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the Palau Community College (PCC) hatchery are conducting a series of experiments on improving the husbandry of mangrove crab. The information on experiments and major findings are summarized below.

1. Collection of indigenous Scylla serrata broodstock for spawning, larval rearing and growout in order to complete the life cycle of mangrove crab under domestication in Palau. It took more than one month for the wild mangrove crab broodstock (average weight of 1053g) to spawn in captivity, and about 10 days of incubation until the eggs hatched to yield 14.06 ± 4.64 million (Mean ± Std. dev., N=4) active zoeae. The zoeae then went through various larval stages, nursery stages and grew all the way to adult mangrove crabs in 13 months or so, under domestication. Among the cultured group, one berried female crab released fertilized eggs at a size of 618 grams, which contributed 5 million active Zoea I larvae. Therefore, the whole life cycle of mangrove crab was successfully closed under domestication in PCC. 2. Improvement on hatching and larval rearing performance. Black vs. Yellow Tank Color: A preliminary larval rearing trial was conducted to evaluate the effects of two different tank colors, black and yellow, on the survival rate of the mangrove crab Scylla serrata larvae using 10-ton capacity tanks. These tanks were filled with six tons of chlorine-treated seawater and were stocked with 400,000 Zoea 1 larvae. These tanks were treated with same feeding and water management schemes by following the protocol which was adopted from Kosrae Mudcrab Hatchery. The larvae were initially fed with rotifers, artificial feed (Omega Artificial Plankton B.P.) and subsequently with newly hatched artemia until they molted to megalopa stage. The larval rearing water was enriched with a combination

of Spirulina powder and micro-algae paste (Reed Mariculture Inc.) that includes Nannochloropsis sp., Tetraselmis sp., and Thallasiosira weissfolgii. These micro-algae products served as food for the rotifers and artemia nauplii that were fed daily to the crab larvae. After 15 days of larval rearing, the larvae started to molt into megalopa and this transition was completed on Day 17. A total of 376,812 mega-

lopae were harvested from the five larval rearing tanks. The highest survival rate was obtained in one of the yellow tanks which was 26.06% (104,250 megalopae) while the lowest survival rate which was 13.73% (54,991 megalopae) was in one of the black tanks. Higher survival rate was achieved in yellow tanks (23.63 ± 0.03%) than in black tanks (15.66 ± 0.02%).

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AQUACULTURE MAGAZINE December 2018 January 2019_VOL 44 NUM 6  

Production of omega-3 enriched tilapia through the dietary use of algae meal or fish oil: improved nutrient value of fillet and offal

AQUACULTURE MAGAZINE December 2018 January 2019_VOL 44 NUM 6  

Production of omega-3 enriched tilapia through the dietary use of algae meal or fish oil: improved nutrient value of fillet and offal