Domestication of black tiger shrimp (Penaeus monodon) in recirculation systems in Vietnam

Black tiger shrimp Penaeus monodon is the most valuable species for commercial aquaculture in Vietnam. Annual shrimp production has contributed 40-43% of the fisheries export turnover of the country. However, the total relyance on wild resources for breeders makes the farming industry of P. monodon unsustainable. Using wild broodstock has resulted in several challenges such as vertical disease transmission from the broodstock to the offspring, declining natural resources due to overfishing of wild broodstocks, etc. Therefore, the development of successful domestication techniques to produce specific pathogen free (SPF) P. monodon broodstocks is urgently needed for sustainable development of P. monodon aquaculture. The current study aims to develop techniques to close the life cycle of P. monodon in captivity, including (i) develop an indoor rearing system for domestication of P. monodon (ii) develop a protocol for the different rearing phases of P. monodon from eggs to breeders (iii) develop a fresh-food maturation diet and a maturation feeding regime for improving egg fecundity and egg hatching success of captive P. monodon broodstocks (iv) evaluation of the spawning performance and offspring quality of domesticated P. monodon stock, and (v) evaluation of the grow-out performance of domesticated P. monodon stock. Several system designs and trials at the start of the study eventually led to the development of a sandbased recirculation system that has offered a unique set-up for further experiments on domestication as well as on P. monodon reproduction. A sand-based recirculation system with low water exchange at 5-10% a day and a combination diet of fresh-food mixture and high protein pellets resulted in high survival and good growth. Low salinity (20-23g.L-1) and low stocking density (10 animals per m2) produced the best growth and survival during the grow-out phase of P. monodon. A fresh-food maturation diet formulated to resemble the ratios of highly unsaturated fatty acids of mature ovaries of wild P. monodon significantly improved growth and fecundity of the P. monodon broodstocks. A maturation feeding regime of 40 % fresh-food mixture and 60% semi-moist maturation pellets significantly improved hatching success and offspring quality. Grow-out trials at different intensive farms indicated domesticated P. monodon stock performs better in terms of growth and harvest yield than non-domesticated stock. This thesis, for the first time, has documented a protocol for indoor domestication of P. monodon in Vietnam, successfully closing the life cycle from egg to breeders which are capable to produce viable offspring through several generations. Further studies on genetic improvement and selective breeding could give a tremendous boost to the local shrimp farming industry in the coming years