The frequency distribution of the length, gonad maturity stages, sex ratio, length at first mature and catch, width-weight relationship, and fisheries factors of blue swimmer crab (Portunus pelagicus) caught by crab nets landed at Tegalsari coastal fisheries port in Central Java

Abstract

The research of biology and fisheries aspects of blue swimmer crab (Portunus pelagicus) caught by arad trawl was done at Tegalsari Coastal Fishing Port in Central Java. Data were collected from 755 individuals. The research method was survey, descriptive analysis and interviews. The most frequently catch fish was between 115.9 – 127.7 mm. They was positive allometric pattern. Width weight relationship had equation (all samples) W=0.0000311 L3.1623 and (males) W = 0.0000249 L3.2202 and (females) W = 0.0000536 L3.0378. Lenght at first maturity was 124.74 mm (male) and 113.57 mm (females). The Lm value of all samples was 110.17 mm, and the Lc value was 120.4 mm, it means Lc> Lm, the catch crabs still had a chance to mature and spawn. Investigation, however, on fisheries aspects become important in this case. The present study provides a basic and valuable information for the crab fisheries management and population monitoring.