Evaluation of Individual Rearing of a Genetically Improved Giant River Prawn Macrobrachium rosenbergii Broodstock as an Alternate Approach to Group Rearing During the Post-Selection Rearing Phase

CIFA-GI Scampi® is a genetically improved, fast-growing strain of giant river prawn (Macrobrachium rosenbergii) developed by ICAR-Central Institute of Freshwater Aquaculture. Each year, selected broodstock are reared family-wise in nylon hapas for 3–4 months before use as parents for the next generation. However, this group rearing phase (GR) results in loss of quality broodstock due to aggression and cannibalism. This study evaluated individual rearing (IR) as an alternative to group rearing (GR). GR involved rearing of males or females in separate hapas, while IR placed males and females in separate hard plastic mesh boxes in ponds (18 boxes each). Results showed significantly higher average daily weight gain in GR, but IR achieved 100% survival for both sexes, compared to 50% (males) and 77.8% (females) in GR. No significant differences were observed in female maturity or male morphotypes (small male and no claw morphotypes). Given the markedly higher survival in IR, it is a viable alternative for post-selection rearing to minimize loss of valuable broodstock in the selective breeding program.