Diversity of non-targeted species on blue swimming crab Portunus pelagicus gillnet fishery in Grogol, Cirebon

Non-targeted Species (NTS) data and research is needed in the management and development of the blue swimming crab fishery ecosystem. The NTS were divided into two groups, namely the retained and the discarded. This study aims to explain the diversity of NTS caught by blue swimming crab fishermen that used gillnet in the Cirebon Regency. This study uses exploration and enumeration methods to analyze the catch of NTS catched by blue swimming crab fishermen for 7 months in 2021. Shannon-Wiener diversity, Evenness, and Simpson's dominance index were further analyzed. Results showed the diversity of NTS caught by blue swimming crab fishermen with gillnets in Cirebon Regency consisted of 29 species from 23 families (9 fish, 16 crustaceans, and 4 mollusc species). The highest diversity index was observed in December (2.16) and the lowest was October (1.29). The highest population uniformity or evenness was observed in September (0.83) and the lowest in October and November (0.59). The dominance index had the highest value in August at 0.41 and the lowest in July at 0.15. The non-target species biodiversity of P. pelagicus fishery in Cirebon was classified as moderate diversity category, moderate to high evenness, and low dominance. These results provide information for fishermen to reduce catches of non-targeted species which requires fishermen to return and release the non-targeted species within 5 minutes and maintain the diversity of marine biota.