Catch and Length-weight relationships of Silky shark (Carcharhinus falciformis)
Prayudi Budi Utomo1, Arief Reza Fahlevi2, Dian Novianto3, Muhammad Taufik3, Umi Chodrijah3

1 Directorate General of Marine and Fisheries Product Competitivenes, Ministry of Marine Affairs and Fisheries

2 Coastal and Marine Resource Management Unit of Sorong, Directorate General of Management of Marine Spatial Planning, Ministry of Marine Affairs and Fisheries

3 Research Center for Fishery, National Research and Innovation Agency


E-mail: dian.novianto[at]brin.go.id

Abstract

Shark fishing is a kind of fishery that is quite beneficial on Biak Island. The significant market demand for shark fishery goods implies that fishermen are still actively catching sharks as fishing targets. We present length-weight (LWR) relationships of the silky shark (n=128) caught by the commercial drift longline in the Biak Island part of South West Pacific between February to September 2021 and describe the supply chains of sharks in this fisheries. The type of longline employed is a surface longline with bullet tuna, skipjack tuna, yellowfin tuna and shark meat as bait with a maximum catch rate of 39 individuals and an average catch of 13 per setting, dominated by silky sharks. The total length ranged of silky shark between 140 - 234 cm for males and 173-225 cm for females, were predominantly caught at lengths between 196 and 210 cm TL. Furthermore, the relationships of length-weight relationships were significant with the coefficient of determination (r2) of around 0.74 with allometric positive growth patterns. A system of predetermined quotas governs the marketing of shark fisheries products. While shark meat is normally processed into salted fish that is traded in the Biak island and some of which is sold out from island, shark fins are typically dried and then exported.
Keywords : Silky shark, length-weight relationships, drift longline

Keywords: Silky shark, length-weight relationships, drift longline

Topic: Sustainable Aquaculture and Fisheries