ANS 119: INVERTEBRATE AQUACULTURE PRODUCTION. Common Name Species Metric Tons (2004) Total - marine shrimp 2,476,000

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1 Page 1 ANS 119: INVERTEBRATE AQUACULTURE PRODUCTION Table 1. Aquaculture production of decapod crustaceans. Common Name Species Metric Tons (2004) Total - marine shrimp 2,476,000 Chinese river (or mitten) crab Eriocheir sinensis 415,749 Oriental river prawn Macrobrachium nipponense 213,078 Giant river prawn Macrobrachium rosenbergii 194,159 Monsoon river prawn Marcrobrachium malcolmsonii 245 Freshwater prawns, shrimps nei 28,422 Total - freshwater prawns. 435,904 Indo-Pacific swamp crab Scylla serrata 117,478 Red swamp crawfish 94,978 Swimming crabs, etc. nei 74,625 Marine crustaceans nei 47,436 Marine crabs nei 10,131 Freshwater crustaceans nei 6,269 Portunus swimming crabs nei 774 Red claw crayfish 81 Yabby crayfish 75 Marron crayfish 69 Blue crab 45 Sawtooth caridina 43 Euro-American crayfishes nei 26 Tropical spiny lobsters nei 20 Mud spiny lobster 14 Flathead lobster 5 Noble crayfish 3 Signal crayfish <0.5

2 Page 2 Macrobrachium, the giant river prawn Introduction - Macrobrachium, the name of a large genus (~ 125 species) of freshwater crustaceans, is often used as a common name referring to a single species of freshwater prawn M. rosenbergii which is cultured in many parts of the world both inside and outside of its natural range (Malaysia, India, Thailand). In fact, almost half (213,078 mt of the global production comes from the Oriental river prawn M. nipponense. Aquaculture production of M. nipponense comes entirely from China. The entire Macrobrachium industry can be traced to the work of Dr. Shao-wen Ling (see Ling 1969ab) who in 1961 found the larvae could be cultured relatively easily if brackish water was used. As I heard Dr. Ling relate the story (Keynote Address, WAS 1974), this was discovered as a result of his frustration with continuing larval culture failures and his subsequent habit of offering to the larvae a bit of what ever he had for lunch. One day he sprinkled in a little soy sauce which he was using to season his food and hit upon the essential larval requirement for increased salinity. Interest in Macrobrachium culture in the United States was greatly stimulated by the work of T. Fujimura of the Hawaii Department of Land and Natural Resources in the mid 1960's and early 1970's (see Fujimura and Okamoto 1972). While interest later spread to other parts of the United States commercial culture of Macrobrachium in the U.S. including Hawaii remains limited (see Table 2). Table 2. Total global production (giant river prawn, monsoon river prawn, oriental river prawn, river prawn nei, freshwater prawns and shrimp nei) = 435,904 mt (Fishstat Plus 2004). Top Eleven Countries China India Thailand Bangladesh Taiwan Brazil Malaysia Indonesia Dominican Republic Myanmar Puerto Rico United States Production 340,000 mt 39,000 mt 29,000 mt 17,000 mt 10,000 mt 360 mt 320 mt 290 mt 100 mt 50 mt 40 mt 40 mt

