Yield-per-recruit modeling as biological reference points to provide fisheries management of Leopard Coral Grouper (Plectropomus leopardus) in Saleh Bay, West Nusa Tenggara

Abstract

Leopard coral grouper (Plectropomus leopardus) is an important fisheries commodity in Saleh Bay, both ecologically and economically. Continuous exploitation of this species has caused population collapses in some waters due to high fishing pressure. Therefore, it is very important to estimate its population stock. Yield per recruit models usually being used to evaluate population stock also to estimate biological reference point. We estimated life-history parameters using length-based stock assessment, while stock size was estimated by virtual population analysis (VPA), and finally, prediction models was estimated using Beverton & Holt’s yield per recruit model. We used the following variables: growth parameters, fishing mortality, length at first capture, and age at 50% recruitment into the fishery. From these variables we found that the Fcurrent (0.26) is higher than the target reference point (FMSY= 0.24), which confirmed the indication of slight increased exploitation rate (E=0.62). It is shown that the Plectropomus leopardus was overexploited with spawner biomass-per-recruit at 20.6% of pristine levels. The regulation measures to correct the exploitation pattern and to reduce fishing mortality smaller than Fmsy including limiting the catch size and control on fishing gear by limiting fishing effort.