Determining the population dynamics of Istiophorus albicans (Latreille, 1804) in coastal waters of the Gulf of Guinea using length frequency data

Abstract

Atlantic sailfish catches in Ghana have declined to levels below historical levels, despite their economic and nutritional significance, raising concerns about a potential collapse of the fishery. This preliminary study aimed to assess the exploitation status of Atlantic sailfish (Istiophorus albicans) from the coast of Ghana, utilising FiSAT II software. Of the length distribution of 713 specimens sampled from Dixcove and Tema fishing communities, asymptotic length (L∞), growth rate (K), and age at length zero (t0) were 325.5 cm, 0.59 yr−1, and - 0.13, respectively. Total mortality rate (Z), natural mortality rate (M), and fishing mortality rate (F) were 3.05 yr−1, 0.44 yr−1, and 2.61 yr−1, respectively. The length at capture (Lc50 = 186.15 cm) exceeded the length at maturity (Lm50 = 150.6 cm). The current exploitation rate (E = 0.86) exceeded the maximum sustainable exploitation rate (E < Emax), indicating a potential collapse of the fishery without effective management measures. Based on the findings, there is an urgent need to implement effective management strategies to sustain the Atlantic sailfish population along Ghana's coast.