The Indian mackerel (Rastrelliger kanagurta) is a commercially important fish species in Bangladesh. This study was conducted by using two catch-based methods, Depletion-Based Stock Reduction Analysis (DB-SRA) and Catch-Maximum Sustainable Yield (CMSY), to determine stock status with length-based approaches to update the life-history estimates of Indian mackerel stock. Sensitivity tests and projection were also performed to find out how well the models predicted the estimates at different input parameter's value and evaluate catch strategies. The life-history parameters were estimated as L∞=33.25 cm and k = 0.92 year- 1. The fishery experienced a sudden increase in its landings to the abnormally highest point in 2012, followed by a state of equilibrium. However, the current spawning potential ratio (SPR) of 17% indicated a concerning sign regarding stock spawning capacity, where over 50% of catches were observed to be below the maturity level. This study suggests an optimum length limit of 18-22 cm to adjust the growth and recruitment overfishing. Hence, an annual catch limit of 1500 mt is recommended for the next 15 years under the maximum sustainable yield (MSY) reference bar (1967 mt), in convergence with the annual fishing ban, to gradually maintain the current overfished biomass of Indian mackerel approaching the BMSY level. Besides, the dynamic, transboundary nature of the Indian mackerel demands both national action and international cooperation for better management.
Barua et al. (Tue,) studied this question.