POPULATION DYNAMIC OF SPOTTED SCAT (SCATOPHAGUS ARGUS LINN) IN SEMARANG BAY WATERS OF SEMARANG, CENTRAL JAVA

Abstract

The Spotted Scat (Scatophagus argus) is found the coastal waters of the Indo-West Pacific, from southern India and Sri Lanka to southern Japan and north to southeastern Australia and Philippines. Spotted Scat can tolerate various salinities, so they can live in coastal waters, bays, estuaries, and river waters. The study was conducted to assess the population dynamics of Spotted Scat in the waters of Semarang Bay, Central Java. The research used survey method. Fish samples was taken from 3 (three) PPIs, namely PPI Tanggulmalang and Bandengan in Kendal Regency, and PPI Tambaklorok Semarang City. The research was conducted from April to August 2021. The results showed that the Spotted Scat caught during the study had a total length from 82 – 165 mm. The total length mode was127-136 mm. The first length capture (Lc) of 106 mm. The peak of recruitment on July. The equation of relationship between length and weight of Spotted Scat was W = 0.002* L2.58, with a negative allometric growth pattern. The equation von Bertalanffy of Spotted Scat followed Lt = 178 [1-exp-0.73(t-0.06)]. The total mortality rate (Z) was 1.96, fishing mortality (F) 1.06-1 and natural mortality (M) 0.90. The exploitation rate (E) was 0.54, has been above the optimum (E = 0.5).