Growth, mortality and exploitation rate of Plectropomus maculatus and P. oligocanthus (Groupers, Serranidae) on Cenderawasih Bay National Park, Indonesia

Abstract

The present study aims to determine whether the rate of exploitation for grouper stocks is in accordance with their biological attributes (growth and mortality). The results showed that Plectropomus maculatus and P. oligocanthus taken from Cenderawasih Bay National Park (CBNP) were in the size category of actively productive spawning phase. P. maculatus could reach a maximum length (L1) of 484.05 mm and growth rate (K) of 0.34 per year. P. oligocanthus was capable of reaching L1 of 481.95 mm and K of 0.66 per year. Estimation of total mortality (Z) for P. maculatus was 0.988 and P Oligocanthus was 2.056. In addition, fishing mortality (F) for P. maculatus and P. oligocanthus were 0.564 and 0.399 respectively. Based on the estimated mortality values, it was estimated that the exploitation rate (E) of P. maculatus was 0.570, and P. oligocanthus was 0.681. Management settings for P. maculatus and P. oligocanthus can be separately based on the species so that the fishing can be sustainable. The introduction of minimum size limits for fish caught can be applied as a protection from hook and hand line fishing activities in CBNP.