White sardine (Escualosa thoracata) stock status in coastal waters of Bangladesh

Abstract

The marine fisheries of Bangladesh have experienced an uncontrolled expansion of fishing over the last few decades. Consequently, most fish stocks became vulnerable to overfishing. Similar to many other fisheries, catch of white sardine (Escualosa thoracata) is rapidly declining. Therefore, three data-limited approaches (length-based Bayesian biomass analysis, LBB; length-based spawning potential ratio, LB-SPR; and Froese's length-based indicators, LBIs) were used to estimate growth, mortality, and fisheries reference points to evaluate stock status of the white sardine fishery. Results revealed that the fishery is being overfished: F/M = 1.32 years⁻¹ in LBB and 6.67 years⁻¹ in LB-SPR. However, the stock biomass is still good with B/B₀ = 0.43 and B/B_MSY = 1.20. Stock indicators revealed that the fishery was mainly targeting mature fishes, most of which were mega-spawners (older, larger fish), which suggested stocks were recruitment overfished. Harvesting an optimum size range (6.57 to 8.03 cm) and reducing fishing mortality to a sustainable level (F = M) would sustain a healthy stock biomass.