Immature individuals dominate elasmobranch fisheries of the Bali Strait

Abstract

Elasmobranchs play an important role in the functioning of marine ecosystems and top-down control in food webs. However, overexploitation threatens elasmobranch populations worldwide. Indonesia is currently the leading elasmobranch fishing nation, yet elasmobranch management in Indonesia is challenging because of the paucity of data on elasmobranch fisheries, especially at a species level. This study examined the elasmobranch fisheries of the Bali Strait by describing the species, sex and size composition of the elasmobranch catch landed at a major port in Eastern Java, Indonesia. Data were collected between August 2017 and March 2018 in Muncar. Elasmobranchs were identified to species level and sexed. The disc width and length of 301 rays and the precaudal length and fork length of 1657 sharks were measured. In all, 53 species were identified, many of which are at conservation risk, including species with national and international protection. Vulnerability to fishing gear varied across sex and size of each species, with immature individuals dominating the catch of most species. The findings emphasise the need for improved management of elasmobranchs in Indonesia and could help identify priorities or form strategies. Additional regional and fisheries-specific research is recommended to develop efficient and locally adapted management strategies.