Shrimp and mud crab domestication program The program continued to address the problem of declining supply of good quality broodstock and seed of indigenous crustacean species particularly the tiger shrimp Penaeus monodon and white shrimp P. indicus and the mud crab Scylla species. The approach was improvement of husbandry techniques in all phases of culture: broodstock management, larval rearing, nursery, grow-out and fattening. For shrimps, studies in 2011 further refined methods in domestication; and for mud crab, studies focused on improving survival and quality of produce from the hatchery, nursery and grow-out. These studies and activities were also linked to the regional program on sustainable aquaculture under the ASEANSEAFDEC Fisheries Consultative Group.
In a collaborative study with UPV funded by *DOST-PCAARRD, P. monodon broodstock from Luzon, Visayas and Mindanao were collected for genetic characterization using microsatellite DNA analysis. Statistcal analysis showed that there was no significant difference in the genetic variability among populations from Zambales, Himamaylan (Negros), Casanayan (Roxas), Mabini (Bohol), Puerto Princesa (Palawan), Masbate, Digos (Davao), Butuan, Hinatuan, and Ozamis. Pairwise FST estimates among the populations showed that the shortest genetic distance is between stocks from Ozamis and Casanayan (distance=-0.001) and the greatest distance is between stocks from Zambales and Butuan (distance = 0.047). P. indicus F1 adults that had been reared completely in captivity were stocked with those from other families so that reciprocal matings can occur. At least seven mass pairings involving five families were done to produce F2. Twenty batches of F2 have been produced from reciprocal matings. About 30% of the spawnings did not result in nauplii production because eggs were unfertilized, although the
thelyca were opaque white, indicating that the spawners were mated. Hatching rates greatly varied and ranged from 23 to 92%. Several rematurations were observed, but the number of eggs and nauplii, and hatching rates did not show increasing or decreasing trends with rematuration. During the period when temperatures reached 34oC, larval survival was very low and no maturation was observed.
PHOTOS by FD ESTEPA
Biosecure ponds (plastic-lined) where tiger shrimp postlarvae are stocked (left); larval tanks for rearing different families of white shrimp
Shrimp
* DOST-PCAARRD: Department of Science & Technology Philippine Council for Agriculture, Aquatic & Natural Resources Research & Development
SEAFDEC Aquaculture Department
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