3 Page 3 Broodstock culture - Of the four main crustacean aquaculture candidates, Macrobrachium adults are the most sexually dimorphic. Males generally grow larger (> 200g in the wild) than the females and have a proportionally larger head. Dominant males characteristically have long dark blue chelipeds. Secondary or smaller males in the population have somewhat shorter claws that are more orange in color. The dominant males, "bulls" inhibit the growth and sexual differentiation of the secondary, "bachelors" males. Removal of "bulls" from a population leads to the rapid growth and differentiation of some of the smaller males into new "bulls". Reproductive maturation and spawning of this freshwater prawn is relatively simple. Almost all pairs of reproductively mature Macrobrachium will mate and produce eggs. Ripe females can be recognized by the bright orange color of the ovary which appears brownish through the carapace. Mating takes place within a few hours following a prespawning molt. Spawning occurs then several hours after copulation with the egg mass (up to 80,000 individual eggs) being attached to the first four pairs of pleopods. If desired artificial insemination can also be carried out with this species (Sandifer and Smith 1979). Broodstock is most often obtained by selection of "brown-egged" gravid females from production ponds. A wide variety of tank sizes and shapes have been used to maintain Macrobrachium broodstock and there exists no clear optimal size or shape. Warm water temperatures are apparently fairly critical and should be maintained at approximately 25 degrees C. A variety of both recirculating and flow through systems have been developed which are suitable for holding broodstock. Typically broodstock is maintained in bare bottomed 10 ft diameter tanks (water depth 2 ft.) at somewhat low densities with a ratio of about four females to one male. Hatchery technology - Egg-bearing females are regularly observed and as the egg mass becomes brown, the females are moved to smaller tanks for hatching. A 45 g female will typically produce 15-20,000 larvae over a 96-hour period. Larger females produce larger broods. As Macrobrachium larvae require slightly saline conditions the "brown-egged" females are usually held at a salinity of parts per thousand.

4 Page 4 Table 3. Macrobrachium hatchery technology. PRAWN (Macrobrachium) TEMP. FECUND o C 45 g female/30,000 eggs orange eggs; 19 days till hatch brown eggs; 6-12 days till hatch grey-black; 2-3 days till hatch HATCH COND Hatch Hatchery Density TEMP = 28 o C; SAL = ppt Green-water Low = larvae/liter ~ 60 % of initial # of eggs hatch (~ 20,000 larvae/45 gram female) Clear-water High = larvae/liter

5 Page 5 Culture Techniques Water hardness (the concentration of divalent cations in water) can anywhere between 20 and 200mg/L (Vasquez, et al. 1989). Principle cations in freshwater are generally calcium and magnesium although manganese and ferrous iron can also be significant. Table 4. Comparison of penaeid shrimp and Macrobrachium hatchery technology. SHRIMP PRAWN STAGE FEED H 2 O EX STAGE FEED H 2 O EX NAUPLII 0% ZOEA MYSIS PL 1 PL 10 ALGAE 10 5 /ml R 10/ml 50% R 10/ml BS 1/ml R 10/ml EBS 8/ml EBS 10-20/ml 50 ug/lar PF to II 0.5/ml BS 50% GW 100% CW IV & V 3/ml BS 75% GW 100% CW V - VIII 4/ml BS 70 ug/lar PF 80% VIII - XI 5/ml BS 150 ug/lar PF PL scouts 90% PL drop time 4.5/ml BS 200 ug/lar PF 4/ml BS 400 ug/lar PF Survival nauplii - PL 10 = 60% Survival = ~ 50% 125% GW 100% CW 150% GW 100% CW 200% GW 100% CW R = rotifers (note seldom used in commercial hatcheries); BS = brine shrimp nauplii; EBS = enriched (HUFA) brine shrimp nauplii (see Figure 1.); PF = prepared feed; GW = green water culture; CW = clear water culture.

6 Page 6 Figure 1. Highly unsaturated fatty acid (HUFA) levels in Artemia naupli enriched with Super Selco for 12 and 24 h and subsequently stored for 24 hrs at 10 o C. (adapted from Figure 7.4 New and Valenti 2000)

