BIOLOGI REPRODUKSI IKAN BELANAK (Planiliza subviridis) DI PERAIRAN PANTAI CILINCING, TELUK JAKARTA

Abstract

Anthropogenic activities trigger water pollution on the coast of Jakarta Bay, which can threaten the existence of mullet (Planiliza subviridis) stocks. This research aims to examine the reproductive biology of the fish in the Cilincing coastal waters. Sampling was carried out for 6 months (February-July 2023) in the waters using a gill net with a mesh size of 0,5-1,5 inches. The total samples of the fish collected were 204 individuals (123 males and 81 females), with a total length distribution of 15.50-26.25 mm. The results show that sex ratio (M/F) of the fish was 1.5:1. Based on the gonad maturity stages, quite a lot of fish were found in the mature and spent conditions in June-July. The highest mean values of the gonad maturity index (GSI) of the fish were in May and July (male), and April and July (female). The gonad maturity index of the female mullet was higher than the male one. The size of the first mature gonads of the fish were 163-175 mm (males), and 150-162 mm (females). The spawning season occurs in July with quite high reproductive potential. The fecundity of the fish ranged from 267,333 to 956,676 oocytes. Based on the distribution of the oocytes, mullets are thought to have a total spawner type of spawning.