelled turtle, Pelodiscus sinensis, is a Islands and mainland USA.
high‐valued species for farming in the Asia region
(Figure 21.1). Traditionally, the soft‐shelled turtle is con­ Another soft‐shelled turtle, Palea steindachneri, is
sidered to have medicinal properties due to its high listed in Appendix III of the CITES Convention and as an
nutritional value. As well as its food value, it was cultured Endangered Species in the IUCN Red List (2007).
in common carp ponds in order to control fish stocking Farming has considerably impacted the wild populations
density. This is according to the first record in aquacul­ but farming of Palea steindachneri continues in China.
ture history by aquaculturist Mr. Fan Li in ‘Fish Farming
Experiences’, more than 2400 years ago (Ling, 1977). 21.2.1  Morphology and Physiology
Soft‐shelled turtles do not have the usual hard, fused
21.2 ­Biology plates that make up the carapace (shell) of most turtles.
The central part of their carapace has solid bone beneath
The Chinese soft‐shelled turtle, Pelodiscus sinensis (also it like other turtles, but its surface is leathery and espe­
known as Trionyx sinensis), has the colloquial names, cially flexible along the sides, which are known as ‘skirts’.
Zhong‐hua‐bie, Jia‐yu (shelled fish, with ‘shell’ bone) These are clearly evident in Figure 21.1.
and Wang‐ba in Chinese. In Mainland China, there are
two genera and six species of soft‐shelled turtles (Family Chinese soft‐shelled turtles are amphibious, and they
Trionychidae). The two genera are: Pelodiscus and usually live in salinities of not more than 3–5‰. They
Palea. The widespread distribution of Pelodiscus sinen- prefer the secluded regions of a wide range of aquatic
sis in China even includes Qinghai, Xinjiang and Tibet in environments, rivers, lakes, reservoirs, ponds, pools and
north‐western parts of China. Furthermore, farming mountain streams, where they inhabit the shore sub­
this species has spread to all provinces and autonomous strates and bushes. They are belligerent, aggressive and
regions in China. Beyond mainland China, this species predatory, but sensitive to the movement of objects and
is distributed in Taiwan, Japan, Korea and Vietnam1. other kinds of animals in their vicinity. Their lungs are
used for respiration both on land and in the water, as
1  See also http://www.fao.org/fishery/culturedspecies/Trionyx_ they rise to breathe. They also use a pharyngeal organ
sinensis/en (accessed November 2016) with villi‐like gills to get oxygen from the ambient water,
especially when immersed during their hibernation.

Aquaculture: Farming Aquatic Animals and Plants, Third Edition. Edited by John S. Lucas, Paul C. Southgate and Craig S. Tucker.
© 2019 John Wiley & Sons Ltd. Published 2019 by John Wiley & Sons Ltd.

484 Aquaculture 21.2.2 Diet
Soft‐shelled turtles are voracious feeders and omnivo­
Figure 21.1  The Chinese soft‐shelled turtle, Pelodiscus sinensis. rous, but high‐protein animal food is favoured. In the
Source: V. Menkov 2009. Reproduced under the terms of the wild, juvenile soft‐shelled turtles search for large zoo­
Creative Commons Attributions license, CC‐BY‐SA 3.0. plankters, aquatic insects and other invertebrates, such
as aquatic worms (Limnodrilus hoffeisteri), and inverte­
As reptiles, their body temperature varies and is simi­ brate larvae as their food. As juveniles grow, they begin
lar to their immediate environment. Thus, they are to prey on shrimp, tadpoles and small fish. When animal
s­ ensitive to variations in water temperature. Their meta­ food is short, they will feed on aquatic and terrestrial
bolic rate declines sharply when the water temperature plants, and scavenge on animal carcasses. In farming
drops below 20°C. They stop feeding at temperatures conditions, they are fed on high‐quality artificial feeds,
below 15°C and hibernate under pond mud or in wet soil internal organs of poultry, small fish, shrimp, snails and
above the pond water level when the temperature is clams, depending on the farming method. Plant feeds
below 10°C. When the water temperature is above 35°C such as various seeds, melons, vegetables, and leaves of
in summer, the turtles retreat under the shade of trees. aquatic and terrestrial plants may be used as supplemen­
The suitable temperature range for the turtle’s growth is tary feeds when necessary.
about 20–35°C and the water temperature for optimum
growth is 28–32°C, especially in indoor culture. Although soft‐shelled turtles can survive for a long
period without any feed, their growth is inhibited, and
During hibernation, there is little respiration and a body weight reduced under such conditions. Excessive
very low metabolic rate. The lungs respiratory function culture density or food shortage will cause cannibalism.
is replaced by the pharyngeal villi for getting oxygen in This especially occurs when various sizes of soft‐shelled
water or in wet sands. After hibernating for 5–6 months turtles are cultured together: the small individuals may
over winter, the body weight is reduced by 10–15%, and be eaten by the large ones. Also, the small turtles often
some physically vulnerable turtles may die during a long cannot get enough feed for normal growth under these
period of hibernation; that is, especially when hibernat­ competitive conditions.
ing in anoxic conditions under mud with high organic
matter content. 21.2.3 Growth
The growth of soft‐shelled turtles is relatively slow in the
Soft‐shelled turtles usually emerge from the water and wild. The hibernation period lasts about half a year in the
bask for 2– 3 h/day on sunny days in summer to kill sur­ Yangtze River Basin regions, and the growth period is
face pathogens, e.g., fungi and bacteria. This helps to not more than 6 mo each year because the water tem­
promote shell growth, and body calcium and phospho­ perature is unfavourable, being less than 25°C. In the
rus metabolism. It also increases their body temperature wild, it usually takes 4–5 years for turtles to reach mar­
and metabolic rate if the water temperature is not high ketable size in Yangtze River Basin regions. However,
enough for good growth. So, it is very necessary to have under artificial farming conditions where water temper­
5–10% land beside an earthen pond for basking or to ature is kept about 30°C, with good water quality and
build a similar amount of accessible basking roof above artificial feeds, the turtles grow rapidly and may reach a
water level. commercial size of about 400 g in 8–12 mo.

Like many other cultured animals, the growth rates of
soft‐shelled turtle within the same batch of juveniles
under the same conditions vary from individual to indi­
vidual. This can lead to cannibalism and they need to be
sorted and cultured in size classes during artificial cul­
ture conditions.

21.2.4 Reproduction
Reproduction follows a typical reptilian pattern. The
male fertilizes the female through copulation. Eggs are
fertilized in the female’s reproductive system, develop­
ing internally for 10–20 days and then being laid to

hatch later. Soft‐shelled turtles reach sexual maturity in Soft‐shelled Turtles 485
the wild:
21.3 ­Aquaculture Development
●● at about six years of age in the north of the Yellow River
(ca. 37°N); As well as extensive and polyculture, intensive farming of
soft‐shelled turtles in China can be traced back to the
●● at about four years in the middle and lower Yangtze late 1970s. Furthermore, the development of intensive
River region (ca. 32°N); farming may be divided into three phases:
1) The first phase of modern development was from the
●● at three years in the south of China;
●● at just two years of age in Hainan (ca. 19°N) and Taiwan mid‐1970s to the early 1990s. In this phase, the farming
of soft‐shelled turtles depended mainly on wild‐caught
(ca. 23°N). turtles. Soft‐shelled turtles were farmed at low density
in polyculture ponds and production was very limited.
These differences result from the temperature regime 2) The second phase was from the early to mid‐1990s. It
during the turtles’ growth and development. A further was a period of rapid development (Figure 21.2). With
effect of temperature regimes between northern and the improvement of people’s living standards and higher
southern China is variation in the duration of the ovipo­ incomes, the demand for soft‐shelled turtles increased
sition period. It is from: rapidly in Chinese coastal regions and bigger cities. At
the same time, aquaculture technology developed into
●● June to August in the most northern regions of China; intensive monoculture indoors in an environment with
●● May to August in central and eastern China; water temperature controlled around 28°C to 32°C.
●● April to September in southern regions of China; and Stocking density significantly improved with about
●● March to October in the Hainan and Taiwan islands. 40–80 turtles/m2 from hatchlings up to body weight 50
g and about 15–30 turtles/m2 for body weights greater
Temperature also plays a role in mating: in the middle than 150 g. The price of the soft‐shelled turtles increased
and lower Yangtze River regions, the sexually mature to 580 CNY/kg (ca.‐ USD 85). Hatchlings were 30–35
turtles mate when water temperature increases to about CNY each and the price of broodstock reached more
20°C in April or May. than 1000 CNY/kg in Zhejiang Province, which was one
of the major regions for soft‐shelled turtles. Driven by
With day‐length and temperature increasing, females high profits, various regions entered the turtle c­ ulture
gradually begin laying eggs as spring turns into summer. industry, promoting the rapid development of soft‐
The female turtles lay eggs two or three weeks after mat­ shelled turtle farming.
ing. Eggs are usually laid at night when the surroundings
are quiet. Laying sites are usually concealed places and 400
eggs are buried in moist soft soil above the water level. In
order to prevent direct sunlight, reduce evaporation, 300
avoid groundwater flooding and maintain enough air in
the nest, turtles make their individual burrows in shady Production (103 t/yr) 200
places. They put sand back over the burrow with their
hind limbs and smooth the surface flat with their plas­ 100
tron (under surface of carapace) to erase traces of the
burrow and prevent pests from invading it. The hatch­ 0 2000 2005 2010 2015
lings emerge from the burrow and move immediately 1995
down into the nearby water.
Figure 21.2  Annual production of soft‐shelled turtles, Pelodiscus
About 20 days later, the turtles mate again after previ­ sinensis, in China over the period 1994–2014. Source: Data from
ous egg laying. Adults can mate several times during FAO 2015. Source: Reproduced with permission from John Lucas.
breeding seasons each year or there can be multiple egg
batches after one mating. Sperm can survive in the
female’s fallopian tubes for five or more months. While
soft‐shelled turtles lay eggs several times a year, the
number of eggs per batch, the timing of laying, the num­
ber of egg batches and the egg weight are directly related
to the female’s body size, age, nutritional status, geo­
graphic location and genetics, etc. Approximate num­
bers of eggs per batch range from several to more than
20, and 3–5 batches of eggs may be produced in a year by
a female turtle.

486 Aquaculture Guangdong and Guangxi. Large‐scale indoor culture of
6 soft‐shelled turtles on an intensive scale started in the
1990s as described in section 21.3. Expansion was mainly
Market value (USD/kg) 5 stimulated by high profits with:
●● significantly reduced culture time;
4 ●● lower prices of hatchlings; and
●● development of feed and culture technology.
3 2000 2005 2010
1995 Local markets remained the outlet for all productions
since the incomes of the people in these two basins were
Figure 21.3  Value per kg of soft‐shelled turtles, Pelodiscus sinensis, higher than other regions in Mainland China. Total produc­
in China over the period 1994–2014. Source: Data from FAO 2015. tion in mainland China since 1995 is shown in Figure 21.2.
Source: Reproduced with permission from John Lucas.
In recent years, the province of greatest soft‐shelled
3) The third phase is from the mid‐1990s to the present. It turtle production in China has been the Zhejiang
is a continuing phase of rapid development (Figure 21.2). Province, which is located in the south of Shanghai and
Due, however, to uneven quality and taste of meat, near Lake Taihu. The Great Canal of Beijing extending to
overproduction and steadying of market demand, Hangzhou and the Qiangtang River crosses the province.
prices declined (Figure  21.3). Farming methods Based on estimation from Zhejiang Bureau of Ocean and
changed from the second phase of high‐density indoor Fisheries, the total amount of soft‐shelled turtle produc­
or outdoor monoculture or both, to lower stocking tion in Zhejiang Province in 2008 was 110 000–120 000 t
densities together with an increasing level of fish and (about 52% of the total soft‐shelled turtle production in
turtle polyculture. With further improvement of farm­ Mainland China). In terms of marketing, there were
ing techniques such as disease prevention, strains and about 41 000 t from Jiaxin City, 27 500 t from Hangzhou
hybrid selection, the production and demand for soft‐ City, 22 000 t from Huzhou City and 5200 t from Jinhua
shelled turtles in mainland China were almost bal­ City. The total value was about 5 billion CNY. The total
anced. Farming techniques tended to mature, and it culture pond area is about 7300 ha (730 million m2), and
was almost the most profitable aquaculture practice in the total area of indoor tank culture with temperature
China, so that soft‐shelled turtle farming in indoor control is about 7.5 million m2.
dark tanks and outdoor earthen ponds was continu­
ously developed, and more and more companies and 21.4 ­Culture Facilities
businesspeople invested in the turtle farming.
The culture methods for soft‐shelled turtles consist
Production techniques are well‐developed and compare mainly of outdoor earthen ponds, indoor concrete tanks,
favourably with those developed for many other aqua­ and a combination of both through the phases of devel­
cultured species in mainland China. opment. The quality of turtles cultured indoors in con­
crete tanks is lower than those from earthen pond
21.3.1  Commercial Farming culture, and pharmaceuticals are used more frequently
Traditionally, soft‐shelled turtles supplied in markets were to prevent diseases in indoor culture. However, the
fished from local ponds, reservoir, rivers and lakes. The period of rearing to marketable size is shorter and the
regional popularity of the turtle stimulated interest in pond costs per kg of turtle produced are lower for indoor cul­
culture in the early 1950s and 1960s. In the early 1980s, ture. Thus, indoor culture is attractive as a more eco­
soft‐shelled turtles in ponds were popular in the Yangtze nomic industry. Currently, indoor cultured turtles
Basin areas and the Pearl Basin areas including the prov­ account for more than half of the total production.
inces of Zhejiang, Hunan, Hubei, Jiangxi, Jiangsu, Anhui,
21.4.1  Indoor Culture
The construction of indoor concrete tanks must meet
the environmental requirements of soft‐shelled turtles.
They must have good insulation properties and be
equipped with appropriate heating, aeration, drainage
and other facilities. The tanks are 15–45 m2 of bottom
area and 60–120 cm height. The upper tank walls curve
inwards 8–10 cm to prevent the turtles from escaping.

Soft‐shelled Turtles 487
Table 21.1  Recommended stocking densities of Chinese soft‐shelled
turtles in earthen ponds.

Body weigh (g) Stocking density in Suitable earthen
earthen ponds (no./m2) pond sizes (m2)
4 –50
51–150 6–12 50–100
>150 3–6 500–1500
Broodstock 1–2 500–5000
0.5–1 1000–15 000

Figure 21.4  Netting bags that are used to provide cover in indoor about 5–10% of pond water area for the turtles to bask
tanks for soft‐shelled turtles. Source: Reproduced with permission during the daytime. The height of escape‐proof walls
from Qingjun Shao. must be 40–50‐cm. Particular attention is needed for the
water outlet and inlet to prevent turtles escaping.
Net bags are suspended above the bottom of the tanks in
order to add hiding places and so reduce the level of bit­ The stocking density depends on turtle size or body
ing at high stocking densities. Net bags being used in weight, pond depth, and how much yield the producer
indoor tanks are shown in Figure  21.4. Culture in the hopes to gain. Suggested stocking densities of turtles are
dark also assists in reducing the level of biting. shown in Table 21.1.

Progressively more farms are using temperature‐ Turtles are stocked in grow‐out ponds when water
controlled indoor tanks to rear the soft‐shelled hatch­ temperature reaches about 25°C, from March to May,
lings up to 50–150 g then transfer them to earthen ponds and the optimal body weight of turtles is 150–250 g.
for subsequent grow out. In this way juveniles are initially Before stocking, turtles are disinfected with 3% salt water
cultivated in controlled conditions to improve growth or 20 mg/L potassium permanganate for 5–10 min.
and survival rates. This is a two‐stage method of culture. Various kinds of ponds are built with an escape‐preven­
tion structure or enclosure in order to confine the turtles
21.4.2  Pond Culture (Figure 21.5).
Pond culture of soft‐shelled turtles includes monocul­
ture, and polyculture with fish, shrimp and aquatic plants. In order to have good pond water quality, the soft‐
The quality of the soft‐shelled turtles cultured in this way shelled turtles are polycultured with other aquatic ani­
is quite similar to that of wild turtles and is much better mals such as filter‐feeding fish and bottom feeders; and
than those cultured indoor in dark tanks. Furthermore, aquatic plants such as water hyacinth (Eichhornia cras-
this culture method also improves the usage of water, sipes) and water lettuce (Pistia stratiotes). In general, in
with less water exchange and less energy required to sup­ order to avoid fish taking the turtles’ feed, feeding sites
ply water to the culture system. The farmer’s income will are established near the pond water level. Feeding sites
increase when prices for pond‐reared turtles are higher. are shown in Figure 21.5. In order to control small feral
fish, some carnivorous species of fish, such as mandarin
Typical pond preparation is required before stocking fish, may be stocked at the same time. The stocking den­
the turtles in earthen ponds. This includes preparation sities of the fish are based on what natural food sources
such as: are available in the ponds and the suggested numbers are
●● clearing surplus silt listed in Table 21.2.
●● checking the water inlet and outlet
●● building escape‐proof walls In the process of culture, it is necessary to pay consid­
●● disinfecting the pond with quicklime erable attention to management of water quality and dis­
Water must be kept 1.0–2.0 m in depth, with 10–25 cm ease prevention. There is no need to set up aerating
bottom sludge, and the slope of the pond walls must be machines in ponds because the various species in poly­
45° or less. It is necessary to keep the dry land or platform culture are feeding in their niches at a reasonable nutri­
tional level without major inputs of feed. Water quality is
maintained within the requirements of pH 7–8, total
alkalinity 0.5–3.5 mmol/L, transparency 25–35 cm, and
water colour of yellow‐green or tea green. Quicklime or
biological agents are used to regulate the water quality
every 15–20 days if the water is too fertile. Diseases
are common in ponds and there may be regular use of
quicklime or a mixture of copper sulphate and ferrous

488 Aquaculture

Figure 21.5  The edge of a pond with walls to prevent turtles from escaping and with feeding sites for placing food along the slope above
the water level, out of reach of fish. Source: Reproduced with permission from Qingjun Shao.

Table 21.2  Recommended stocking densities of various fish the application of quicklime or bleaching powder (chlo­
species polycultured in earthen ponds with Chinese soft‐shelled rine) before stocking. The optimum stocking density is
turtles, Pelodiscus sinensis. 0.5–1.0 turtle/m2. Broodstock are stocked before the
autumn season so that they can have enough time to
Fish species Body weight Stocking density adapt to their new environment and get enough nutri­
(g) (number/ha) ents for reproduction next summer. They are given spe­
Silver carp cific artificial feed or natural feed, such as fresh trash
Bighead 100–200 500–200 fish, prawn, snails, earthworms and vegetables in the
Crucian carp 100–200 150–450 ponds. Daily management requires strict feeding times
Common carp 300–750 and locations, stable feed quality and suitable quantity,
Grass carp 20–100 300–600 and a quiet environment. Meanwhile, the water depth
Mandarin fish 20–100 100–500 and transparency of broodstock ponds are maintained at
150–300 100–300 150–180 cm and 35–40 cm, respectively. Specific atten­
5–10 tion is paid to the management of water quality and to
disease prevention or control.
sulphate, at a ratio of 5:2 and concentration of 0.7 g/m3.
Medicated feeds may be used, such as those used for fish, All male and female soft‐shelled turtles selected as
if the turtles are in poor health. broodstock must be healthy, without any injury and
more than 3–4 years old. They must be physically robust,
There needs to be quietness when the turtles are bask­ and more than 1 kg and 2 kg body weight for males and
ing on sunny days or they abruptly return to the water females, respectively. The appropriate female to male
and this behaviour, with the advantage of removing foul­ ratio is 3–5: 1. More than 85% of eggs will hatch success­
ing and pathogens from the body surface, is reduced. fully if fertilization of eggs is normal. A high ratio of
females to males reduces the egg fertilization rate, while
21.5 ­Culture Stages a low ratio of females increases fighting amongst the
males, which effects the subsequent survival and recov­
21.5.1 Breeding ery of females after laying.
The cultivation of broodstock turtles is carried out in
specialized outdoor ponds. The pond is disinfected by About 3–5% of the broodstock pond area is established
at the north or west side of the pond for turtle laying at
night during the breeding season, which goes from May

Figure 21.6  A laying site for soft‐shelled turtles. It consists of a Soft‐shelled Turtles 489
raised area of soil along the edge of the pond. There is a covering
roof and ramps for the turtles to crawl up to the laying site. Source: fertilised eggs are put into the sand with animal pole
Reproduced with permission from Qingjun Shao. uppermost (Figure  21.7). Finally, the eggs are covered
with 3–5 cm depth of sand (Figure 21.8). Several layers of
eggs may be kept in a wood container.

The egg boxes are stacked and stored in a hatchery
room (Figure 21.9) Incubation time depends on accumu­
lated temperature, i.e., degree–hours. For example, if the
average temperature during 24 July to 30 July is 28°C, the
accumulated degree hours is 28 × 144 = 4032 degree–
hours. Incubation takes about 36 000 degree–hours. The
best temperature for incubation is 30–32°C, and it takes
about 45 days to complete the incubation period, i.e.,
reach the approximate degree–hours. If sand tempera­
ture is a little higher than 32°C during the incubation
period, the proportion of male turtle hatchlings will be
more than females.

to late August. The laying site consists of about 30–40 cm Figure 21.7  Orderly rows of fertilised turtle eggs on a base of
of fine moist sand under a shed with a cover to protect sand in a hatchery box. Source: Reproduced with permission from
the eggs from sunlight and rain. The laying site environ­ Qingjun Shao.
ment must be stable in water content, sand temperature
and air movement, etc. In order to prevent water flooding
the laying site it is set about 40–60 cm higher than the
pond water level. It is connected by a slope so that turtles
can crawl from the pond to the laying site (Figure 21.6)
and return to the pond after laying their eggs. Some
specific structures are needed near the laying site in
order to prevent rodents, snakes and other wildlife from
eating the turtle eggs.

Twelve to 14 hr after the female has laid, the eggs are
collected and the fertilized eggs selected for hatching.
The animal pole of a fertilized egg must be uppermost;
otherwise the egg will not hatch.

21.5.2 Hatchery Figure 21.8  Covering eggs with more sand. Source: Reproduced
with permission from Qingjun Shao.
There is natural and artificial incubation. Natural hatch­
ing outdoors in pond culture is only 10–40% successful
because of unfavourable weather and predators, while
hatching success under artificial conditions is normally
>90%. During artificial incubation, the interior tempera­
ture is kept between 28–34°C, the relative humidity at
75–85% and the moisture content of the sand bed at
8–12%. Ventilation facilities are needed to supply suffi­
cient oxygen to the eggs. Close attention is paid to orient
the pale or white animal pole of fertilised eggs upper­
most. Two kinds of sands may be chosen for incubation:
river sand and soil sand. Clean river sand with grain size
0.5–1.0 mm is best for egg incubation.

The incubation procedure is to first cover the bottom
of the hatching box with 5–6 cm of sand, and then the

490 Aquaculture

Figure 21.9  Stacking egg boxes before
use in a hatchery room. Source:
Reproduced with permission from
Qingjun Shao.

21.5.3 Nursery water temperature change, the temperature difference
The newly‐emerged hatchling turtles absorb and utilize between indoor and outdoor is kept to less than 3°C.
their remaining yolk, so they do not need any feed during By  the end of October, turtles reach marketable size
the first two or three days. After that, they are fed on (>400 g). The optimum stocking density in earthen
artificial feed or traditional feeds such as zooplanktonic ponds is 2–4 turtles/m2. Turtles are fed twice a day,
copepods and aquatic worms (Limnodrilus hoffeiste) or according to 2%–3% of body weight, at 07:00 and 17:00
liver, fish, shrimp and snails may be used. It takes 3 hr. In the process, it is desirable to keep quiet and not
months for the body weight of hatchling turtles to disturb the turtles from feeding and basking in the sun
increase from 4 to 50 g in the nursery pond. It is the most during the daytime. Basking areas are set near the feed
critical phase because of easy attacks by predators such platform or a feed platform may also be used for basking
as carnivorous fish, birds, frogs and snakes, and fighting in order to reduce the amount of activity. As in cultivat­
each other. A little negligence of management will result ing broodstock turtles, pharmaceuticals are used for
in diseases and high mortality rates. disinfection in water and medicated feeds are adminis­
tered according to the government regulations when
The turtles are fed twice a day, initially at 2% of body turtles are infected.
weight and gradually increasing to about 3%–5% when
using artificial feeds. In practice, the amounts of feed are 21.6 ­Water Quality
based on many factors, such as feed palatability, nutrient
content, water quality, weather conditions, and turtle 21.6.1 Management
health. As they grow, there is size variation within Water management in earthen ponds is as important for
batches. Turtles must be sorted and separated into simi­ soft‐shelled turtles culture as it is for fish culture in
lar‐sized groups in order to prevent them from fighting earthen ponds. It is necessary to keep water transpar­
and harming smaller ones. Because of the high‐density ency to about 25–35 cm in order to avoid turtles biting
and ready morbidity, it is very important to prevent each other and to avoid fungi and parasite diseases. If the
­disease outbreaks, especially from hatchling to juvenile water contains too much plankton, however, there is
stages. need to stock with filter‐feeding fish, such as silver carp
and bighead. Alternatively, 5–25% of the pond surface
21.5.4 Grow‐out area may be stocked with water hyacinth or water cab­
Soft‐shelled turtles are generally reared indoors up to bage or other water plants to absorb nutrients from the
150 g body weight. When outdoor temperature reaches water pond (Wang et al., 2007). Meanwhile, quicklime at
25°C in mid May to early June, turtles are transferred 20–30 g/m3 may be used every two weeks or some of the
from indoors to outdoors. In order to reduce the stress of

pond water exchanged with new water. After harvesting, Soft‐shelled Turtles 491
the pond bottom mud is removed, and the pond bottom Table 21.3  Nutritional requirements of Chinese soft‐shelled
left to dry in the sun for 20–30 days so that bottom turtles, Pelodiscus sinensis.
organic matter can be broken down and be disinfected.
Fertilisers such as pig or poultry manure are used when Nutrient Requirement Source
filling a pond to promote plankton growth or these are
used if the water has poor plankton content during the Protein 33%3, 42%* Wang et al., 2014) (Zhou
turtle farming period. Water transparency of the turtle 43%−50% et al., 2013
pond decreases as the plankton grows. It is undesirable Sun et al., 1997; Qian &
to have trees near earthen ponds, especially on the east Lipid 7%–8% Zhu, 2002
and south sides, in order to maximise the sunlight on the Carbohydrate 18%–25% Qian & Zhu, 2001; 2002
ponds and thus promote plankton and warm water, Sun et al., 1997
* Young juveniles.
21.6.2  Water Parameters
DO, nitrogenous compounds, pH, hardness and other effective feeding practices are essential. Nutrition is the
parameters of waters strongly influence the soft‐shelled most advanced field of soft‐shelled turtle culture and
turtle’s feeding and growth. Generally, DO is maintained their general nutrient requirements have been estab­
at not less than 5–6 mg/L. Although soft‐shelled turtles lished in recent years (Table 21.3). As for other animals in
mainly use their lungs to breathe, they have require­ aquaculture, proteins, lipids, carbohydrates, vitamins,
ments of DO in the water for using pharyngeal villa res­ minerals, calcium and phosphorus, are necessary to meet
piration, especially during hibernation. High DO can the requirements for good growth and health of soft‐
also effectively prevent the anaerobic decomposition of shelled turtles.
organic matter in the water, reducing the levels of NH4+/
NH3, NO2−, H2S, CH4 and other toxic compounds 21.7.1  Nutritional Requirements
(Chapter 4). Intensive farming, with high‐density stock­
ing and artificial feeding, results in considerable organic Protein is the most expensive component in balanced
waste and low DO. So, the process of renewal of DO is fish feeds and often the most important factor affecting
blocked and toxic substances, such as those above, which growth rate of cultured species, and thus there are stud­
cannot be converted into non‐toxic substances, result in ies about the optimal protein requirements of soft‐
‘low‐dissolved oxygen syndrome’, thereby affecting the shelled turtles. Some researchers consider that the
healthy growth of soft‐shelled turtle. Therefore, it is optimal protein levels for this species are at or exceed
essential to maintain the DO of the culture water in the 43g/kg feed (e.g., He et  al., 2002). This was found for
progress of soft‐shelled turtle breeding. post‐hatch juveniles of a Japanese strain of turtles, for
which optimum protein was 42g/kg feed. However, the
It is desirable to rear soft‐shelled turtles in neutral or optimum protein level in feed was ca. 33g/kg feed for
slightly alkaline water, pH from 7.5–8.0, because alkaline small juveniles (ca. 4.8g) (Wang et al., 2014). The specific
water may inhibit the growth of bacteria. The culture water growth rate (SGR) of these latter juveniles increased with
is treated with lime or bleaching powder (chlorine) every protein content up to this level and did not increase at
15 days at a dose of about 2–3g/m3 in order to regulate the higher levels. Protein efficiency ratio (PER) increased
pH and kill pathogenic microorganisms and parasites. with feed protein content up to 33g/kg and then declined
at levels above this.
Ammonia nitrogen (NH3‐N) is the main toxic substance
in the water that causes turtles to be poisoned if excessively Basically, the protein requirements of Chinese soft‐
accumulated. Therefore, the content of ammonia nitrogen shelled turtle reflect their requirements of essential and
in water is tested regularly to keep it less than 0.02 mg/L. non‐essential amino acids. These amino acid require­
Other water parameters such as hardness and NO2− must ments have been estimated through studying the amino
also be regulated by water controlling methods. acid content of muscle and ‘skirt’ (leathery edging of the
carapace) tissue (He et al., 2002).
21.7 ­Nutrition, Feeding and Feed
Formulation There is no systematic report on requirements for
lipids such as EPA and DHA for soft‐shelled turtles.
Feed costs are the largest component in the production of
Chinese soft‐shelled turtles, accounting for 35–45% of Feed supplements have been tested and found to influ­
the total cost. Efficient and economic feeds, together with ence the growth and health of soft‐shelled turtles:

●● Vitamin C. There is a dietary requirement for ascorbic
acid (vitamin C) (Vc) to obtain maximum growth of
soft‐shelled turtles when cultured indoors in dark con­
ditions, although soft‐shelled turtle can synthesize a
small amount (Shao et  al., 2004). Ascorbic acid is

492 Aquaculture Table 21.4  Typical commercial feed formulation for Chinese
soft‐shelled turtles, Pelodiscus sinensis.
­provided in feeds in the form of phosphorylated L‐
ascorbic acid at 184–192 mg/kg feed. % ingredient
●● Vitamin C. A level of 370–380 mg/kg feed gave optimal
carapace collagen and strength (Wang & Huang, 2015). Ingredients Hatchling Turtles Turtles
●● Vitamin E. A level of 250–500 mg/kg feed significantly up to 50 g 50 to 150 g >150 g
improved non‐specific immune response, i.e., blood White fishmeal body wt body wt body wt
cell phagocytosis and serum bactericidal activity Brown fishmeal
(Zhou et al., 2005). α‐starch 60 52 48
●● Iron. A level of ca. 280 mg/kg iron in feed, as ferric Wheat flour –3 6
citrate, significantly improved growth rate, food con­ Soybean meal
version ratio (FCR) and protein efficiency ratio (PER) Fermented bean 22 22 20
in juvenile turtles (Chu et al., 2007). meal –– 2
Animal liver meal –2 3
21.7.2  Feed Formulation and Manufacture Corn protein meal 5
There were three stages in the development of feeds for Wheat gluten 23
soft‐shelled turtles: Yeast meal 2
●● The first was from the 1970s to the early 1990s. There Ca(H2PO4)2 5 3 3
Mineral premix – 2 1
was extensive culture and the main features of the Vitamin premix 3 3
feeding regime were directly feeding many ingredients Zeolite powder 3 3 1.5
including high levels of waste products, resulting in 1 1.5 2
poor food conversion ratios (FCR). Total 1.5 2 2
●● The second stage from the early 1990s to the mid‐ 2 2 1.5
1990s was the formulated feed stage. It was character­ 2 1.5 100
ized by using compound feeds, such as commercial eel 1.5 100
feed, and gradually optimizing ingredients for soft‐ 100
shelled turtles.
●● The third stage of the industry is a relatively low‐pro­ semi‐moist feed pellets. The feed must be sufficiently
tein, high‐quality stage, which is characterised by feed viscous so that it is not easily spread by the turtle crawl­
with reduced crude protein content and feed costs cor­ ing around during its long period of feeding, which is
respondingly lowered. about 30 minutes to 2 hours according to its body size.
Feeds used in intensive pond culture of soft‐shelled Fine particles are required so that the feed can be
­turtles are formulated to provide almost all required digested and absorbed easily by the turtles.
nutrients in the proper proportions. Typical commercial
feed formulations are shown in Table 21.4. The feed pro­ 21.7.3 Feeding
tein is mainly provided by expensive imported white During the nursery stage, the turtles are fed 3–5 times
fishmeal. The crude protein content of white fishmeal is per day. This begins in the early morning (6 am) and ends
about 65%, while that of brown fishmeal (from oily fish) at night (10 pm), especially in indoor culture. At body
is about 55%. If a proportion of white fishmeal could be weight more than 150 g it is sufficient to feed the turtles
replaced by a plant source of protein or microbe protein, twice a day, i.e., in the morning (7 am) and in the after­
the feed costs could be decreased to the advantage of the noon (5 pm), as is practiced in feeding some fish. Feeding
industry. The commonly‐used ingredients in commer­ must be under water during the nursery stage to encour­
cial compound feeds are mainly white fishmeal, brown age the juvenile turtles to feed and grow well. At body
fishmeal, soybean meal, fermented bean meal, wheat weight more than 100 g, the feed is placed on a slope
gluten, corn protein meal, yeast, animal liver meal, α‐ above water level where the turtles emerge to feed. This
starch, wheat flour, corn or soybean oil, Ca(H2PO4)2, reduces feed waste and, in ponds, avoids the possibility
vitamins, and minerals. of wild fish taking the expensive turtle feeds.
All the solid ingredients need to be ground into fine
particles smaller than 200 μm, and then mixed well. The food intake per day of the turtles during the suitable
Then every 100 kg of compound powdered feed needs culture season is about 2–3% of body weight with artificial
the addition of about 2–4 kg plant oil or some fish oil to particle feeds or 5–10% of body weight with fresh feeds.
supply sufficient fatty acid requirements and energy. However, in ponds, the feeding rate needs to be adjusted
About 20% water is added and a machine is used to make according to weather condition, water temperature, water

quality, turtle health, and other factors. In farming Soft‐shelled Turtles 493
p­ ractice, this means that the feed needs to be enough for a
feeding period of about 2 hours for nursery turtles and at There have been a number of studies on the preven­
least an hour for turtles with body weight of more than tion and control of parotitis, including Chen (1994) and
150 g. Otherwise, there is insufficient feed. Alternatively, Xu (2002).
it is necessary to avoid overfeeding with feed loss and
wastage, and potential loss of water quality. 21.8.2  Bacterial Diseases

Cleaning and using quicklime are very necessary to 21.8.2.1  White Plastron Disease (Haemorrhagic
disinfect the feeding site after the turtles have finished Intestinal Necrosis)
feeding in order to reduce or prevent disease breakouts Pathogens: Aeromonas hydrophila, Edwardsiella tarda,
Proteus vulgaris
21.8  Infectious Diseases2 Symptoms: The bodies of sick turtles are pale, showing a
state of extreme anaemia and oedematous. The liver is
Soft‐shelled turtles grow slowly and are seldom mori­ grey and brown with little or no blood; the gallbladder is
bund in their natural environment. However, with the swollen; the kidneys and spleen are dark. The body mus­
development of intensive culture and modified environ­ culature is pale and bloodless. Juvenile turtles (100–200
mental conditions in culture, there has been a significant g) are susceptible, particularly from May to July when the
increase in diseases of soft‐shelled turtles. According to water temperature is 25–30°C (Chen, 1994).
incomplete statistics, the overall disease incidence in
farmed soft‐shelled turtles is 20–40%. The mortality rate 21.8.2.2  Putrid Skin Disease
may be 20–50% in some poorly‐managed farms. There Pathogens: Aeromonas hydrophila, Aeromonas sobria,
are some common diseases, such as parotitis, white plas­ Pseudomonas Species and other Bacteria
tron (ventral portion of carapace) disease, haemorrhage, Symptoms: Surface erosion and ulceration are the main
perforation disease, enlarged and red neck disease, skin symptoms of this disease. Lesions can also occur on
ulcer disease, and fungus disease (dermatomycosis). One limbs, neck, carapace, skirts and tail. Initially, part of the
disease often results in many symptoms, and one symp­ skin is inflamed. Then there is necrosis followed by
tom results from several diseases, so that it may be very ulceration of the affected area, which gradually increases
difficult to diagnose and treat turtle diseases. until muscles and bone are exposed. In severe cases, the
neck bones are exposed, limbs rot away and claws fall off.
Controlling water quality is the most important way to This disease frequently occurs in high‐density indoor
avoid disease outbreaks. culture.

21.8.1 Viruses 21.8.2.3  Furunculosis Disease
21.8.1.1  Parotitis (‘Mumps’) Pathogen: Aeromonas hydrophila punctata
Symptoms Symptoms: In the early stage, small white bulges appear
Parotitis is evident in sick turtles that are generally on the surface of the turtle’s skin. They gradually become
drowsy and with a floppy neck so that the turtle’s head more prominent, expanding and forming boils. In severe
cannot draw back into its shell. Their parotid (salivary) cases these become festering holes in the carapace con­
glands, mouth, oesophagus, and intestines are abnormal. current with the skin disease. This disease infects both
The liver is grey to brown colour and fragile. Infected juvenile and adult turtles, and is most common from
turtles in the same pond will sometimes present two May to July, when the temperature is at 20–30°C.
kinds of disease symptoms:
●● Parotid glands congested with blood and reddish; 21.8.2.4  Perforation Disease
Pathogens: Aeromonas hydrophila, Proteus vulgaris,
eroded, with secretions; mouth, oesophagus and intes­ Klebsiella pneumoniae, Alcaligenes Species
tines inflamed; plastron, limbs and tail are swollen Symptoms: In the early stage, white sores of 2 to 10 mm
with blood. diameter appear on the soft‐shelled turtle’s dorsal shell,
●● Parotid glands whitish and eroded, with secretions; plastron and skirt. The sores develop scabs and bleed.
oesophagus, stomach and intestine congested with The scabs soon fall off, with the original sore site left as a
necrotic tissue; plastron white without any blood colour. small hole with inflamed edge. There is bleeding from
the interior of the hole in severe cases. This disease
2  See also http://www.fao.org/fishery/culturedspecies/Trionyx_ can  infect all stages of soft‐shelled turtles but occurs
sinensis/en (accessed Novemeber 2016) ­especially in juvenile turtles and especially during indoor
culture.

494 Aquaculture sediment. When treading on a turtle, they capture the
turtle using their hands.
21.8.3  Fungal Diseases ●● Rake capture. Rakes made of wood cause less damage
21.8.3.1  White Speckle Disease to the soft‐shelled turtles than metal ones. The rake
Pathogen: Mucor Species handle length is about 1.5 m; the space between teeth
Symptoms and damage: White spots appear on the cara­ is 10–20 cm. Rake teeth are inserted deep into mud.
pace of soft‐shelled turtles in the early stages and are not The soft‐shelled turtles are detected by contact with
easily detected. Then the white spots gradually increase the rake’s teeth and then captured by hand. This
and extend to other parts of the body, forming a white‐ method is used to capture adult turtles, broodstock
spotted necrotic epidermis, which peels. This disease is turtles and turtles after hibernation.
common from April to June and mainly affects juvenile ●● Purse seine capture. The meshes of the purse seines
turtles in the nursery phase (Chen, 1994). are slightly larger than the meshes of fish nets. The
seine net is set and taken in smoothly and rapidly
21.8.4  Protozoan Parasites because turtles will go into the sediment if there is
There are several kinds of endoparasitic protozoa, such some sound.
as Trypanosoma species, and species of Myxosporidia Drained‐pond capture. If large numbers or a whole
and Coccidia; while Vorticella is an ectoparasite. pond of turtles are to be captured, the pond is drained
and dried, and the turtles collected from around the pool
21.8.4.1  Vorticella Disease during the day and by using lights at night
Pathogen: Vorticella Species
Symptoms and damage: This stalked ciliate infests the 21.9.2  Processing and Cooking
surface of turtles at very high densities. The limbs, cara­ There are hundreds of processing and cooking methods
pace, plastron, skirts and neck of the sick turtles have in Chinese cuisine.
white lesions. When the water is deep green, the vacu­
oles of the ciliate are densely green and the whole sur­ The soft‐shelled turtle is killed by cutting the neck or
faces of the soft‐shelled turtles are green. The disease opening the ventral shell. The turtle is cleaned by remov­
does not lead to the death of soft‐shelled turtles, but ing the viscera, and it is then ready for processing and
their feeding and growth rate decrease. cooking. The main processing and uses of soft‐shelled
turtle include:
21.8.5  Metazoan Parasites ●● cooking to produce a great variety of dishes;
Leeches ●● health food medicines;
Leeches are common ectoparasites of soft‐shelled turtles. ●● health food medicines through processing with tradi­
They infest the turtles’ body surface, skirts and limbs,
causing irritation, loss of appetite and body weight. This tional Chinese medicines; and
leads to malnutrition and, if serious, can cause death. ●● mixing with other traditional Chinese medicines as a

21.9 ­Harvesting and Processing kind of medicine for treating some specific human
diseases.
After soft‐shelled turtles reach the desired market size,
they are harvested, transported to the processing plant 21.9.2.1  Cooked as Dishes
and processed. These practices are relatively standard­ There are many ways of cooking soft‐shelled turtles,
ised across the industry. including boiling, frying, steaming, soaking (e.g., in rice
wine) or making into soup, for a great variety of dishes.
21.9.1 Harvesting These may involve the whole or parts of the turtle cooked
Soft‐shelled turtles may be harvested year around, with other edible animal tissues, vegetables or edible
according to consumer demand. However, they tend not plant seeds. Cooked soft‐shelled turtles may be vacuum
to be harvested during the rapid growth period from July packed for sale.
to September. There are many methods for harvesting:
●● Hand capture or rake capture are effective when small 21.9.2.2 Medicines
Healthy Food Medicines
numbers are requested. Collectors wearing protective The soft‐shelled turtle is cooked with traditional Chinese
pants, going downstream and using their feet in the medicines, plant seeds or tissues as medicinal food for
sick or weak persons. It is a food to support body health
and food for health recovery.

Soaking in Alcohol with Traditional Chinese Medicines Soft‐shelled Turtles 495
Slaughtered and cleaned soft‐shelled turtles or their organs
are soaked in rice wine with traditional Chinese medicines years of culture, for a high price. Small quantities of
for daily drinking to support the human body’s health. soft‐shelled turtle are processed and packed, then sold
in local markets or supermarkets, or exported to Japan,
An Ingredient of Medicines South Korea and other Southeast Asian countries. The
Whole or parts of the soft‐shelled turtle are used as an turtles with brand names are sold at 3–5 times and
ingredient of traditional Chinese medicines by powder­ even 10 times the price of turtles without brand names,
ing and specified processing. In addition, the turtle’s even in China. These brand‐name turtles are of high
shell is traditionally used as a medicine for children and quality with a culture period of 3–5 yr in earthen
old people as a calcium supplement. ponds or polycultured with fishes or aquatic plants.
The turtle’s price at a city supermarket or at a brand‐
21.9.3 Marketing name shop may be 300–400 CNY/kg or even higher, if
Usually, soft‐shelled turtles are harvested and sold alive it is polycultured with fish for 4–5 yr.
after they weigh 400 g. The main marketing methods are: Despite these high prices, the farm gate price of indoor
●● the turtles are sold alive by the farmer at the pond side cultured soft‐shelled turtles was only about 30–32 CNY/
kg in Hangzhou in July 2009, since consumers consid­
or farm gate to middle‐men or restaurants. The mid­ ered that the quality of these soft‐shelled turtles was
dle‐men whole‐sale the turtles to local market dealers, much poorer than those cultured in earthen ponds. The
who finally sell to the consumers. price of soft‐shelled turtles depends on many factors that
●● the farmer takes the turtles to the local market which affect turtle quality: period of culture, culture environ­
sells vegetable, meat and aquatic products, and there ment (e.g., pond or dark indoors), geographic origin,
sells directly to the consumers (Figure 21.10). body weight, sex (males are more valuable), condition of
●● a soft‐shelled turtle production company sells them health, and status of brand name.
through the company’s specialised shops in cities, with In retail markets, dealers may help customers by
a marked brand and quality guarantee or specified slaughtering and cleaning the soft‐shelled turtle after
weighing if the customer requests this.

21.9.4 Consumption
Most Chinese, Japanese, Korean and Southeast Asian peo­
ple like to eat soft‐shelled turtles. They are often chosen as
one of the dishes for special occasions such as traditional
holidays, festivals, banquets, family gatherings, friends get­
ting together, birthday parties, business meetings and wed­
dings. This is because soft‐shelled turtles are tasty and
considered to have high nutritional value for health. During
the meal every participant will usually take one or two
pieces of turtle meat with their chopsticks and they will also
have some turtle soup. An example of a special dish of
cooked Chinese soft‐shelled turtle is shown in Figure 21.11.

Figure 21.10  Soft‐shelled turtles, Pelodiscus sinensis, and toads for 21.10 ­The Future of Soft‐Shelled
sale in a market, Xiamen City, Fujian Province, China. Source: Turtle Farming
Reproduced with permission from Qi Lin.
Based on Chinese traditional food culture, many people
would like to consume soft‐shelled turtle if the quality is
good and safe. There will be increasing consumption with
increasing economic development in most parts of China.
More soft‐shelled turtles will be produced through fish‐
turtle polyculture or ecological culture methods in earthen
ponds and in greenhouses with sunlight, since there are
fewer disease breakouts with these methods compared to
indoor dark culture. There are needs to improve survival

496 Aquaculture ­produce many culinary dishes and used in a variety
of medicines
Figure 21.11  A Chinese dish of soft‐shelled turtle soup. Source:
E. Andrade 2006. Reproduced under the Creative Commons ●● Soft‐shelled turtles are voracious feeders and omnivo­
Attribution NoDerivatives license, CC‐BY‐ND 2.0. rous. They are amphibious with lungs for aerial respi­
ration and a pharyngeal organ with villi‐like gills for
rate during the nursery phase, reduce the period of the aquatic respiration. As reptiles, their body tempera­
nursery phase and improve turtle meat quality. This is ture, and hence metabolic rate and behaviour, vary
likely to be solved by two‐stage farming methods with an with their immediate environment to the extent that
indoor temperature‐controlled nursery phase and then behaviour ceases below 10°C. This results in slow
culture in outdoor ponds or in sunlit greenhouses. There growth and a longer period to sexual maturity in farms
are geographic strains of P. sinensis (e.g., Zhou et al., 2013) at high latitudes.
and there may be substantial genetic variation in a popula­
tion (Que et al., 2007). New strains and hybrid strains will ●● Reproduction follows a typical reptilian pattern. The
be bred extensively for production on a larger scale. male fertilises the female through copulation. Eggs are
Chemical treatments that are more effective and leave fertilised internally and then laid to hatch later. Eggs
fewer residues must be developed for disease control dur­ for culture are collected and placed in hatching boxes
ing culture. Finally, it is most important to train the farmers in sand. Incubation time then depends on degree–
in basic culture knowledge such as how to: hours, i.e., 28° × 144 hr = 4032 degree–hours.
●● control water quality;
●● choose appropriate methods for disease prevention ●● Farming methods consist mainly of indoor concrete
tanks, outdoor earthen ponds or a combination of both
and control; where juveniles are reared indoors and transferred.
●● set up turtle farmers’ associations; and The quality of turtles cultured indoors is lower than
●● improve the management of farming risks and other those from earthen ponds and antibiotics are used
more frequently. However, indoor culture has the eco­
aspects of soft‐shelled turtle production. nomic attractions of a shorter period to marketable
size and lower costs. Pond culture is often polyculture
21.11 ­Summary with deliberate stocking of fish and aquatic plant
s­ pecies to improve the quality of turtles. These turtles
●● Chinese soft‐shelled turtles, Pelodiscus sinensis, are comparable in quality to wild turtles and thus
do not have the usual hard and fused shell plates of valuable.
most turtles. They are cooked with the shell to
●● Farmed soft‐shelled turtles require high protein
feeds and feeds are the largest cost in producing
the  turtles. The feeds account for 35–45% of the
total cost. Considering this, there has been sub­
stantial research on turtle nutrition and their gen­
eral requirements have been established in recent
years.

●● Soft‐shelled turtles are seldom moribund in their nat­
ural environment. However, there is often significant
disease in culture. Skin diseases are common and con­
trolling water quality is particularly important for
avoiding disease outbreaks.

●● There will be increasing demand for soft‐shelled
t­urtles, dependent on quality. Consequently, it
is  important to set up farmers’ associations and
training.

References turtles, Pelodiscus sinensis. Aquaculture, 269(1–4),
532–537.
Chen, P. F. (1994). Prevention trial of complication diseases He, R. G., Mao, X. Y., Wang, Y. L. et al. (2002). Study on the
of soft‐shelled turtles, ‘White Spot’, ‘piercing’, ‘mumps’. optimal levels of energy, crude protein and essential
Freshwater Fisheries (Chinese), 24: 38–39. amino acid model of diets for growing turtle. Journal of
Fisheries of China (Chinese), 24, 46–51.
Chu, J‐H., Chen, S‐M. and Huang, C‐H. (2007). Effect of
dietary iron concentrations on growth, hematological
parameters, and lipid peroxidation of soft‐shelled

Ling, S. W. (1977). Aquaculture in Southeast Asia: A Historical Soft‐shelled Turtles 497
Review. University of Washington Press, Seattle.
Wang, C‐C. and Huang, C‐H. (2015). Effects of dietary
Qian, G. Y. and Zhu, Q. H. (2001). The impact of different vitamin C on growth, lipid oxidation, and carapace
growth conditions on nutrients content of the Chinese strength of soft‐shelled turtle, Pelodiscus sinensis.
soft‐shelled turtles. Journal of Nutrition (Chinese), 23, Aquaculture, 445,1– 4.
181–183.
Wang, J., Qi, Z. and Yang, Z. (2014). Evaluation of the
Qian, G. Y. and Zhu, Q. H. (2002). The impact of feed types protein requirement of juvenile Chinese soft‐shelled
on nutrients content of soft‐shelled turtles. Journal of turtle (Pelodiscus sinensis, Wiegmann) fed with practical
Fisheries (Chinese), 26, 133–138. diets. Aquaculture, 433, 252–255.

Que, Y., Zhu, B., Rosenthal, H. et al. (2007). Isolation and Wang, M., Ma, J. J. and Shao, Q. J. (2007). The earth pond
characterization of microsatellites in Chinese soft‐ culture of soft‐shelled turtle Trionyx sinensis. Reservior
shelled turtle, Pelodiscus sinensis. Molecular Ecology Fisheries (Chinese), 27, 24–26.
Resources, 7(6), 1265 – 1267.
Xu, J. H. (2002). Effective control of turtles parotitis. China
Shao, Q. J., Zhang, L. H., Liu, J. X. et al. (2004). Effect of Fisheries, (9): 50–52.
dietary Vc supplementation on growth and tisssue Vc
content in juvenile soft‐shelled turtle Trionyx sinensis. Zhou, F., Ding, X., Feng, H. et al. (2013). The dietary
Acta Hydrobiologica Sinica, 28(3), 269–274. protein requirement of a new Japanese strain of juvenile
Chinese soft shell turtle, Pelodiscus sinensis.
Sun, H. T., Xuan, Z. Q., Wang, Z. Z. et al. (1997). The Aquaculture, 74, 412–413.
requirement of fat‐sugar mixtured salts and amino acid
of soft‐shelled turtles. Chinese Fisheries Society Aquatic Zhou, X., Niu, C. and Sun, R. (2005). The effects of vitamin
Animal Nutrition and Feed Research Papers, 1, 241–249. E on non‐specific immune response of the juvenile soft‐
shelled turtle Pelodiscus sinensi. Fisheries Science, 71(3),
612–617.



499

22

Shrimps

Darryl Jory

CHAPTER MENU 22.8 Production Management and Harvest,  513
22.1 Introduction, 499 22.9 Nutrition, Formulated Diets and Feed Management,  518
22.2 Cultured Species,  502 22.10 Emerging Production Technologies and Issues,  521
22.3 Grow‐Out Systems,  503 22.11 Responsible Shrimp Farming and the Challenge of
22.4 Preparation of Ponds,  506
22.5 Reproduction and Maturation,  508 Sustainability, 524
22.6 Hatchery Design and Larval Culture,  510 22.12 Summary, 524
22.7 Seedstock Quality and Stocking,  512
References, 525

22.1 ­Introduction University, succeeded in spawning the Kuruma shrimp2
(Marsupenaeus japonicus). He cultured larvae through
22.1.1  History of Shrimp1 Farming to market size in the laboratory and successfully mass
In the last three decades, farming of various shrimp produced them commercially. Dr Fujinaga generously
species has developed tremendously. In 2015, shrimp shared his findings and published papers on his work
farms contributed ca. 60% of the world’s shrimp demand, during the next 40 years. He was honoured by Emperor
continuing to replace traditional fisheries as market Hirohito with the title ‘Father of Inland Japonicus
demand suppliers. In addition to generating 25 billion Farming’. In the early 1970s, researchers and entrepre­
USD in trade, shrimp farming also provides employment neurs in various countries in Asia and Latin America
for millions of people in developing nations, by: became involved in promoting development of the
●● incorporating into production vast areas of previously industry, which grew steadily. Shrimp farming has come
a long way in the last 25 years, and enormous progress
unutilised coastal land unsuitable for other types of has been made in developing technologies and methods
development; to culture shrimps. The industry began a tremendous
●● producing a valuable commodity that is increasingly expansion in the early 1980s. Major references on global
marketed locally in many countries; and shrimp farming include Browdy and Jory (2001, 2009),
●● generating needed jobs and hard currency through and Alday‐Sanz (2010).
significant exports.
The industry has also generated some environmental 22.1.2  Current Status and Production
issues that have been acknowledged and properly Shrimp farming has been practised worldwide in over 60
addressed in most cases. countries for at least the past four decades, but produc­
Shrimps have been grown in South‐East Asia for tion is mostly concentrated in about 15 nations in Asia
centuries by farmers who raised them as incidental crops and Latin America (Figure 22.1). These regions account
in tidal fish ponds. Modern shrimp farming began in the for about 95% of all farmed shrimps. Since 1992, about a
1930s, when Motosaku Fujinaga, a graduate of Tokyo dozen countries have contributed about 95% of farmed
shrimp production and the top world producers have
1  ‘Shrimp’ is used for species of the family Penaeidae. ‘Shrimp’ is most been, at various times, Ecuador, Taiwan, Indonesia,
widely used for these species, but in some countries they are known
as ‘prawns’. It doesn’t include species of the family Palaemonidae 2  Known as the Kuruma prawn in FAO data
which are also known as shrimp.

Aquaculture: Farming Aquatic Animals and Plants, Third Edition. Edited by John S. Lucas, Paul C. Southgate and Craig S. Tucker.
© 2019 John Wiley & Sons Ltd. Published 2019 by John Wiley & Sons Ltd.

500 Aquaculture

Production (mmt)(a) Other
5.0
Middle East
4.5 –6% /Northern
4.0 Africa
Americas
3.5
3.0 India
2.5
China
2.0
1.5

1.0

0.5
0.0

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Production (mmt) (b)
1.8
1.6 China Thailand Vietnam Indonesia India
1.4
1.2 2011 2012 2013 2014 2015 2016 2017 2018
1.0
Production (Thousand mt) 0.8
0.6
0.4
0.2
0.0

(c)
400
360
320
280
240
200
160
120
80
40
0

Ecuador Mexico Brazil Honduras Nicaragua Venezuela

2011 2012 2013 2014 2015 2016 2017 2018

Figure 22.1  Total shrimp farming production (a) and production by the two major global regions: Southeast Asia (b) and the Americas
(c). Sources: FAO (2008−2011); FAO and GOAL3 2014 (2012−2013); FAO and GOAL 2015 (2014); GOAL 2016 (2015−2018). From Anderson
et al. (2016). mmt = million t (or 1 x 106 t); thousand mt = thousand t (or 103 t). Source: Reproduced with permission from Darryl Jory.

China and Thailand. The shrimp farming industry in almost 5 million t: the latest global production estimates
China has really exploded in recent years, and the for 2014 (FAO) totals 4.875 million t.
country has uninterruptedly been the world’s leading
producer since at least 2003 (Figure 22.2). Production is still increasing in various countries by
responsibly intensifying culture methods, without having
Global production has been increasing steadily in the to develop large areas. Most of the best locations for farms
past two decades, from about one million t in 1995 to have already been developed, but the industry can still
expand in several countries, including various Latin
3  Global Aquaculture Alliance. American and African nations. There are shrimp farms in

Shrimps 501

2000Production (103 t/yr) aquafeeds, and as the industry moves to comply with
new international standards on product quality and the
1500 environment. Globally, industry growth in the past dec­
ade or so has fluctuated between ± 6%/yr and is currently
1000 expanding at around 4%.

500 Through 2011, farmed shrimp production increased
steadily in east Asia and averaged a 6% annual growth rate
0 from 2008 to 2011. The GOAL (Global Outlook for
2000 2002 2004 2006 2008 2010 2012 2014 Aquaculture Leadership) surveys indicate that production
Figure 22.2  Recent growth of shrimp farming in China (FAO, 2016). decreased from 3.45 million t to 3.25 million t in 2012 (down
Source: Reproduced with permission from John Lucas. 5.8%) and 3.21 million t in 2013 (down 1.1%) due to the
impact of the Early Mortality Syndrome (EMS; also known
Algeria, Egypt, Nigeria, Ghana, Mozambique, Madagascar as Acute Hepatopancreatic Necrosis Syndrome, AHPND)
and probably several more African countries. Shrimp cul­ in China, Vietnam, Thailand and Malaysia. In 2014, produc­
ture is a very minor activity in several European countries tion increased significantly to 3.49 million t (up 8.5%) in
(Spain, Italy, France, Netherlands, Latvia and others), and large part due to larger harvests reported in China, India and
Japan and the USA are relatively small producers owing to Vietnam. Figure 22.1 shows production in Southeast Asia,
cool weather, high production costs, limited areas with China and the Americas, by the major Latin American pro­
suitable conditions, and the difficulty of competing cost‐ ducing nations, which include Ecuador, Mexico, and Brazil.
efficiently with industry leaders. In the USA, at least 100
or more small producers, mostly using indoor recirculat­ In Asia and the Americas the industry is expected to
ing systems, are growing shrimps for local niche markets. continue its consolidation into very large, vertically‐inte­
grated companies that can maximise economies of scale
Many developed countries are indirectly but neverthe­ and efficiency. And it is expected to expand significantly
less significantly involved in the shrimp farming industry in the next two decades, particularly in India, Southeast
as large consumers, as producers of supplies and materials Asia and Latin America, with current production expected
for the industry, and in providing substantial technical to nearly double by 2030.
expertise on production and processing techniques.
Currently, close to 75% of farmed shrimp production in
The industry generates at least 4 million direct jobs the world is Pacific white shrimp, and this percentage will
and many more indirectly through ancillary industries. continue to increase (Figure 22.3). Improvements in selective
It also generates USD 12−15 billion in international trade breeding, nutrition, health management, disease diagnosis
annually, ca. 10−15% of all seafood of all origins traded and prevention, and more efficient and intensive production
globally. It also creates much more additional economic systems have supported this industry expansion.
activity centred on ancillary industries like aquafeeds,
processing, various equipment, pharmaceutical chemicals, Asian farmers have demonstrated that Specific Pathogen
transportation, marketing, R&D and others. It is based Free (SPF) L. vannamei, often from selective breeding
mostly on one species with relatively few selectively‐bred, programs, can be efficiently grown at very high densities
improved lines. The Pacific white or whiteleg shrimp with relatively low environmental impacts. However,
(Litopenaeus vannamei) is the most important species in while there are farms in the Americas that have been able
the world, with virtually all production coming from
aquaculture. This species represents around 75% of all Production (103 t/yr) 5000 All shrimp
farmed shrimps globally, and over 40% of all shrimps 4000 Whiteleg shrimp
produced in the world (FAO, 2016).
3000
Between 1975 and 1985, global production of farmed
shrimps increased by 300%, and between 1985 and 1995 2000
by 250%. Since 1995, however, industry growth has been
significantly slower due to various viral and bacterial 1000
diseases (Figure 22.1a). Costs have continued to increase
and market prices have experienced substantial fluctu­ 0 1995 2000 2005 2010
ations over the past decade or so, with major variability 1990
and unpredictability in the costs of most inputs like energy
and grains, with significant ingredient replacement in Figure 22.3  Recent output from farming Pacific white shrimp or
whitteleg shrimp (Litopenaeus vannamei) versus output from
farming the black tiger shrimp, Penaeus monodon. Source:
Reproduced with permission from John Lucas.

502 Aquaculture Black tiger shrimp alone probably constituted 60–70% of
the world’s production of farmed shrimps until the end of
to successfully convert from semi‐intensive to more the century, when the Pacific white shrimp began to be
intensive production modes, these are relatively rare. introduced to Asia, where it has essentially replaced black
There does not appear to be any real move towards the tigers in production and world markets. Both species are
widespread adoption of this technology in the region, as popular in local and export markets, and although both
land availability has not been a constraint to industry are relatively easy to produce, L. vannamei has some very
establishment and growth. Production models in the definite advantages regarding domestication, larval rear­
Americas remain largely based on: ing, tolerance to high density culture and requirements
●● large ponds (5−10 ha) stocked at 10−30 animals/m2; for lower protein aquafeeds. The seedstock (PL) for both
●● using hatchery‐reared postlarvae (PLs) often selected species can be produced in hatcheries using relatively
simple technologies. Both can tolerate a wide range of
for growth and survival against prevailing pathogens; salinity, from slightly greater than freshwater (1–2‰) to
●● with some mechanical aeration; full‐strength ocean water (35–40‰; L. vannamei will
●● reduced water exchange rates; and grow well at up to 55‰). Both species readily eat formu­
●● continued use of manufactured aquafeeds. lated commercially manufactured feeds.

22.2 ­Cultured Species 22.2.1  Western White Shrimp54
(Litopenaeus Vannamei)
There are about 2500 species of shrimps worldwide, but This species is known as the Pacific white or whiteleg
only seven species are farmed to some degree. All belong shrimp (Figure  22.4). Its original range was from the
to the family Penaeidae, characterised by a rostrum with Gulf of California southward to northern Peru, but it is
ventral and dorsal teeth, and last thoracic segment with now a cosmopolitan species. Males reach a total length
gills. Out of the commercially farmed species, two of 187 mm and females 230 mm. It is well suited for
account for around 95% of global production: farming, because it:
●● the black tiger shrimp43(  Penaeus monodon) in Asia; and ●● breeds well in captivity;
●● the Pacific white shrimp (Litopenaeus vannamei), ●● can be stocked at small sizes;

native of the western coast of the Americas, but widely
and often indiscriminately introduced throughout
Asia, Africa, Europe and elsewhere.

Figure 22.4  The Pacific white shrimp or
whitteleg shrimp (Litopenaeus vannamei).
Source: Reproduced with permission from
Darryl Jory.

4  Known as the ‘giant tiger prawn’ in FAO literature. 5  Known in FAO statistics as the ‘Whiteleg shrimp’.

Shrimps 503

●● grows fast and at uniform rates; 22.3 ­Grow‐Out Systems
●● has comparatively low protein requirements (20–25%)
Shrimp grow‐out operations span a wide continuum in
and, together with the Indian white shrimp, Fennero­ terms of intensity, complexity and technology. Globally,
penaeus indicus, is considered among the most four grow‐out production systems are generally recog­
omnivorous of the cultured penaeid species; and nised, which share some characteristics, but differ in
●● adapts well to variable environmental conditions. other aspects (Table 22.1).
Litopenaeus vannamei has advantages over P. monodon
in that it breeds in captivity more readily. Overall sur­ Moving from the lowest towards the highest stocking
vival in hatcheries is relatively high at 40–60%. systems, there is:
Many hatcheries in Latin America have captive stocks
of L. vannamei broodstock, some pathogen free, some ●● progressive reduction in the area of ponds used, even­
pathogen resistant, with some having been in captivity tually moving towards more intensive systems like
for 40 years. Established selective breeding programs in tanks and raceways, and even indoors for more con­
both Asia and the Americas have made significant trolled conditions and biosecurity;
advances in the genetic improvement of important traits
like growth and disease resistance. ●● progressive increase in capital, production costs and
22.2.2  Black Tiger Shrimp stocking densities, and risk;
(Penaeus Monodon)
Penaeus monodon is the largest (363 mm maximum ●● a trend for increased use of intermediate nursery or
length) and fastest growing (up to 5.5 g/week) of the multiple phases; and
farmed shrimps (Figure 22.5). The species is native to the
Indian Ocean and the south‐western Pacific Ocean, from ●● an overall intensification in production practices,
Japan to Australia, and dominates production every­ management and technology.
where in Asia except for Japan and China. This species
can tolerate a wide range of salinities and is grown in The last involves a more thorough preparation of
inland low‐salinity ponds in some countries. It is, how­ ponds or tanks, the lining of ponds with high density
ever, very susceptible to several shrimp pathogens, polyethylene liners (HDPE, which allow faster restocking
although it appears to be less affected by Early Mortality and the use of higher levels of mechanical aeration),
Syndrome EMS = AHPND than L. vannamei. Breeding total use of laboratory‐produced seed‐stock, use of
in captivity is relatively more difficult to induce and better formulated and more nutrient‐dense feeds,
hatchery survival is lower (30−40%). improved pond management practices and others.
Up to the mid‐ to late‐1990s, it also involved higher
Figure 22.5  The black tiger shrimp (Penaeus monodon). Source: rates of water exchange, but for the last two decades
Reproduced with permission from Darryl Jory. there has been a strong global trend towards reduc­
ing exchange rates and the volume of water required
to produce shrimps (i.e., m3 water/kg shrimps)
(Figure 22.6). This has even developed to the point of
reaching zero exchange (except for replacement of
water lost to evaporation and other processes) and
recirculation to improve biosecurity and operational
cost‐efficiency. There are also trends towards increased
use of technology, aeration, technical and professional
labour, and a tendency to move away from the coastline
to higher ground, and even towards ocean cages. Most
farms produce at least two crops per year, although
some farms can reach or surpass four or more annual
crops, particularly those using nurseries or multi‐phase
production systems.

Early on, when the industry was young, farms were
mostly extensive, and there are still many such farms
in Thailand, Indonesia, India, Vietnam, Bangladesh,
Central and South America, among other countries.
Since around 1980, however, there has been a trend
towards refitting farms to increase intensity of pro­
duction. The more intensive farms are more typical
in countries such as Taiwan, Japan and the USA (Jory
et al., 2001).

504 Aquaculture
Table 22.1  Various shrimp farming systems, based on stocking density, production inputs and operational parameters. PL, postlarvae.

Intensity

Parameter Extensive Semi‐intensive Intensive (high density) Intensive (very high
Stocking density (PL/m2) (low density) (medium density) density)
Pond/tank area (ha) 26–120
Seedstock source 1–5 5–25 Ponds/tanks (0.1–5.0) 120–500
Water exchange (% daily) Ponds (5–100) Ponds (1–25) Hatchery Tanks (0.1–1.0)
Wild Some wild/mostly hatchery Pumping Hatchery
Management Tidal (ca. 5%) Pumping (up to 25%) Pumping (25%+)
requirements (5–10%) High
Feed Minimal Moderate Very high
Natural productivity /
Fertilisation Natural productivity Natural productivity and mostly formulated feeds Natural productivity /
Mechanical aeration formulated feeds Sometimes mostly formulated feeds
No Generally yes Mechanical aeration Sometimes
Aeration levels (hp/ha) No, minimal water Water exchange and some Mechanical aeration
Production cycle (days) exchange mechanical aeration 6–20
Annual production 0–2 2–5 80–140 20–60
(kg/ha) 100–210 100–210 5000–20 000 80–120
50–500 500–5000 20 000–40 000

Figure 22.6  Water pumping station for a
shrimp farm. Farms in Latin America tend
to operate with greater volumes of water
exchange than their counterparts
elsewhere. Source: Reproduced with
permission from Darryl Jory.

22.3.1  Extensive Systems (Low Stocking involve polyculture with herbivorous fishes such as
Densities) mullet, milkfish, tilapia and others. At some of these
Shrimp farms with low stocking densities are typically farms, liming materials are sometimes applied to ponds
located in tropical water impoundments ranging from if soils are acidic or have accumulated considerable
ca. 2 ha to > 25 ha and are located adjacent to estuaries, amounts of organic matter that is not removed. Some
bays, and coastal lagoons and rivers. They frequently operations may sometimes use animal manures or other

organic materials to stimulate production of natural food Shrimps 505
for their shrimps (Ponds are filled by tides and any water
exchange (typically < 5−10% per day) is also by tidal Subsequently, there is variation in the degree of
action. Ponds are typically stocked with wild shrimp dependence on formulated feeds. Dependence on formu­
postlarvae (PL), when naturally available, by opening lated feeds is not as great at this moderate density as it is
pond gates to incoming tides. at higher culture densities; hence, in the continuum of
culture practices, this is semi‐intensive culture.
In all cases, these shrimp feed on natural phyto‐ and
zooplankton, small plants and animals living in or on the 22.3.3  Intensive Systems (High Stocking
pond substrate (particularly amphipods and poly­ Densities)
chaetes), and particulate organic matter suspended in
the water or lying on the bottom. This natural produc­ Shrimp farms using intensive culture and high stocking
tion may be promoted with applications of organic or densities (Table 22.1) typically have ponds of 0.1–2 ha,
chemical fertilisers. In this extensive aquaculture the cul­ although various designs of raceways and above‐ground
tured shrimps are essentially part of a natural ecosystem tanks are also used, sometimes in greenhouses or hard
that provides their nutritive and other requirements. buildings. Ponds are frequently lined with (high‐density
Construction and operating costs are typically low, and polyethylene) HDPE or other commercial, plastic, inert
production rarely surpasses 400–500 kg/ha in produc­ liners. Preparation before stocking is more meticulous,
tion cycles that last 100–160 days. Because it is ille­ and management is often more elaborate, with feed
gal – and inefficient − in several countries to build new applied 6–24 times a day. Mechanical aeration is abso­
shrimp farms in tidal and mangrove areas, very few new lutely necessary to support the large shrimp biomass
extensive shrimp farms are being built anymore. (and in some cases, liquid oxygen – LOX − is required)
and heavy feeding rates needed. Aerators and/or air‐
22.3.2  Semi‐Intensive Systems diffuser systems are placed in ponds and operated
(Medium Stocking Densities) throughout the cycle, usually with increasing number of
units and longer hours of operation as the cycle pro­
Shrimp farms that operate at medium stocking densities gresses. Generally, 4–12 hp/ha is used, with the amount
(Table 22.1) are built above the high‐tide line and include increasing as the biomass of shrimp increases (Table 22.1).
a pumping station, water distribution canals. reservoirs These systems are often stocked with juveniles from
and use of formulated feeds. In general, farm layout is nurseries, rather than with postlarvae.
relatively more symmetrical than extensive farms and
ponds are harvested by draining through a net or by 22.3.4  Intensive Systems (Very High
using a harvest pump. Pond preparation may be elabo­ Stocking Densities)
rate, with dry‐out once or twice a year, tilling and liming
with various liming materials, and fertilisation with N, P, At the upper end of the continuum, systems with very
Si and other compounds to promote natural production. high stocking densities (Table 22.1) include the highest
Producers may also apply various extracellular enzyme level of environmental control, to the point of some
preparations and bacterial inocula to improve water being located indoors in greenhouses and other struc­
quality, but the benefits of these treatments remain to be tures. Annual production can reach 20–100 t/ha and
conclusively established. Organic fertilisers (mostly higher, but there are currently only a few of these farms,
manure and agricultural by‐products) are sometimes mostly in various Asian countries. Examples of these
used. In recent years, many farmers have adopted advanced farms and technology include the pioneer
exchange practices of 2–5%. These lower exchange rates operations by (still ongoing) Belize Aquaculture Ltd
reduce pumping costs, and minimise fertiliser needs and (BAL) in Belize and (the now closed) OceanBoy Farms
the possibility of pathogen introduction. Formulated and in Florida, USA. Pond management at these farms was
pelleted feeds with 15–35% crude protein are usually designed to be based on zero water exchange, heavy
applied 1–3 times per day, typically by manual broad­ aeration (up to 60 or more hp/ha) and the promotion of
casting over pond surfaces from boats and levees. Feed a bacteria‐dominated and stable ecological system.
quantity applied is calculated and adjusted based on This compares with the highly unstable and traditional
the shrimp biomass estimated from results of cast net phytoplankton‐dominated system typical of semi‐
sampling and feeding charts typically provided by feed intensive systems. The feeding regime used promotes
manufacturers, and also from historical data collected the growth of heterotrophic bacteria and essentially
at each farm. Natural productivity in the ponds is makes the pond into a large outdoor bioreactor, akin
important for juvenile shrimp growth during the early to a sewage oxidation pond. In these high‐density,
weeks at all intensities of shrimp culture. zero‐water‐exchange systems, the pond ecology shifts
(at weeks 9 to 10 after stocking) during the production

506 Aquaculture lime. Once the soil is moistened, the pH will rise to 12 or
more within days and then gradually return to normal as
cycle from an autotrophic phytoplankton‐based com­ the quick lime transforms to calcium carbonate.
munity to a heterotrophic bacteria‐based community.
This shift improves water quality through fast digestion After a production pond is harvested, all water inlet/
(oxidation) of organic waste without production of outlet gates are opened to generate a strong water flow
toxic metabolites; and also recycles wastes into nutri­ through the pond, to re‐suspend and flush out as much
tious bacterial flocs, the basis for ‘natural production’ in accumulated sludge as possible. The use in the ponds of
this system. probiotics that help digest organic matter in situ during
the culture cycle can help alleviate the amount of
22.4  Preparation of Ponds65 organic matter that remains after a production cycle.
And careful management of aquafeeds, with more feed
General details of ponds, site requirements, layout, design applications per day, typically also helps with organic
and water turnover are given in Chapter 4. For a review of matter management.
pond preparation and management, see Boyd et al. (2010)
22.4.2  Pond Drying and pH Mapping
Adequate pond preparation provides young shrimps
with an environment that is relatively free of predators and Earthen ponds must be allowed to dry out for 2–4 weeks
competitors, with an ample supply of adequate natural food to promote decomposition of organic matter by bacteria;
organisms, and environmental conditions that minimise eliminate pathogens and eggs, larvae and adults of
stress and promote growth and survival. Pond preparation predator and competitors; and dry out undesirable fila­
involves several sequential procedures, including: mentous algae.
1) pond draining and drying;
2) pH mapping; The rate of organic matter decomposition is greatest at
3) soil tilling; a soil pH of 7.5–8.5 and, for ponds built on acidic soils,
4) disinfection and liming; farmers add various lime products to improve soil pH
5) fertilisation; and and promote decomposition of organic matter.
6) weir gate preparation and maintenance.
The first four steps above are not necessary in the case of Optimal microbial action for decomposition of organic
fully‐lined ponds. matter occurs at about 20% soil humidity. Pond dry‐out
and disinfection may be the most effective methods for
22.4.1  Pond Draining and Sludge Disposal controlling epidemics of various shrimp pathogens, as
Effective removal of sludge that has built up on the pond well as various predators and competitors. UV radiation
bottom over a prior crop cycle is a very important step. If (via sunlight) and temperatures above 55°C will destroy
not removed, it will become an anaerobic, reduced sedi­ several pathogens. If diseases have been detected within
ment. This will generate toxic metabolites such as meth­ the last production cycle, a longer dry‐out (2–3 months)
ane, hydrogen sulphide, ammonia, nitrite, ferrous iron, may be helpful. The pond surface must be cracked to a
etc., affecting pond water quality and production during minimum of 5 cm, to oxidise the soil and eliminate
the following crop cycle. Organic sludge is a very impor­ anaerobic conditions. In acidic soils with pH ca. 7, pond
tant factor for the onset of EMS, as a substrate for the bottom pH must be mapped promptly by sampling soil
pathogenic Vibrio parahaemolyticus that causes this pH at various stations within the pond while soil humidity
most important, devastating and recent disease. With the is about 30%, to calculate lime requirements. Once the
advent of a relatively new shrimp disease, EHP (acronym pond surface is hard enough to walk on, soil pH is
for a disease named after Enterocytozoon hepatopenaei, a measured using standardised procedures.
tiny microsporidian parasite that affects shrimps by
disrupting their digestive systems), it is very important to Ploughing or turning the bottom soil of ponds (top
properly disinfect earthen ponds with calcium oxide 10–20 cm) is another optional step, which will depend
(CaO, quick lime), applied at 7 t or more per ha over com­ on soil condition. Tilling the bottom soil of ponds can
pletely dry bottoms. The quick lime should be ploughed significantly promote oxidation of the lower layers of
into the dried sediments to a depth of 10 to 12 centime­ anaerobic sediments. Probiotics are sometimes also
tres and then the sediments moistened to activate the added to help digest organic matter.

6  There are further details of water quality and its management 22.4.3 Disinfection
in Chapter 4.
Disinfection is important to eliminate eggs, larvae, juve­
niles and adults of species of fish, crustaceans, insects,
and other predatory and competitor species. Several
commercial products have been used to disinfect ponds

Shrimps 507

before stocking shrimps. The use of pesticides (particu­ ●● for pH 5.5–5.0 (3000 kg/ha); and
larly chlorinated hydrocarbons and organophosphates) ●● for pH < 5.0 (4000 kg/ha).
is not recommended.
22.4.5  Weir Gate Preparation and Entrance
Applying calcium oxide or calcium hydroxide at 5000 Screening
kg/ha will raise the pH to greater than 10 and will destroy Configuration and placement of weir gate restriction
pathogens. Only muddy areas must be treated like this, boards and screens to prevent escapes and entry of pred­
not the entire pond bottom, as this process will destroy ators, while at the same time allowing water to enter and
desirable bacteria needed to promote the development exit continuously, is vital for cost‐effective production.
of productive benthos. Piscicides (fish‐killer) such as
rotenone and teaseed cake are routinely used to eliminate Very fine (200–250 µm) screens are installed in the
finfish, including mudfish. inlet structure to initially fill ponds. When pond filling is
complete, these filters are replaced with 300‐ to 500 µm
22.4.4 Liming screens. Bag net filters are used in the inlet structures to
augment effective filtering surface area, and reduce
Liming pond bottoms is a critical step in preparing screen clogging. Bag net filters of 2–5 m in length are the
earthen ponds. When calculating liming requirements, best, but there is no limit to the length or size of the bag
the type of lime product to use must be considered, as net filter and, in general, the longer the better. Multiple
this will influence the amounts required (Table 22.2). One bag configurations (where a filter bag is placed inside
lime application is generally added 2 days after tilling with another) are a cost‐effective means of decreasing the
lime spreaders, applying lime more heavily to wet low mesh aperture size without installing a finer screen.
areas than to higher dry areas. One week is allowed for Ponds are inspected for proper completion of necessary
the lime to react with the soil before applying fertiliser. preparation steps before filling with water.
The calculated neutralising values of various compounds
used in pond liming range from 59% (sodium bicarbo­ 22.4.6  Natural Productivity
nate) to 208% (calcium magnesium oxide) (Table 22.2).
Proper management of natural productivity in shrimp
When liming requirements cannot be calculated, the ponds is critical to promote and sustain plankton blooms,
following liming rates, using calcium carbonate, CaCO3, and microbial and benthic community productivity.
can be used (see also Chapter 4): A vigorous phytoplankton bloom will support a healthy
benthic community and will contribute significantly to
●● for pH 6.5–7.5 (500 kg/ha); stabilising and maintaining adequate water quality in
●● for pH 6.0–6.5 (1000 kg/ha); shrimp ponds. This happens:
●● for pH 5.5–6.0 (2000 kg/ha);
●● by promoting oxygen production through photo­-
Table 22.2  Neutralising values of various compounds used synthesis;
in pond liming (Boyd et al., 2010).
●● by decreasing levels of various metabolites and toxic
Compound Chemical name Neutralising substances;
value (%)
Agricultural Calcium carbonate ●● by improving pond water and bottom pH (critical in in
limestone 100 ponds with acid‐sulphate soils);
Agricultural Dolomite
limestone 109 ●● by limiting, through shading, growth of filamentous
Burnt lime Calcium oxide bottom algae; and
Burnt lime Calcium magnesium 179
oxide 208 ●● by increasing turbidity which reduces bird predation.
Hydrated lime Calcium hydroxide
Hydrated lime Calcium magnesium 135 Natural productivity is also important because it sup­
hydroxide 151 ports the generation of detritus, the particulate organic
Soda ash Sodium carbonate material produced from the dead bodies, non‐living
Baking soda Sodium bicarbonate 94 fragments and excretions of living organisms. In
Other compounds Calcium silicate 59 nature, organic detritus is an important food source for
Other compounds Calcium phosphate 86 many estuarine organisms, and in shrimp ponds it can
65 have an important role. Shrimp feed on detritus, and
derive nourishment by stripping the micro‐organisms
from the detritus as it passes through their gut.
In addition, their faecal pellets may be recolonised and
the process repeated until all the organic material has

508 Aquaculture these fertilisers can be problematic in some places due to
its other potential uses as explosives. An N/P ratio of
been utilised. By maximising the recycling capability of 15–20:1 promotes the development of diatom blooms;
organic detritus within the culture environment, nutri­ however, the N/P ratios used in many shrimp farming
tionists and pond managers have an opportunity to areas worldwide can vary from 1:1 up to 45:1.
reduce feed and production costs, improve FCR, and
reduce environmental impacts.

22.4.7  Initial Fertilisation 22.5 ­Reproduction and Maturation

Fertilisation of shrimp ponds is an effective means of 22.5.1  Hatchery Production and the Life Cycle
stimulating natural food production that can help reduce
feed costs. Through fertilisation, managers can promote The typical life cycle of a shrimp in nature begins with
those pond ecosystem components that are beneficial to adult animals migrating up to several kilometres off­
shrimp production and discourage those that are detri­ shore, maturing, mating and spawning. The eggs initially
mental. Several organic and inorganic nutrient sources sink, but after a few hours they hatch and the nauplii (the
can be used to fertilise shrimp ponds (section  4.4.2). first larval stage) float to the surface. Shrimps usually
They vary in their effectiveness because of differing spawn in areas where favourable currents will eventually
nutrient density, solubility in water, potential toxicity, bring the developing larval stages inshore into nursery
C/N ratios and other factors. Appropriate fertilisation areas such as estuaries, large bays and coastal lagoons.
rates vary depending on fertiliser type and the ambient These areas provide abundant natural food and adequate
nutrient concentration in the water. Various dynamic conditions for survival and growth. Developing shrimps
processes in ponds can also affect fertilisers, producing remain in nursery areas for several months, and then
dissolved nutrient concentrations after fertilisation that begin maturing and moving offshore to spawn and com­
may substantially differ from calculated concentrations. plete their life cycle (Figure 22.7).

Fertilisation involves the application of fertilisers over Hatcheries in the western hemisphere (for L. vannamei)
the entire pond bottom before filling with water. The are typically large (Figure 22.8), often belong to a verti­
objective of inorganic fertilisation during preparation cally integrated operation that includes a grow‐out farm
and during the grow‐out cycle is to promote and main­ and a processing plant, and they frequently produce
tain population densities of diatoms and green microal­ excess nauplii that are sold to smaller hatcheries, or post­
gae of at least 80 000–100 000 cells/mL larvae that are sold to other farms. Many of these operate
on two larval culture phases, stocking 100−250 nauplii/L,
There is no universally optimal N/P ratio, and each transferring from first to second phase at PL7(instar 7),
farm must determine by trial and error the most suitable and harvesting at PL12‐14. This western hemisphere
inorganic fertilisation regime for its prevailing conditions hatchery model has been transferred and adapted to
and needs. In areas that have markedly different dry and Asia with the introduction of L. vannamei there. In the
wet seasons, there are different optimal fertilisation ratios eastern hemisphere, many backyard and medium‐scale
for each season, as well as different optimal stocking hatcheries are used to produce most of the seedstock
densities and other significant management differences. used by farmers. However, in the past 12 years or so, very
large hatcheries have also started operating in Asia, often
When selecting inorganic fertilisers, the type (nutrient as part of integrated operations. Some have very sophis­
class, composition and solubility), the N/P ratio, daily ticated genetic improvement programs.
dose rates and frequency of application must be consid­
ered. The main nutrients needed in shrimp ponds to Larval development from egg to PL is complex and
promote phytoplankton blooms are N, P and Si. Si involves three stages: nauplius, zoea and mysis. The
compounds stimulate production of the very desirable nauplius has five or six sub‐stages, and the zoea and
diatoms, the cells of which are enclosed in an Si com­ mysis generally have three sub‐stages each, with each
pound. However, Si fertilisation is rarely needed at water sub‐stage lasting few to many hours. The larval develop­
salinities over 25‰ or so. The most common silicate ment process takes ca. 15 days. As larvae develop and
fertiliser used is sodium metasilicate, which is expensive consume the yolk sac, their diet switches to phytoplank­
and not widely available. Commonly used inorganic ton and then to zooplankton. After the mysis stage, they
fertilisers are urea and sodium nitrate as N sources, consume a variety of organisms, including brine shrimp
and monoammonium phosphate (MAP), diammonium (Artemia species). All these live organisms are produced
phosphate (DAP) and triple superphosphate (TSP) as P in the hatchery (see Chapter 9), but major advances have
sources. Urea is the most commonly used source of N been made recently to develop alternative inert diets
because it is widely available, inexpensive and effective. (section  9.4), including synthetic Artemia. After they
Nitrate‐based fertilisers are very effective, but more
expensive and less available, and purchasing and possessing

Shrimps 509

Figure 22.7  A broad outline of a shrimp PRODUCTIVE
life cycle. Source: Reproduced with SHALLOW
permission from Darryl Jory. ENVIRONMENTS,
e.g.,
MANGROVES Larval stages nauplius larvae
through Eggs
Post- development
larvae

Juveniles

Adults mature Females
and mate spawn eggs

Subadults

Figure 22.8  Large tanks for rearing
shrimp larvae in a commercial hatchery in
Latin America. Source: Reproduced with
permission from Darryl Jory.

become PL, the animals look like small adult shrimps 22.5.2  Broodstock Maturation
and are able to feed on zooplankton, detritus and It is very important to be able to produce seedstock
commercial feeds. After several days as PL, they are on demand, consistently and in sufficient numbers to
ready to be stocked into nursery or grow‐out systems. support the industry. Maturation of shrimp broodstock
With the increasing importance of genetic improvement is undertaken routinely in many countries, and at least
programs to address biosecurity concerns for various 26 penaeid shrimp species have been matured and
shrimp diseases, hatcheries will play an increasingly spawned in captivity to produce viable eggs. However,
important role in the support and expansion of the the life cycle has only been closed consistently and
industry. For detailed information on hatchery proce­ dependably for a few shrimp species.
dures refer to Juarez et al. (2010).

510 Aquaculture in the polyunsaturated long‐chain fatty acids (PUFAs)
that are essential for shrimps to mature, and the worms
Large hatcheries typically have separate infrastructure are commercially available. Using natural, live or fresh
to carry out broodstock maturation. The maturation feeds can create serious biosecurity concerns, and it is
section of a hatchery is normally isolated from other likely that some major shrimp diseases have been widely
sections, to reduce noise levels and stress caused by spread due to careless practices.
human activity. Maturation tanks are typically round,
about 3–5 m in diameter and 60–100 cm in height, and 22.5.5  Mating and Spawning
they are gently sloped towards a central drain to facilitate Mating in shrimps is characterised by particular court­
removal and siphoning of uneaten food and other unde­ ship behaviour, and various pheromones are involved
sirable debris. in sex attraction. Females with one or both eyestalks
ablated (removing glands that affect ovary develop­
Environmental conditions in maturation facilities ment) will normally spawn multiple times over a period
duplicate or even intensify conditions known to stimu­ of several weeks. Nauplii can be collected directly from
late reproduction. Each species has optimum ranges at maturation tanks, but in most commercial operations
which maturation will be facilitated. The value of these mated females are usually removed and placed in indi­
parameters and their rate of variation over time are criti­ vidual spawning tanks of 100–500 L. This is particularly
cal to stimulate the reproductive process. The water sup­ important in operations implementing selective breeding
ply system, closed or open, must continually provide programs.
maturation tanks with clear unpolluted water with oce­
anic characteristics and a daily exchange capacity of 22.6 ­Hatchery Design and Larval
200–300%. Many hatcheries now use a recirculation Culture
water system for broodstock operations. Optimum water
temperature for maturation is typically around 28–29°C. 22.6.1  Hatchery Design
An oceanic salinity of 30‰ is considered optimum, Shrimp hatcheries may be set up in a warehouse struc­
although maturation may occur between 28‰ and 36‰, ture or building shell and have indoor and outdoor infra­
and pH must be maintained between 8.0 and 8.2. structure and facilities. Hatchery design follows the
typical pattern with various areas for microalgae culture,
22.5.3  Open vs. Closed Thelycum Species laboratory, brine shrimp production, seawater treatment
and holding, spawning, larval and PL rearing. Support
Penaeid shrimps belong to two groups based on the infrastructure includes storage space, offices, and aera­
structure of the female thelycum, a receptacle structure tion and electrical power generating capability. There are
on the ventral thorax of females where the spermato­ small, medium and large shrimp hatcheries, and all have
phore is deposited by the male at mating. The manage­ the same basic infrastructure:
ment of maturation procedures is different for open‐ and ●● Small hatcheries are usually a family operation, with
closed‐thelycum species
very low set‐up and operating costs, using simple tech­
22.5.4  Maturation Procedures niques and untreated water, low culture densities, and
with larval culture tank capacity under 50 000 L. These
The maturation process is relatively simple and includes generally produce either nauplii or PL, and often suffer
selecting or sourcing good prospective broodstock disease outbreaks and water quality problems.
(screened for absence of viruses) and holding them under ●● Small‐ and medium‐scale hatcheries are usually based
stable, optimal environmental conditions, minimal stress on the Taiwanese design; with large culture tanks
and adequate nutrition using both natural and artificial between 5000 and 50 000 L.
diets. Exclusion and control of opportunistic shrimp ●● Large hatcheries use elaborate techniques to operate
pathogens, such as various bacteria, fungi and proto­ controlled culture environments (Figure  22.9). They
zoea, is critical. It is accomplished by maintaining the target annual production of 100 million PL or more
best water quality possible and by periodic prophylactic and are typically based on the ‘Galveston’ system.
treatments. When large hatcheries have water quality and disease
problems, they can require several months to get back
Adequate nutrition is another factor critical for on line.
shrimp maturation, promoting sexual maturation and
mating, and improving fertility and offspring quality.
Maturation diets typically include combinations of com­
mercial dry and semi‐moist pelleted feed supplements,
together with natural organisms such as various molluscs
(clams and other bivalves, squid), crustaceans, fish and
‘bloodworms’. Bloodworms are marine polychaetes rich

Shrimps 511

Figure 22.9  Large outside tanks for
rearing shrimp postlarvae (PL), Brazil.
Source: Reproduced with permission from
Darryl Jory.

22.6.2  Larval Culture Methods Several species of microalgae are commonly produced
Worldwide, various methods are used to produce shrimp in shrimp hatcheries, including species of the genera
larvae in hatcheries. These are all modifications of the Tetraselmis, Isochrysis, Chaetoceros, Skeletonema and
two basic methods, the Taiwanese and the Galveston others. Isochrysis galbana and Chaetoceros gracilis are
methods. The latter is a modification of the former and among the best, because of their relatively small size and
differs from it in that microalgae are cultured outside the significant content of highly unsaturated fatty acids
larval tank and are added as required. Over the years, (HUFAs). It is common to enrich brine shrimp nauplii
many researchers have helped modify and refine these with HUFA before feeding these to larval shrimp.
techniques.
See also Chapter 9.
22.6.3  Larval Nutrition
The larval feeding regime of shrimp hatcheries is typi­ 22.6.4  Probiotics, Vaccines and
cally based on microalgae and brine shrimp or on live Immunostimulants
feeds combined with formulated/prepared diets. The lat­ The ability to control pathogenic organisms, particu­
ter can be produced at the hatchery, although in recent larly bacteria, has been very important to the suc­
years several commercial brands have become available. cess of commercial‐scale hatcheries. The general
Most are ‘dry diets’ packaged under vacuum or in nitro­ method to control pathogenic and undesirable bacte­
gen‐filled cans or pouches, and others are ‘liquid diets’ ria is through various water filtration and disinfection
and are produced in a range of particle sizes suited to the techniques (e.g., UV, chlorination). Other common
feeding habits of the larval stages for which they are procedures include hygienic procedures (personnel
intended. Crude protein levels typically range from 42% and equipment disinfection) and the use of non‐
to 48%, whereas lipids are 12–16% and fibre is less than infected cultures of microalgae and brine shrimp. Use
5%. Artificial diets are not a complete replacement for of antibiotics can result in development of resistance,
natural food, but when used supplementary to natural chemical traces in shrimp tissues, and environment
food they can increase both survival rate and growth impacts.
when compared with the feeding of natural diets (algae
and brine shrimp) alone. It is likely that in the near future Probiotics are widely used to promote survival and
these dry and liquid inert diets will totally replace live growth of larval shrimps, and can be an effective hatchery
feeds in hatcheries, with major savings in costs and tool by:
resources. ●● competitively excluding pathogenic bacteria;
●● producing substances that inhibit growth in oppor­

tunistic pathogen species;

512 Aquaculture promote acceptable survival and production. Of particular
importance, in the case of outdoor ponds, is that there
●● providing essential nutrients; is sufficient natural productivity to provide adequate
●● promoting digestion by supplying essential enzymes; nutrition to the animals being stocked. There is a window
of about 10 days, starting about 10 days after pond filling
and begins, when pond conditions should be adequate for
●● direct uptake of dissolved organic material mediated stocking. In general, ponds should not be stocked beyond
20 days after filling has begun.
by bacteria.
There is much potential for improvement of probiotics, Seedstock of great quality may be severely stressed
but more research is needed to identify suitable species by inadequate water quality or high packing densities
and how to promote their population growth in larval during the move from hatchery to farm. Inadequate
culture tanks. packing and transportation of shrimp seedstock will
significantly affect survival and health. Care must be
22.7 ­Seedstock Quality and Stocking taken to minimise stress and to provide the best handling
and conditions possible.
22.7.1  Seedstock Packing, Transportation
and Reception Methods of packing and transportation of shrimp
It is important that the delivery of seedstock (PL) is well PL can vary significantly, depending on origin, species,
co‐ordinated between the hatchery and the farm. Good distance between hatchery and farm, resources
planning and communication are required to ensure a available and other factors. PL are typically trans­
smooth transition from the protected conditions of a ported to farms from hatcheries in plastic bags with
hatchery to the conditions of an outdoor pond, tank or water and added oxygen, within polystyrene foam or
raceway (Fig. 22.10). Timing is critical to ensure that the cardboard boxes and cooled to 18–22°C (down from
PL are going into a grow‐out environment that has been the typical 28–30°C in hatchery larval culture tanks);
adequately prepared and has the proper conditions to or in 2−20 t tankers set up to provide water aeration /
oxygenation.

Feed (e.g., frozen brine shrimp or inert commercial
diets) is added to prevent cannibalism. Packing densi­
ties vary between 500 PL/L and 2000 PL/L, depending
on species, age and estimated time in transit. When
possible, PL are transported early in the morning or in
the evening, to avoid high temperatures. Transport
time should be as short as possible, ideally not exceeding
6–8 h. Reduced water temperature and use of various
compounds to shipping water (including ammonia
suppressants, buffers and activated carbon) increase PL
survival over extended shipping.

Upon arrival, parameters such as water temperature,
salinity, dissolved oxygen, pH and alkalinity must be
determined to serve as the baseline for acclimation
adjustments to match pond water characteristics.

Figure 22.10  Shrimp postlarvae held up for inspection. Source: 22.7.2  Counting and Quality Control
Reproduced with permission from Darryl Jory. There are various methods used to count shrimp PL and
there is controversy regarding the accuracy of each.
Volumetric subsampling is the most common technique:
it involves concentrating all or most of the PL in a known
volume of water and drawing a fixed number of sub­
samples (around five) using a beaker or similar container
of known volume. The subsamples are counted and their
average is extrapolated to the larger volume. Nowadays,
there are also commercial, video‐based counters available
that use computer image recognition and can count PL
in real time.

Stocking only the best‐quality shrimp PL is critical to Shrimps 513
the success of a shrimp farm. Although many hatcheries
will provide health certificates for their PL, it should be 22.8 ­Production Management
compulsory for the farm to carry out its own testing. and Harvest

The strength or ‘hardiness’ of PL from different hatch­ 22.8.1  Water and Sediment Quality
eries or batches can vary significantly and the acclimation Some water quality parameters must be routinely moni­
schedule must be tailored to the PL ‘fitness’. Stronger tored to effectively manage shrimp production systems
animals can be acclimated at a faster rate than weaker PL. during grow‐out. Controlling various parameters can be
Various stress tests are used to challenge PL and determine difficult, but, if not managed properly, pond carrying
a suitable acclimation schedule. capacity can be rapidly exceeded and ponds can crash
within a few hours or days. Monitoring the quality and
22.7.3  Acclimation and Stocking properties of intake water, pond water/soil conditions
and organics, and other parameters in effluent are essen­
Most shrimp farmers spend substantial resources and tial for good animal husbandry. It is also important for
effort during pond preparation to enable them to stock farms to be environmentally aware and maintain water
their PL into a grow‐out environment with the best management programmes to minimise any potential
possible environmental conditions. These are as free of ‘downstream’ impacts. Table 22.3 shows a general range
predators, competitors and stress as possible, and with and monitoring frequency for various water quality
ample supply of adequate food organisms. Still, the parameters that are important in shrimp production
transition from relatively benign conditions in hatch­ systems. They are measured in the field with probes and
eries to those prevailing in open grow‐out systems, meters or by taking water samples that are analysed in a
such as tanks and ponds, where water conditions con­ laboratory on site. Measurements and samples are taken
tinually or unpredictably change (day/night, dry/rainy at several places within a pond, including the water
seasons over the production cycle) can be a traumatic intake, the central region, drain, and surface and bottom
experience for PL unless the transition is gradual and layers, which provides a more representative assessment
stress is minimised. of the parameter. Detailed information on pond water
parameters, their monitoring and management are
The acclimation station, including all tanks and found in Chapter 4.
other water reservoirs and equipment (nets, siphons,
buckets, tubing, others), is thoroughly cleaned and Table 22.3  General range and recommended monitoring frequency
­disinfected by scrubbing with chlorine or other disin­ for various water quality parameters in shrimp production units
fecting agent. Well‐functioning and calibrated equipment (ponds, tanks and raceways).
to monitor water parameters (temperature, salinity, pH
and DO) before the PL arrive at the acclimation station Minimum Maximum Monitoring
is critical.
Parameter value value frequency*
The typical acclimation process involves holding the
PL for a period in tanks and slowly adding water from Water temperature (°C) 24 30 2–4×/day
the pond to be stocked to equalise various parameters
(mainly salinity and temperature). General acclimation Salinity (‰) 15 45 1×/day
recommendations that have been used for many years DO (ppm) 3 12 2–12×/day
include: pH 8.1 2×/day
Secchi disc (cm) 9.0 1×/day
●● increase/decrease salinity by no more than 3‰/hr; Alkalinity (mequiv.) 30 50 1–7×/week
●● avoid sudden temperature changes (>3–4°C); Total ammonia‐N (ppm) 100 200 2–7×/week
●● maintain DO levels at 6–7 ppm; and Non‐ionised ammonia‐N 2–7×/week
●● acclimation densities should not exceed 300–500 PL/L (ppm) 0.1 1.0
NO3 (ppm) – 0.2 2–7×/week
depending on animal size and duration of acclimation. NO2 (ppm) 1–3×/week
Total N (ppm) 0.6 1.2 2–7×/week
Salinity is probably the most critical parameter to manip­ Phosphate (ppm) – 0.5 2×/week
ulate during PL acclimation. Acclimated PL or nursed PL Silicate (ppm) 2.5 1×/week
may be released into the pond using buckets or other 0.6 0.5
containers at points at least 50 cm in depth, at 50 minute 0.2 4.0
intervals and on the upwind side of the pond to max­ 1.0
imise PL distribution throughout the pond. Excessive
turbulence at release must be avoided to prevent damage H2S (ppm) – 0.1 1–7×/week
to animals.
* depending on production system used and standing shrimp biomass.

514 Aquaculture access to both good‐quality seawater and freshwater can
mix these to desired salinities.
DO is one of the most critical physical parameters of a
pond culture. Low DO is one of the most common causes The pH does not usually reach levels that affect the
of mortality and poor growth in high‐density shrimp shrimps. Values seldom exceed the range of 6–9 in sedi­
ponds. Lethal levels seem to vary from about 0.5 to 1.2 ments or the water column (except in acid‐sulphate
ppm, depending on the species and hardiness of a par­ soils). High pH (>9) is a lesser risk than low pH (<6).
ticular population. DO levels can be relatively unstable Low pH may affect the mineral deposition of the
as a result of wide fluctuations in photosynthetic oxygen shrimp’s exoskeleton after moulting, resulting in ‘soft’
production and the bacterial population affecting BOD. shrimps, and can destabilise some phytoplankton species
DO levels in the water column fluctuates over a day/ that prefer alkaline conditions. pH in the water column
night cycle, from a low at dawn to a high in mid‐after­ fluctuates with phytoplankton photosynthesis and
noon, particularly due to phytoplankton photosynthesis respiration in proportion to dissolved CO2, which is the
during the day and then respiration at night. Hence it is reciprocal of DO. pH is lowest at dawn when dissolved
appropriate to sample DO at dawn and mid‐afternoon. CO2 is highest and highest in mid‐afternoon when
DO readings in the water column immediately adjacent dissolved CO2 is lowest.
to the bottom are essential, because shrimp spend most
of their time feeding and resting in or on the sediment Nitrogenous wastes resulting from protein digestion
(Figure 22.11). can accumulate and even reach dangerous concentra­
tions, particularly at high stocking densities. Nitrite
Salinity and temperature are extremely important and unionised ammonia can accumulate to toxic levels
parameters that affect several biotic and abiotic pro­ periodically, particularly during massive die‐offs of
cesses in the production system environment, but there phytoplankton. Nitrate is usually not toxic at levels
is usually relatively little that can be done to modify typically found in ponds. Total ammonia and nitrate are
them. Water temperature, however, may be controlled in managed through water exchange.
indoor systems of high stocking density. Farms with free
Water transparency is an index of plankton biomass
present and is measured with a Secchi disc, typically
once per day at mid‐morning. Acceptable values are
between 30 cm and 50 cm. Readings of < 30 cm indicate
high phytoplankton biomass or suspended sediment or
both in the water column. Pond water colour usually
reflects the predominant phytoplankton species, i.e.,
golden brown = diatoms; green = green flagellates; blue‐
green = blue‐green algae; and red = dinoflagellates.

Pond sediments tend to deteriorate with successive
cycles and within production cycles due to accumulation
of organic matter and sludge deposition. Sediment
quality can be determined from hydrogen sulphide level
and redox potential (Eh), and by visual examination of
sediment cores. Smelling a scoop of surface mud from
various areas of the pond bottom is a quick check for
hydrogen sulphide sediment. Redox potential of sedi­
ment is another quantitative indicator of sediment con­
ditions. It is a measure of the proportion of oxidised to
reduced substances, and is an indicator of the relative
activity of aerobic and anaerobic bacteria in the sediment
profile.

Figure 22.11  Standing on a plank above the pond with oxygen 22.8.2  Water Management
meter in hand and DO probe down in the water column. Source: Water exchange is an effective management tool to flush
Reproduced with permission from Darryl Jory. out wastes and, in some cases, to improve DO levels.
At many large farms, water exchange often follows a fixed
schedule rather than being a flexible alternative used
when pond conditions require it. High exchange rates
can be wasteful and have a negative effect on fertilisation

and natural productivity by flushing out nutrients. Shrimps 515
As much as 35–40% of pond volume used to be exchanged
daily at many farms some years ago, particularly ponds of DO aims at maintaining DO levels over 4.0 ppm or
stocked at high and very high densities. More typical higher, if possible, throughout the pond, using the least
exchange rates for medium and high stocking densities equipment and with minimum cost. Efficient use of aera­
currently are 2–10%. With the continuing incidence tion and circulation equipment can take advantage of the
of, and increase in the number of shrimp pathogens, a oxygen supplied by photosynthesis during the day and by
significant reduction in water exchange can maximise diffusion across the pond surface at night. Aerators are
biosecurity through the exclusion of pathogens in incom­ the mechanical devices that act as the heart and lungs of
ing water. an aquaculture pond. They provide distinctive circula­
tion and aeration effects, increasing the rate at which
Fertilisation of ponds with inorganic and organic oxygen enters water. There are two main techniques for
nutrients is an effective means of stimulating the pro­ aerating pond water: one is to splash water into the air
duction of natural foods and reducing feed use. In the and the other is for air bubbles to be released into the
first few weeks, it may be necessary to fertilise a pond water, so there are ‘splasher’ and ‘bubbler’ aerators.
every day, then every other day, and eventually biweekly.
Routine fertilisation may be enough to maintain ade­ Shrimp ponds require mechanical aeration when pro­
quate water transparency (30–50 cm), provide a continu­ duction biomass exceeds 2 t/ha and additional aeration
ous natural food supplement and improve water quality. at a rate of around 2 kW for each additional t. The mod­
Once feed applications reach about 25–30 kg/ha/day, no erate circulation effect provided by one or two aerators is
additional N or P fertilisation is usually needed, because desired from the time of stocking. Surface circulation
uneaten feed and shrimp faeces supply enough. Liming must be ca. 4 cm/sec during feed applications. This
compounds are added to ponds in some farms (ca. speed will not disturb fresh pellets, but will keep finer
20–100 kg/ha/week) during the cycle to increase alkalinity, particles and organics in suspension. Excessive water
particularly during the rainy season or in areas where circulation may be managed by arranging aerators in
low‐salinity waters are prevalent. Liming compounds uniform configurations or by other means. In a typical
are also added under the presumption that water quality configuration, aerators generally create a central area of
will be improved and pathogens in the water reduced sediment deposition, and sometimes the sludge depos­
(Figure 22.12). ited may be removed by using suction hoses. There are
central drains in some ponds with high stocking densities.
22.8.3  Water Aeration and Circulation Proper positioning of aerators and circulators is very
Pond aeration is the primary life support system of many important, because their operating efficiency is depend­
aquaculture ponds, including shrimp ponds. Management ent on achieving adequate water circulation.

One of the needs for circulation and aeration is ther­
mal stratification. Thermal stratification can occur in
ponds when surface waters warm faster than deeper

Figure 22.12  Liming shrimp ponds on a regular basis to improve water quality is a common management technique. Source: Reproduced
with permission from Darryl Jory.

516 Aquaculture a series of periodic, serious and financially devastating
diseases, mostly of viral origin but lately also bacterial
waters during the day. This may lead to DO depletion in and fungal. These have probably caused many USD
the bottom water, because most of the DO in pond water billions in financial losses to the industry.
originates from photosynthesis in the upper stratum of
water or by diffusion from the air through the water There are now over 30 distinct viruses (or groups of
surface. Paddlewheel and propeller, i.e., aspirator pump viruses) known to infect shrimps. Viral diseases, particu­
aerators, are especially efficient in circulating pond larly the white spot virus (WSSV) and Taura virus (TSV)
water. There are also circulators that supply little aera­ have severely impacted on the shrimp farming industry
tion but can prevent stratification. These are generally worldwide, causing very important production and
large, slowly revolving (50–150 rpm) propellers installed economic losses.
in ponds to quietly move large volumes of water.
The latest major shrimp diseases affecting the
22.8.4  Population Sampling and Health industry are Early Mortality Syndrome (EMS)(=Acute
Assessment Hepatopancreatic Necrosis Syndrome (AHPND), and
Periodic sampling of shrimp populations is an important Hepatopancreatic Microsporidiosis, known as EHP
management tool during the production cycle. Cast net­ from the small microsporidian parasite, Enterocytozoon
ting is about the only effective sampling tool currently hepatopenaei, that causes it.
available and it is widely used. The process of sampling
has the objective of generating information about a large EMS/AHPND is a serious global disease caused by the
group of individuals, a shrimp population in a pond, by pathogenic bacterium Vibrio parahaemolyticus, which
looking at a small number of individuals. Most shrimp causes hepatopancreas dysfunction and secondary
farms routinely carry out sampling programmes to: Vibrio infections, and can result in up to 100% mortality
●● monitor population size; in juvenile cultured shrimps. AHPND was first reported
●● monitor individual and average size/weight of in China in 2010 and has since spread to other Asian
countries including Thailand, Vietnam, India, Malaysia
animals; and the Philippines, and to Mexico and various Latin
●● evaluate the animals’ physical condition, appearance American countries. Estimated losses due to EMS exceed
USD 1 billion annually. The best management for EMS is
and product quality; to stock clean animals into clean ponds, and to keep
●● assess the animals’ overall health; and organic matter levels as low as possible in the grow‐out
●● test for the possible presence of known pathogens or ponds.

diseases. EHP disrupts the digestive system of affected shrimps.
In the last few years, and as their use becomes wide­ It does not typically result in significant mortalities but
spread, it has been realised that properly managed feed reduces growth and significantly increases size variability.
trays or lift nets can provide adequate population esti­ It has seriously affected farmed shrimp production in,
mates by combining daily feed consumption rates with and has been reported from Thailand, China, Malaysia,
percentage body weight curves. Indonesia, Vietnam and India, and more recently it was
also reported from a Latin American country. Because
Generally, to improve the validity of a shrimp popula­ EHP reproduces through very resistant spores, it is very
tion sampling programme, sample collection must be difficult to eradicate and the most effective management
carried out after lowering the pond water level by practice is strict biosecurity and disinfection of affected
experienced personnel using a large and heavy cast net, facilities.
and the number of sampling stations and frequency of
sampling must be as large as possible. It is important for Several strategies have been tried to control viral
a farm to establish adequate in‐house sampling methods diseases in shrimp farming, ranging from improved
that adequately reflect its needs and capabilities. Dugger husbandry practices to stocking ‘specific pathogen‐free’
and Jory (2016) recently reviewed shrimp sampling. (SPF) or ‘specific pathogen‐resistant’ (SPR) species or
stocks. Further information on shrimp diseases is provided
Health assessment and management on shrimp farms by Cuéllar‐Anjel et al. (2010).
has become an important issue in the last 20 years or so,
because of the increased importance of various diseases, A cost‐effective health management and biosecurity
particularly of viral origin. Shrimp hatcheries, nurseries programme requires reliable diagnostic tools that shrimp
and grow‐out facilities can be affected by many diseases farmers can use to make adequate and timely decisions
of viral, bacterial, fungal or parasitic origin. Some diseases on management procedures to control or exclude path­
are so far only reported from some areas (Eastern or ogens. Virulent pathogens can produce catastrophic
Western Hemisphere). The shrimp farming industry has mortalities very rapidly, and shrimp farmers need this
been characterised through its relatively short history by fast diagnostic capacity in order to respond effectively.
Practical diagnostic methods that are accurate, sensitive,

rapid and economical to conduct are already available, Shrimps 517
including molecular methods like polymerase chain
reaction (PCR), dot‐blot gene probes and various meth­ marketed whole, typically less than 5–8% should be soft
ods for rapid fixation and staining. and less than 15–20% should be semi‐hard. Some farmers
also stop feeding a few days before the harvest, some­
Early signs of many health problems can be promptly times believing this will prevent the condition known as
observed by examining shrimps during regular feed black or ‘exploded’ hepatopancreas.
tray monitoring or from weekly sampling. Some of these
signs include: Most shrimps are harvested by draining the produc­
●● loss of appetite (empty guts); tion ponds, tanks and raceways. In preparing ponds for
●● changes in colour (blueish or reddish); harvest, water levels are typically lowered to ca. 70% of
●● persistent soft shells or shell fouling; their operational levels, beginning 24–48 h before the
●● red discolouration (particularly in appendages and harvest. In larger ponds, it is often necessary to reduce
water levels to 50% or so before beginning the harvest, so
uropods); that the harvest does not last excessively long, which
●● lethargic or disoriented behaviour; would stress the shrimps and reduce their quality.
●● fouled or discoloured or black gills;
●● blackened lesions on shell; Harvested shrimps are immediately separated into size
●● opaque or white tail muscle; and classes and layered with ice or immersed in an ice slurry
●● various morphological deformities, such as cramped for transport to the processing plant. Within minutes
after death, shrimps begin to deteriorate at normal pond
tail. temperatures (25–30°C) that promote bacterial decom­
position. Initial spoilage, however, is due to digestive
22.8.5  Harvest and Transport to Processing Plant enzymes from the hepatopancreas. These break down
Shrimps are highly perishable and delicate, and no proteins and reduce product weight, and quickly break
amount of manipulation can restore product quality down tissue at the junction of the head and tail, making
once it is lost. Therefore, proper preparation, harvesting the head appear loose and sagging, which is unaccepta­
and preservation are critical for the product to be the ble for some markets. Bacterial and enzyme activity can
best quality and command the best price. This prepara­ be stopped by immediately reducing temperature to near
tion can be quite elaborate, because a pond ready to be freezing. It is very important that shrimps are killed by
harvested may have 5−30 t or more of shrimps, which thermal shock when immersed in chilled water (4°C is
must be properly collected, handled and packed. The maintained from the time the animals are harvested to
most important objectives at harvest are to: the time they reach the plant). Often additional process­
●● minimise the quantity of shrimps left on the pond ing takes place at the pond bank. This includes dipping
the shrimps in a solution of sodium metabisulphite to
bottom; prevent melanosis or black spots, and reducing blacken­
●● immediately chill shrimps to near freezing to prevent ing of the head for head‐on shrimp product, removing
crabs, fish and plant material. Shrimps must be handled
deterioration due to bacterial activity; and carefully during packaging to minimise damage to the
●● pack the shrimps in a manner that avoids physical product and thus reducing its acceptability in markets.

damage. Mechanical harvesting systems are also used to harvest
The most important considerations of when to harvest shrimp ponds and assure product quality. These systems
a pond are shrimp size, price and maximising the eco­ can be used to harvest ponds anytime without any tidal
nomic return of the production cycle. Sometimes ponds effects or needs.
need to be emergency‐harvested because of a disease
outbreak. Many shrimp farmers use the moon phase to Further details of post‐harvest technology for shrimps,
program their harvests, targeting periods of full and including safety and health, live transport, post‐mortem
new moon. About 3–5 days before the harvest date, the processing and chilled storage life, are provided in
texture (representative of the stage in the moulting cycle) Chapter 13. A processing plant that operates on a QA/
of shrimps to be harvested is monitored by daily collec­ QC (quality assurance/quality control) is shown in
tion of a sample (100–300 animals/pond) to determine Figure 22.13.
the percentage that are moulting. The particular require­
ments of the processing plant and the intended market Shrimps are marketed in a variety of forms: heads‐on
determine what percentages of hard, soft and semi‐hard shrimps (including live), shell‐on tails, peeled tails
(post‐moulting) shrimps, are acceptable to proceed (including canned) (Figure  22.14), breaded tails and
with a planned harvest. For example, for shrimps to be other value‐added products. These are transported to
various markets in a variety of forms and packaging.
Lucien‐Brun (2016) recently discussed in detail shrimp
harvesting and processing, and the critical decisions and
steps to maintain product quality.

518 Aquaculture

highest production cost. Protein is typically the most
expensive macronutrient in shrimp feeds, and dietary
protein levels from 18% to 50% have been recom­
mended for various species and sizes; possibly because
of their wide range of natural feeding habits. PL
shrimps require a higher dietary protein level than
older shrimps. Formulated shrimp feeds are complex
products and the main components typically are wheat
flour (20–35%), soybean meal (15–45%) and fishmeal
(10−20%).

In recent years, there has been a strong effort to
reduce the inclusion of fishmeal and fish oil, and
replace these with alternative ingredients, including
various meals and oils from agriculture products as
well as rendered ingredients from the processing of
other terrestrial meat industries (section 8.6.5.1). The
remaining ingredients used in typical formulas include
various lipids and micro‐ingredients that provide
essential fatty acids, vitamins, minerals, attractants,
binders, preservatives, pigments and health additives.
At least 150 additives are currently used as ingredients
in shrimp feeds.

Figure 22.13  Shrimp processing plant. Source: Reproduced with 22.9.2  Feed Management
permission from Darryl Jory. Shrimp feed management is a critical aspect for cost‐
efficient, environmentally responsible shrimp produc­
Figure 22.14  Peeled and cooked is a common value‐added market tion. Appropriate practices produce maximum shrimp
form. Source: Reproduced with permission from Darryl Jory. growth and survival concurrent with the lowest FCR,
while reducing feed inputs and minimising impact of
22.9 ­Nutrition, Formulated Diets effluents. Efficient feed management is the summation
and Feed Management of several sequential steps, including feed selection,
storage and handling, application methods, and feeding
22.9.1  Nutritional Requirements and Formulated regimes. Determining when to feed requires knowledge
Diets of diet activity patterns, feeding frequency and time
With industry expansion, there has been an intensifica­ (subject to change with geographical location, season,
tion of production and an increased dependence on the species, size, age, stocking density, unusual environmen­
use of manufactured dry feed, which often represents the tal conditions and other stimuli). Calculating feed rations
involves estimating survival, population size and biomass,
and size distribution. Monitoring and continuously
adjusting the amount of feed applied, according to
changes in consumption caused by various biotic (e.g.,
amount, quality and availability of natural food items)
and abiotic (water quality and other environmental
parameters) factors, is important for effective feed man­
agement. Evaluating and adjusting feed input involves
regular population sampling and proper monitoring of
various water quality parameters.

Shrimps are bottom feeders, and it is difficult to esti­
mate their feed consumption, unless feed trays or lift
nets are used (Figure  22.15). Inadequate feed manage­
ment may promote the onset of various diseases and
water quality‐related problems, and may adversely affect
production. Ineffective practices often include:

Shrimps 519

Figure 22.15  Using a feed tray at set
locations. Source: Reproduced with
permission from Darryl Jory.

●● applying feed during times convenient for employees 4) Moulting. Shrimps moult periodically (days–weeks)
(during daylight hours), but not necessarily at the best throughout their lives, and this is a stressing period
times for shrimps; during which their appetite diminishes markedly.
It  can take 2–5 days for normal feeding to resume
●● inadequate handling and storage practices during after moulting. Thus, it is important to recognise
bulk feed storage and after feed distribution to pond when there is a significant reduction in feed con­
side; and sumption, indicating high incidence of moulting.

●● overfeeding. 5) Quality of commercial feeds. Shrimps eat to fulfil
The best shrimp feed in the world will yield poor results their nutritional needs, and if the feed does not
if it is not handled, stored and used properly. have enough energy or appropriate nutritional
profile, their feeding activity will increase. Feed
22.9.3  Factors that Affect Feed Consumption attractability and palatability are also important
Several factors can affect shrimp feeding behaviour, and factors.
it is important to understand these factors to make
proper and timely management adjustments (Jory et al. 22.9.4  Feed Handling and Storage
2001). The major factors affecting feeding behaviour are: Feed management at a shrimp farm begins upon arrival
1) Species, age and size. There are marked differences of a feed shipment. Poor storage and handling of feeds
will result in product deterioration, reduced feed
between species. Some species are much more active attractability and palatability, possible nutritional defi­
and aggressive while foraging for food, and this has to ciencies and disease outbreaks, reducing growth rates
be incorporated into a feeding strategy. Feeding rate is and overall production. Upon reception of a feed batch, a
a physiological function dependent on the growth few randomly selected bags are examined for physical
stage of the animal; it decreases as the animal grows integrity. In addition, twice a year feed samples are
and approaches maturity. collected from newly received shipments (or when using
2) Availability of natural food. When natural food is a new feed) and analysed for proximate composition,
freely available, the demand for formulated feeds is mycotoxins and selected pesticides if pertinent (Jory
reduced. This is typical when the biomass of stocked et al., 2001; Jory, 2016).
shrimps is low during the first few weeks after stock­
ing and until the natural carrying capacity of the pond Feed is ideally used within the first 2–4 weeks after
is reached. manufacture and must not be stored for more than 2–3
3) Water quality. The most important parameters are months. At farms that feed several times over 24 h, the
temperature, DO, pH and salinity, but other parame­ total feed ration is often distributed from the farm
ters also influence shrimps (Table  22.3). For each warehouse to the ponds once, usually early in the morning.
parameter, animals have a range of tolerance and a The feed bags must then be protected from sunlight
narrower optimum range that promotes optimum and rain by storing them off the ground in simple
feeding, growth and overall well‐being. pond‐side sheds.

520 Aquaculture shrimps – using underwater microphones connected to
computers and using elaborate software programs to
22.9.5  Application and Distribution provide continuous feed applications, if desired.
Formulated feeds may be distributed manually in large
ponds from boats or mechanically using blowers It is important to distribute the feed evenly early in the
mounted on vehicles and boats (Figures 22.16 and 22.17). grow‐out cycle, but, as the cycle progresses, shrimps
In smaller ponds, tanks and raceways, automatic feeders react to changing pond microhabitats. They avoid areas
with timing mechanisms can be used or broadcasting where anaerobic sediments accumulate and noxious
from the pond banks. Feed is applied exclusively using compounds, such as H2S, are produced, including
feeding trays at some farms. Newer and very sophisti­ internal drainage canals and areas close to the drainage
cated auto‐feeding systems rely on the feeding sounds of structures. In addition, many shrimps will move to the

Figure 22.16  A feed blower used to feed
shrimps in large ponds. Source:
Reproduced with permission from Darryl
Jory.

Figure 22.17  Manually broadcasting feed
from a boat or pond bank. Source:
Reproduced with permission from Darryl
Jory.

deeper areas of ponds during the day to avoid light. Shrimps 521
Therefore, it may not be appropriate to apply feed in very
shallow areas during daylight hours, because it is unlikely devices usually consisting of a frame and fine mesh that
that shrimps will consume it. is lowered to the floor of the pond (Figure 22.15) and can
also collect a sample of the shrimps feeding in it. There
22.9.6  Frequency and Timetables are several ways feed trays can be used, including as
All formulated feeds have an ideal feeding rate range indicators of feed consumption, population and health
that optimises growth and feed efficiency. This range assessments and other observations.
varies with species, age and weight, stocking density,
water quality, availability of natural foods, stress and In using the feed trays as indicators of feed consump­
other factors. At many farms, feeding is based on tables tion, about 4−8/ha are used in ponds < 5 ha, whereas
that do not properly consider natural feeding habits of 2−5/ha are used in larger ponds (10–20 ha). A small
shrimps or their physiological state. Increasing the fre­ percentage of the ration is placed in the trays and
quency of feeding generally produces immediate bene­ the  ration is distributed throughout the pond. Trays
fits, including reduced nutrient and feed loss, and are checked after 1−3 hr and the data are used to adjust
increased growth and feed utilisation efficiency. In Asia, rations. In the Peruvian system, the entire ration
it is common practice to feed up to six to seven times is  applied in trays, which requires many more trays
over a 24‐hr period regardless of the species farmed. per pond.

How many times and when to feed is an important In general, observation of feed consumption from a
decision that each shrimp farm must determine, based small number of trays is not an adequate measure of
on the factors described and available resources. Feeding actual feed consumption, especially in large ponds. This
during the night typically becomes more important as is because there are considerable day‐to‐day variations in
the production cycle progresses and the availability of feed consumption.
natural feed diminishes. In general, two feed applications
per day are needed at the beginning of the production 22.10 ­Emerging Production
cycle, increasing as the cycle progresses to at least three Technologies and Issues
or four applications per day.
22.10.1  Diseases and Biosecurity
22.9.7  Feed Rations Viral diseases have had a considerable impact on
Feed rations can be calculated using a set schedule that commercial shrimp farming during the past two decades,
accounts for animal weight and estimated biomass/sur­ significantly affecting the operation, management and
vival in the pond. Feeding based on tables is still widely design of shrimp farms. Another resulting consequence
practised. There are several problems with relying on is increased awareness of the need for better husbandry
feeding tables: methods to reduce the risks of exposure to pathogens,
1) There are problems in accurately estimating survival, and also of the need for improved management practices
to enhance shrimp health. Shrimp farming is a relatively
particularly when dealing with small animals in large new industry and has lagged behind in the development
(ca. 5 ha) ponds. of practices for standard health management. In recent
2) Various factors, as outlined, affect feeding rates. years, tremendous progress has been made in shrimp
Feed consumption changes can usually be detected by health management.
proper monitoring of feed trays. Feeding rates are
adjusted periodically (usually weekly), based on sampling Biosecurity in shrimp aquaculture involves those prac­
estimates for individual average body weight, population tices that will reduce the probability of introduction and
size distribution and pond shrimp biomass. As shrimps dissemination of a pathogen. Shrimp producers often
grow the feed amounts used decrease as a percentage of give only limited attention to routine biosecurity on their
the total shrimp biomass, but the absolute amount of feed farms. This is because of the misconception that the
increases together with increasing shrimp biomass. potential costs of implementing biosecurity measures
will outweigh the benefits or because they do not have
22.9.8  Use of Feed Trays appropriate knowledge. Effective implementation of
Feed trays are also called observation or lift nets, feed biosecurity protocols requires awareness, discipline and
inspection trays or umbrella nets. They are simple a commitment by farm owners to implement them. We
have improved our knowledge of shrimp viral diseases
significantly during the past 30 years, mainly due to their
negative impact on the industry, but more efficient
biosecurity is still very new to shrimp farming (Fegan
and Clifford, 2001).