7 Page 7 Table 5. Composition and nutritive value of egg custard feeds for Macrobrachium rosenbergii larvae. (adapted from Table 7.3 New and Valenti 2000) Ingredients Wet weight % Chicken egg 34.0 Squid flesh 10.0 Fish flesh 10.0 Dried milk 4.0 Wheat flour 2.0 Fish liver oil 0.8 Vitamin mix 0.7 Mineral mix 0.7 Water 37.8 Total Proximate analysis Dry weight Crude protein 45.1 Crude fat 22.6 Fibre - NFE (non-fibrous extractives) 23.6 Ash 8.8 Total Gross energy (kcal/kg) 4889 Nursery Phase - In the tropics these are similar to marine shrimp. Typically, prawn nursery ponds are 0.2 ha or less in size. Stocking density in nursery ponds is generally about postlarvae/m 2 and the duration is 2-4 months. During that time prawns should grow to about g in size with better than 90% survival. Note shrimp nursery pond densities tend to be a little higher ( PLs/m 2. In temperate zones, the nursery phase is often conducted indoors where appropriate temperatures (25-28 o C) can be maintained during times (winter and early spring) when the natural temperature would inhibit growth. Densities are higher, 750-3,000 postlarvae/m 2, and growth is generally not as good ( after 2-3 months, 75% survival).

8 Page 8 Pond grow-out - Earthen ponds, somewhat smaller than shrimp ponds, averaging about a 1 hectare in size. The dikes are generally sown with vegetation to provide cover for the prawns. Growth is rapid on the average, 40 grams in 6 months, 60 grams in months (see Fig. 2), but individual variation, particularly for males, is extremely high (see Fig. 3). Growth rates are about half these in the temperate zone. Figure 2. Typical growth curve of Macrobrachium rosenbergii in a rearing pond (from Fig New and Valenti 2000) Stocking rates are 5-10/m 2 for batch harvested within 8 months. Stocking density is increased to 16-22/m 2 for those ponds being continuously harvested. Higher stocking rates (~ 20 PL s/m 2 ) tends to limit total biomass in batch harvested ponds although survival is only marginally impacted. Pond survival is generally high ~ 70% with overall production in the tropics between 500 1,000 kg/ha/year. Pond side prices are typically half that of marine shrimp.

9 Page 9 Figure 3. Length frequency distribution of male and female Macrobrachium rosenbergii showing the bimodal distribution of the bull (blue claw) and runt (orange claw) male phenomenon (from Fig New and Valenti 2000) Marketing Tail meat yield (tail shell removed) is less than penaeid shrimp. A 30-gram whole female yields 38% tail meat while the male yields 35%. Unfortunately as size increases there is a decline in yield. There is also a problem with poor quality. Both fresh and frozen Macrobrachium tails can be mushy. Short shelf-live Macrobrachium only 3 4 days for the fresh chilled ford tail meat after which it becomes mushy. Mushiness can be reduced by the use of full-strength chlorinated seawater to wash the prawns after capture. Thermal shock immersed in 50 L of water and 80 kg of ice for 30 minutes before further processing. To avoid damage to the delicate muscle structure of Macrobrachium, passing from 1 o C to - 5 o C occur as rapidly as possible (< 2 hrs.).

10 Page 10 Literature sources - AQUACOP. 1977a. Macrobrachium rosenbergii (de Man) culture in Polynesia:progress in developing a mass intensive larval rearing technique in clear water. Proceeding of the World Mariculture Society 8: Fujimura, T. and H. Okamoto Notes on progress made in developing a mass culturing technique for Macrobrachium rosenbergii in Hawaii. In: T. V. R. Pillay (editor). Coastal Aquaculture in the Indo-Pacific Region, Fishing News (Books) Ltd., London. Ling, S. W. 1969a. The general biology and development of Macrobrachium rosenbergii (de Man). FAO UN Fish. Rep. (57)3: Ling, S. W. 1969b. Methods of rearing and culturing Macrobrachium rosenbergii (de Man). FAO UN Fish. Rep. 57(3): New, M.B. and W.C. Valenti Freshwater Prawn Culture: The farming of Macrobrachium rosenbergii. Blackwell Science. 443 pp. Sandifer, P. A. and T. I. J. Smith A method for artificial insemination of Macrobrachium prawns and its potential use in inheritance and hybridization studies. Proceeding of the World Mariculture Society 10: Shang, Y. C. and T. Fujimura The production economics of freshwater prawn (Macrobrachium rosenbergii) farming in Hawaii, Aquaculture 11: