Biological Aspect Analysis of Indian Mackerel (Rastrelliger kanagurta Cuvier, 1816) Caught by Purse Seine in Probolinggo Waters, Madura Strait, East Java

Abstract

Indian mackerel (Rastrelliger kanagurta) is one of pelagic fish caught in Probolinggo waters using purse seine. This research was conducted from January until May, 2017 at Paiton Fishing Port, Probolinggo. The purpose of this research was to identify biological aspects of Indian mackerel namely sex ratio, gonad maturity level (GML), gonado somatic index (GSI), length-weight relationship, length at first mature (Lm), length at first capture (Lc), and growth parameters such as L∞, K, and t0. The research was using direct method survey. Fish samples were taken directly from fishing vessels landed their catch in Paiton Fishing Port, Probolinggo. Result showed that sex ratio female and male was 1 : 1.19 with proportion of female and male 44.63% and 54.38% respectively. Gonad maturity level (GML) was dominated by immature fish (91.3%). Gonado Somatic Index (GSI) ranged from 0.0079 to 0.679. The formula of length and weight relationship was W=0.0007275.L3.15 with the growth type of positive allometric. Length at first mature (Lm) of male and female was 22.9 cm and 22.5 cm respectively. In addition, Length at first capture (Lc) of Indian mackerel was 17.02 cm. Growth parameters of fish were L∞ = 23.40 cm, K = 1.03 per year, and t0 = -0.165 year. Based on GML and Lc values, it can be concluded that the Indian mackerel resource in Probolinggo waters was mostly caught before mature.