Seasonal comparison of catch abundance and size of blue swimming crab ( Portunus pelagicus) in Rembang, Central Java

Abstract

Considering the blue swimming crab (Portunus pelagicus) was exported as pasteurized crab meat, the quality of fresh meat (stock and size) could have been influenced by the season and needed to be considered. This study aimed to analyse the effect of the season on the crab's abundance and size in Rembang Water, Central Java. The study period includes four seasons, namely west monsoon, first transition, east monsoon, and second transition from July 2021 to June 2022. The crab samples from the fishermen were analysed in term of the fishing trips, weight, and carapace width at the fishing ground location. Descriptive statistics and univariate one-way ANOVA was used to analyze the data. The average abundance, weight, and size of crabs caught in Rembang waters during the year were 1,8 kilograms per trip a day (one-day fishing). The abundance of crabs in the west monsoons was greater than in the east monsoons. The pattern of crabs caught was higher at the beginning of the west monsoon (December-January), then it decreased in February until the start of the first transition (March), then gradually increased in April before decreasing again in June until the end of the second transition (October). The ANOVA test showed that the size of crabs in every season had significant differences. It was clearly shown on the boxplot that the catch in the west monsoon and the first transition was smaller than the east monsoon and second transition. These results can provide insightful information for fishers, managers, and policy makers as a basis for developing sustainable fisheries management.