Population dynamics of thresher shark (Alopias pelagicus) landed at the Kutaraja fishing port, Banda Aceh

Abstract

At the Kutaraja Fishing Port, the shark species Alopias pelagicus accounts for the vast majority of shark catches. The purpose of this research was to ascertain the length distribution of A. pelagicus, the length at which it was first captured, the sex ratio, the von Bertalanffy growth parameters and functions, the mortality rate, and the exploitation rate. This study was carried out in the Kutaraja Fishing Port from December 2021 to February 2022. The incidental sampling method was used to collect 406 samples in total. The FAO-ICLARM Stock Assessment Tools were utilized to analyze population dynamics parameters. The male, female, and combined length distributions of A. pelagicus ranged from 186-295cmTL, 205-304cmTL, and 186-305cmTL, respectively. The length of the first capture was 249.40 cmTL, 252.29 cmTL and 250.78 cmTL, sex ratio of males and females is 1:2.24, the asymptotic length (L∞) was 344.25 cmTL, fish age at length 0 (t0) was 0.066/year, with a growth rate (k) of 0.50/year, 0.36/year dan 0.19/year, 374.83 cmTL and 378.92 cmTL, 0.058/year dan 0.048/year. Natural mortality (M) was assessed to be 0.59/year, 0.47/year, and 0.31/year, fishing mortality (F) was 2.08/year, 2.47/year, and 2.20/year, and total mortality (Z) was 2.67/year, 2.94/year, and 2.51/year. The A. pelagicus exploitation rate (E) was 0.78/year, 0.84/year, and 0.88/year, demonstrating complete exploitation of the male, female, and combined populations.