POSSIBLE USE OF A STOCK–PRODUCTION MODEL INCORPORATING COVARIATES (ASPIC) FOR STOCK ASSESSMENT OF RAYS IN THE INDIAN OCEAN OF INDONESIA

Abstract

Limited-data sheets, in general, arestill major challenges in managing shark and ray. An analytical model, such as age-structured models has been developed recently to estimate population status of fisheries. However, this model must require sufficient data especially for tropical fisheries, as it is difficult to measure age of many fishes and often impractical in these fisheries. Catch-effort data arearguing to be the affordable and best available in tropical-based fisheries including Indonesia’s fisheries. This research aims to examine the potential application of A Stock-Production Model Incorporating Covariates (ASPIC) to investigate stock statusof ray in the Indian Ocean(FMA 571, 572 and 573) based on catch-effort data in 2005-2015. The results showed that the stock status became to be pessimistic because of substantial increase in catches in recent years. The results from most of scenarios indicate the current status of rays in Indian Ocean may be overfishing and overfished (B2016 /Bmsy=0.304; F2015 /Fmsy=1.45). An effort reduction urgently required to ensure the long-term benefits of ray population about 45% of an effort in 2015 (24,506 unit that equal to gillnet).ASPIC is potentially used to examine the status of ray, however, improvement on data collection must be crucially needed to provide appropriate stock analysis.