Estimating the catchable size of orange-spotted grouper (Epinephelus coioides) in Kwandang Bay, Gorontalo Utara District, Indonesia

Abstract

The orange-spotted grouper (Epinephelus coioides) is a valuable food fish. To support the sustainable management of orange-spotted grouper fisheries, it is important to determine the optimum catchable size. The purpose of this study was to determine an optimal catchable size for the orange-spotted grouper stock in Kwandang Bay, North Gorontalo District, Indonesia. The Catchable size was determined based on the size at first sexual maturity, fecundity, and reproductive potential. The study was conducted from December 2016 to November 2017. The size at first sexual maturity was estimated based on the examination of gonads from 141 specimens, while fecundity was estimated based on a sample of 40 female fish with ripe gonads. The mean total length (TL) at first maturity was 40 cm. Fecundity ranged from 30,526 - 1,395,846 eggs with a mean of 687,025 eggs. The reproductive potential was highest in the size range of 55-64 cm TL. The recommended size for orange-spotted grouper is above 64 cm, to enable females to attain their maximum level of egg production before capture and thus contribute to maintaining the stock.