Reproduction Study of Lemuru(Sardinella lemuru Blk.) Based on Sexual Maturity and Fish Length to Predict Spawning Season at East Coast of Siberut Island

Abstract

The aim of this research is to evaluate reproductive pattern of Sardine (Sardinella lemuru Blk.) in east coast of Siberut Island. The study was focused on observation of reproductive attributes including sexual maturity, fecundity, body length and body weight by collecting =50 samples monthly for one year. A total sampel of 777 fish were caught using gillnet and measured individually before dissecting to analyze sex and gonadal maturity. Gonadal Somatic Index (GSI) and egg diameter were analyzed according Gaughan et al. (2000) to determine body size at first maturity and spawning season that will be useful as important consideration for management policy of Sardinella in Siberut Island. Based on the relationship between sexual maturity and body size, Sardinella lemuru begin to spawn at 163 mm and 153 mm in length for female and male respectively. Female Lemuru can produce 1.688 – 21.573 egg for each spawning time with average fecundity 7.850 egg. Sexual maturity status that recorded for one year indicated that spawning season take place between September and October. There is no evidence that lemuru spawn more than one time a year and distribution of egg diameter showed that Sardinella lemuru is partial spawner that spawn more than one time during spawning season.