522 Aquaculture conditions that facilitate growth of pathogenic bacteria.
Microbial management is still a relatively new but most
A cost‐effective, biosecure shrimp‐farming protocol promising field for the shrimp farming industry.
involves:
●● aggressive methods for pathogen exclusion from pro­ 22.10.3  Nursery Systems

duction systems; Many shrimp farms are now using nursery systems as
●● effective screening of seedstock; an intermediate production step between the hatchery
●● appropriate environmental management; and the final grow‐out pond. Nurseries are often also
●● effective health management, integrating genetic used as acclimation stations. These systems can be as
simple as mesh enclosures in smaller, ponds to sophis­
selection; ticated indoor, recirculating systems (lined tanks/
●● specific pathogen‐free and/or pathogen‐resistant ponds in greenhouses or other cover, with areas of
300−7500 m2).
stocks;
●● limited or zero water exchange; Nurseries are used to grow PL at high densities, with
●● stocking strategies; stocking densities from 500 to 10 000 PL/m3, stocking
●● feed management and use of immune stimulants to size of around 2‐mg and harvest sizes of 0.3−3 g and
harvest biomass of 1−3 kg/m3. Nurseries typically pro­
increase host defences; and duce strong, healthy and uniform juveniles with signifi­
●● strict and proactive health monitoring and farm man­ cant potential for compensatory growth after their
transfer for final grow‐out to market size. Nursery systems
agement strategies. have several advantages, including more control and
Also important are farm location (site selection) and efficiency, improved biosecurity and health manage­
design. Relatively few shrimp farms have been specifi­ ment, and they allow for early stocking in areas with
cally designed to prevent diseases, although it is more extreme seasonality.
cost‐effective to incorporate disease prevention and
treatment aspects during the planning stage than to A two‐stage grow‐out system using a nursery phase as
redesign or refit existing farms. Eliminating or reducing a quarantine area increases biosecurity and can increase
water exchange is important to prevent viral diseases, to turnover (number of grow‐out production cycles) by
exclude pathogens from production systems, and to reducing culture time to market size in grow‐out ponds.
minimise stressful variations in water quality, which may Therefore, the grow‐out pond is being used more effi­
trigger disease outbreaks. ciently as a biological system, and with greater capital
and operating efficiency. A nursery system also provides
22.10.2  Probiotics and Microbial improved accuracy to estimate the juvenile population
Management before actual stocking in grow‐out ponds. Thus, stocking
As described, the use of probiotics is relatively common juveniles allows for a more accurate estimate of the initial
to limit pathogenic bacteria in the disease‐prone inten­ population and biomass, and improving feeding rate
sive systems used to produce shrimp PL in commercial estimates when formulated feed becomes up to 60% of
hatcheries. For some time now, the use of bacterial sup­ the production cost. Indoor nurseries can broaden the
plements has been recommended for use in aquaculture temperature stocking windows for seasonal hatchery
ponds to obtain a number of benefits, including: outputs, allowing greater efficiency for the hatchery and
●● reducing blue‐green algae populations; farm. Shrimp farms in areas of lower salinities can use
●● preventing off‐flavour; the nursery as an acclimation system. Nursery head‐
●● reducing N and P levels; start strategies may allow farms without hatcheries to
●● increasing DO; and purchase seedstock in advance of the peak demand peri­
●● promoting decomposition of organic matter. ods, possibly at lower cost and with improved certainty
Several commercial probiotic products are available to of seedstock delivery.
shrimp producers and are widely used with the objec­
tives of promoting shrimp health and shrimp yield; and Managing nursery systems in tanks and raceways is
to manage organic waste and sludge in ponds, tanks and relatively more difficult than standard grow‐out ponds
raceways, as well as pond effluent quality. stocked directly, but the many benefits derived from a
two‐phase grow‐out strategy, using first a nursery system
The pond microbial community plays a major role in (indoor) followed by final grow‐out to market size
the natural food availability, mineral recycling rates and (outdoor pond) can significantly improve production
DO dynamics in shrimp ponds. Effectively managing the and profitability. For a thorough review of shrimp nursery
microbial community can help prevent or reduce the risk systems, see Samocha (2010).
of a disease outbreak, but, if mismanaged, the microbial
community can also promote disease by creating

22.10.4  Inland Shrimp Production Shrimps 523

Shrimp farms have traditionally been built in tropical also considered part of the biofloc community. They pro­
coastal areas, very close to the ocean or to an estuary or vide improved biosecurity, disease prevention, in‐situ
river. Since around 2000, many shrimp farms have been water treatment and nutrient recycling (typically with
developed in inland areas and desert coastlines that, in improved nutrition and FCR). However, these systems
principle, do not appear suitable for this activity. Some of can be expensive to setup and operate, require a high
these farms are located in inland deserts with available degree of technical expertise, and reliable and continuous
underground water having specific chemical characteris­ mechanical aeration.
tics. They could provide a new direction for the expan­
sion of the industry, because deserts and other dry lands In recent years, a number of shrimp farms in Asia and
constitute over 40% of the global land area. Latin America have adopted a strategy of internally
recirculating water and only replenishing from the out­
22.10.5  Recirculation, Biofloc Technology side that water lost by evaporation, seepage and other
and Reduced Water Exchange Systems natural processes. This approach typically relies heavily
on frequent treatment with various bacterial amend­
Improved water management regimes can help address ments, and has numerous advantages:
viral disease problems and issues raised by environmen­ ●● significantly increased biosecurity;
tal groups that have targeted shrimp farming, pressuring ●● minimization of effluents released to surrounding
the industry to adopt more sustainable production
practices. waters;
●● improved pumping efficiency;
Large‐scale application of zero‐exchange and recir­ ●● significantly reduced need for fertilization;
culation technologies on existing farms has already ●● more stable water quality parameters, including
increased producer confidence in the potential for
reducing or eliminating routine water exchange through improved levels of DO;
most or all of the growing season. There are several suc­ and
cessful examples of the implementation of zero‐exchange ●● reduced pond downtime and faster restocking.
production systems. They also has some drawbacks, including:
●● a high initial cost to retro‐fit the ponds, e.g., build sedi­
Browdy et  al. (2001) reviewed various aspects of mentation ponds or convert some existing production
intensive closed technologies for shrimp production. ones into sedimentation ones;
Nutrient‐rich effluents from intensive production sys­ ●● management requires a higher degree of technical
tems can contribute to the eutrophication of receiving competency;
waters, potentially affecting both natural biota and local and
culture operations. Water exchange can be reduced or ●● depending on the shrimp biomass, up to total depend­
eliminated, and supplementary aeration can have an ency on 24‐hr mechanical aeration.
essential role in the successful operation of intensive And in some countries, a number of small indoor facilities
closed systems. Paddlewheel aeration must be increased for shrimp grow‐out have been developed. These
by 10% or more over levels traditionally applied in inten­ depend on buying PL and aquafeed, using small plastic
sive culture to maintain appropriate DO levels. Better swimming pools or small tanks, and they are generally
placement of mechanical aerators and use of back‐up managed as biofloc systems. They are often a side
aeration and alarm systems are also necessary. The ­business to other agriculture activities. They produce
design and management of production facilities to re‐use small amounts of shrimps (50‐400 kg/month), and
water, minimise exchange and eliminate discharge will s­ ervice nearby niche markets for fresh shrimps, fetching
improve the outlook for more profitable and sustainable very high prices for them.
production technologies.
22.10.6 Effluents
Another technology, borrowed from the wastewater General impacts of effluents from coastal aquaculture
industry, that continues to gain strength in shrimp farming farms on marine environments are considered in
is biofloc technology. Bioflocs are masses or aggregates Chapter 5. This is an issue that shrimp producers and
(flocs) of bacteria, algae, protozoans and various forms processors need to address while they are discharging
of particulate organic matter like uneaten aquafeed, effluent.
faeces and others. They are held together in a mucous
matrix secreted by bacteria or by electrostatic attraction Settling basins are especially efficient for treating
or connected by filamentous microorganisms. Animals shrimp farm effluents, because the high concentrations
that consume flocs, like nematodes and zooplankton, are of cations in seawater and brackish water tend to

524 Aquaculture 22.11.3  Disease Prevention, Diagnosis and Control
As described earlier, there have been spectacular collapses
­neutralise the negative charges on suspended clay particles, of shrimp farming industries in a number of countries,
which will flocculate and settle. Plankton cannot be removed including the top producing countries, China, Thailand,
efficiently by sedimentation, and products such as alumin­ Indonesia and Ecuador. Standard denominators among
ium sulphate, lime and selected organic colloids, often the shrimp farming industries of these countries were very
used in wastewater treatment to promote sedimentation, fast, unregulated development and an increased incidence
are not needed in shrimp farm settling basins. of diseases, particularly viral diseases. There are still very
few alternatives to deal with viral infections, and the best
22.11 ­Responsible Shrimp Farming procedure for disease management is exclusion. There
and the Challenge of Sustainability will undoubtedly be new pathogens that the industry will
have to confront and manage. The application of effective
22.11.1  Domestication and Genetic pathogen detection and disease diagnostic methods, par­
Improvement ticularly those based on molecular biology and continu­
During its first three decades, commercial shrimp farm­ ously improved by the industry, are essential to better
ing depended significantly on wild seedstock and brood­ understand and prevent losses due to disease.
stock. Wild seed supply was often unreliable and limited,
and PL shortages severely afflicted the industry. Many 22.11.4  Best Management Practices
factors affected the sourcing of broodstock and wild lar­ Best management practices (BMPs) are a practical way
vae, from global weather phenomena, such as El Niño to approach environment management for shrimp
and annual monsoons, to localised pollution and envi­ farming. They are practices considered the most effec­
ronmental degradation, and over‐fishing or over‐regula­ tive methods of reducing environmental impacts, while
tion of fisheries. being compatible with resource management goals.
Shrimp producers are faced with a variety of major certi­
Shrimps have proved excellent candidates for domesti­ fication schemes and the uncertainty of which one to
cation and genetic improvement, because of their high choose. Some certifications are more important than
fecundity, short generation interval and the presence of others, depending on the targeted export market. It is an
additive effect of genetic variance for growth rate. When urgent matter for the major certification schemes to
compared with most livestock industries, however, come together and harmonise their standards, so that
shrimp farming is still a newcomer to domestication and producers can more cost‐effectively opt for this impor­
selective breeding. tant product quality and marketing tool.

Achieving domestication of selected shrimp species, 22.12 ­Summary
together with selection, genetic improvement and, pos­
sibly, hybridisation and ploidy manipulation, should be ●● Shrimps have been farmed commercially for almost
major research objectives. An industry with the global 40 years. Shrimp farming is now carried out in at least
importance that shrimp farming has achieved cannot 60 countries worldwide, but production is significantly
depend on nature to supply its seedstock reliably. localised in two major areas, Asia and the Americas,
which account for about 95% of all farmed shrimps.
22.11.2  Nutritional Requirements
and Formulated Feeds ●● Production has been increasing steadily in the past
The development and use of compound feeds have been two decades, from about 1 million t in 1995 to about 4
major factors in the expansion of the industry and will million t currently.
continue gaining importance. Growing demand for for­
mulated feeds will increase competition for component ●● It is based mostly on one species with relatively few
resources, particularly fishmeal. There is an enormous selectively‐bred, improved lines. The Pacific white or
but still unrealised potential to reduce the production whiteleg shrimp (L. vannamei) is the most important
cost and improve the nutritional performance of formu­ species in the world, with virtually all production
lated feeds for shrimps. Extensive research must continue coming from aquaculture. This species represents
to improve our knowledge of the nutritional requirements around 75% of all farmed shrimps globally, and over
of shrimps and to develop new diets that are species, area 40% of all shrimps produced in the world (fisheries
and even season specific. Reducing the cost of feeds is an and aquaculture combined).
aspect critical to further expanding the industry and
improving its competitiveness relative to other protein ●● Grow‐out production technology is still mostly exten­
sources, such as fish, beef, pork and poultry. sive to semi‐intensive. There is considerable potential

to improve production efficiency through innovation, Shrimps 525
standardisation and automation at various levels.
●● Knowledge of the nutritional requirements of farmed investors with few proactive alternatives available,
shrimps is adequate but there is much room for other than strict biosecurity measures. This is
improvement. Higher inclusion of land‐based ingre­ because shrimps, being invertebrates, do not have
dients has significantly reduced the use of limited specific immunity and cannot be vaccinated in the
ingredients of marine origin, like fishmeal and fish oil, traditional sense.
which were very important in shrimp feeds during the ●● Ongoing consolidation within the industry both in
first two decades of the industry. Asia and the Americas is creating very large, vertically‐
●● The history of the industry is one of periodic, major integrated companies that can maximise the econo­
disease outbreaks (mostly viral) and continuous mies of scale and efficiency.
health management issues that disrupt supply chains ●● The shrimp farming industry is expected to expand
and markets. It is of major concern to potential significantly in the next two decades, particularly in
India, Southeast Asia and Latin America, and current
production will nearly double by 2030.

References FAO Fishstat Plus (2016). Universal software for fishery
statistical time series. Version 2.30. Fisheries
Alday‐Sanz, V. (Ed.). 2010. The Shrimp Book. Nottingham Department, Fishery Information, Data and Statistical
University Press. Manor Farms, Main Street, Thrumpton. Unit. FAO, Rome.
Nottingham, NG11 0AX, United Kingdom. 920 p.
Fast, A. W. and Menasveta, P. (2000). Some recent issues
Anderson, J.L., Valderrama, D. and Jory, D.E. 2016. Global and innovations in shrimp pond culture. Reviews in
shrimp survey: GOAL 2016. http://advocate.gaalliance. Fisheries Science, 8, 151–233.
org/global‐shrimp‐survey‐goal‐2016/
Fegan, D. and Clifford, H. C., III (2001). Health
Boyd, C.E., C.A. Boyd and Suwanit Chainark. 2010. Shrimp management for viral diseases in shrimp farms. In: The
pond soil and water quality management. Pp. 281–303. In: New Wave, Proceedings of the Special Session on
Alday‐Sanz, V. (Ed.). 2010. The Shrimp Book. Nottingham Sustainable Shrimp Culture (Ed. by C. L. Browdy and
University Press. Manor Farms, Main Street, Thrumpton. D. E. Jory), pp. 168–98. Aquaculture 2001, World
Nottingham, NG11 0AX, United Kingdom. 920 p. Aquaculture Society, Baton Rouge, LA.

Browdy, C. L. and Jory, D. E. (Eds). (2001). The New Wave, Jory, D.E. 2016. The proper management of commercial
Proceedings of the Special Session on Sustainable Shrimp shrimp feeds, parts 1 and 2. http://advocate.gaalliance.
Culture. Aquaculture 2001, World Aquaculture Society, org/the‐proper‐management‐of‐commercial‐shrimp‐
Baton Rouge, LA. feeds‐part‐1/ and http://advocate.gaalliance.org/the‐
proper‐management‐of‐commercial‐shrimp‐feeds‐part‐2/
Browdy, C.L., and Jory, D. E. (Eds). 2009 The Rising Tide,
Proceedings of the Special Session on Sustainable Jory, D. E., Cabrera, T. R., Dugger, D. M., Fegan, D., Lee, P. G.,
Shrimp Farming, World Aquaculture 2009. The World et al. (2001). A global overview of current shrimp feed
Aquaculture Society, Baton Rouge Louisiana USA. management: status and perspectives. In: The New
Wave, Proceedings of the Special Session on Sustainable
Browdy, C. L., Bratvold, D., Stokes, A. D. et al. (2001). Shrimp Culture (Ed. by C. L. Browdy and D. E. Jory),
Perspectives on the application of closed shrimp pp. 104–52. Aquaculture 2001, The World Aquaculture
culture systems. In: The New Wave, Proceedings of Society, Baton Rouge, LA.
the Special Session on Sustainable Shrimp Culture
(Ed. by C. L. Browdy and D. E. Jory), pp. 20–34. Juarez, L.M., Moss, S.M. and Figueras, E. 2010. Maturation
Aquaculture 2001, World Aquaculture Society, Baton and larval rearing of the Pacific white shrimp,
Rouge, LA. Litopenaeus vannamei. Pp. 305–352. In: Alday‐Sanz, V.
(Ed.). 2010. The Shrimp Book. Nottingham University
Cuéllar‐Anjel, J., M. Corteel, L. Galli, V. et al. 2010. Principal Press. Manor Farms, Main Street, Thrumpton.
shrimp diseases, diagnosis and management. Pp. 517–621. Nottingham, NG11 0AX, United Kingdom.
In: Alday‐Sanz, V. (Ed.). 2010. The Shrimp Book. Nottingham
University Press. Manor Farms, Main Street, Thrumpton. Samocha, T.M. 2010. Use of intensive and super‐intensive
Nottingham, NG11 0AX, United Kingdom. 920 p. nursery systems. Pp. 247–280. In: Alday‐Sanz, V. (Ed.).
2010. The Shrimp Book. Nottingham University Press.
Dugger, D.M. and Jory, D.E. 2016. Regular population Manor Farms, Main Street, Thrumpton. Nottingham,
sampling of shrimp in ponds, parts 1 and 2. http://advocate. NG11 0AX, United Kingdom. 920 p.
gaalliance.org/regular‐population‐sampling‐of‐shrimp‐in‐
ponds‐part‐1/ and http://advocate.gaalliance.org/
regular‐population‐sampling‐of‐shrimp‐in‐ponds‐part‐2/