Assessment approach of production models to commercial pelagic catch and effort data of Indian mackerel (Rastrelliger kanagurta, Cuvier, 1816) in the Arabian Sea

Abstract

Globally, Reference Points (RPs) indicators are usually lifted in the science of fisheries management for the alternative running objectives and tracking the condition of fisheries. The Fox Model (FM) and Logistic Model (LM) in A Stock Production Model Incorporates Covariates (ASPIC) estimated F = 0.062 – 0.132 and F = 0.059 – 0.126 from 2003 to 2018 with F/F_MSY showing an increased inclination from 0.628 to 1.346 and 1.027 to 2.179, respectively. Estimated Starting Biomass (B) = 520800 – 263100 MT and B = 541000 – 277000 MT from population trajectory (Non-bootstrapped) sharply decreased to the ratio of biomass to B_MSY (B/B_MSY) 2.810 – 1.420 and 2.075 – 1.063, respectively. Furthermore, the uncertainties reported in Maximum Sustainable Yield (MSY) (18210 – 15050 MT), F_MSY (0.098 – 0.058) and B_MSY (185300 – 260700 MT) from FM and LM was also estimated in ASPIC using 0.8 Initial Proportion (IP) of starting Maximum Catch (MC) that was 80 %. According to Target Reference Points (TRPs), CEDA and ASPIC (11000 – 18000 MT and 15000 – 18000 MT) range also indicate overexploitation of the Indian mackerel in the Arabian Sea of Pakistan. Estimated Predicted Yield (PY) of 28841 MT in 2003 and even Recent Catch (RC) of 19421 MT in 2018 is far away from harvested yield values of 31126 and 33658 MT and even MC of 38504 MT, pinpointing this research in a questionable and overexploitation state. Ideally, Fishing Effort (FE) should be reduced at the level of PY which is approximately 12000 fishing vessels (19421 MT) against the current engaged FE of about 19000 fishing vessels (33658 MT) in 2018 for the Indian mackerel fishery in Pakistan. In order to prevent this huge economic loss and to reduce the efforts of fisheries, it is suggested that strict and immediate measures should be followed by the policy makers and law enforcement organizations against the mesh size and illegal nets for this type of commercially important fishery.