Sustainability Status of the Fishery for Cephalopholis sonnerati (Tomato Hind) in Sri Lankan Waters: A Length-Based Assessment of Survival and Management Needs

Cephalopholis sonnerati, a grouper species, is a primary target of the export market in Sri Lanka. Significant harvesting occurred between 2015 and 2017, driven by the Live Reef Food Fish Trade in addition to small-scale coastal fisheries. Nevertheless, no scientific studies have assessed the sustainability of the fishery or the status of C. sonnerati populations in Sri Lankan waters. To address this gap, we utilized length-based, data-limited approaches to assess the sustainability of the fishery for C. sonnerati in eastern and western coastal waters in Sri Lanka. The von Bertalanffy growth parameters were separately estimated for the western and eastern populations: L_∞ = 63.1 and 62.4 cm (TL); K = 0.26 and 0.24/year; mean M = 0.50 and 0.47/year; and L₅₀ = 36.0 and 43.5 cm (TL). Length-based indicators (LBIs) and F_max suggest that the fishery for C. sonnerati was operating at MSY levels. However, LBIs for the conservation of immature and mature individuals for both populations fell below the expected levels, indicating fishery unsustainability. The length-based spawning potential ratios (LBSPRs) of the western and eastern coastal populations were estimated to be 24% and 13%, respectively, below the expected reference points of the LBSPR. Furthermore, the models showed size selectivity estimates at 50% and 95% were lower than the estimated sizes at L₅₀. In conclusion, it is suggested that C. sonnerati populations in western and eastern coastal waters are presumably at risk of overexploitation by growth and recruitment overfishing, highlighting the need for effective management and conservation plans.