Exploring the vulnerability of a commonly exploited fish stock, Galeoides decadactylus in the artisanal mixed capture fisheries of Sierra Leone

Abstract

Galeoides decadactylus is a commonly exploited fish stock in Sierra Leone, and the study of its vulnerability to capture in the artisanal mixed fisheries of Sierra Leone has not gained the needed attention of researchers, for which the present study has come in handy particularly when such information is critical for sustainable management of the stock. The study utilized length-frequency data obtained from 865 specimens as input datasets of analytical models inscribed for the FAO Fish Stock Assessment Tool (FiSAT II) software. Vulnerability indices for this study were the Length Structured Virtual Population Analysis (LVPA) and the Probability of Capture (PC). Results revealed minimum and maximum total length of 11cm and 36cm respectively for the study species, and LVPA showed highest catch (in numbers) for the length range, 20 cm (n = 94, 0000) - 21 cm (n = 100, 000). Also, the probability of capture evinced greater selection probability (p = 0.9) of the larger sizes (17cm - 22 cm (mean, 19.5 cm TL) at a maximum mesh size of 8cm of bottom drift net utilised by the fishers. The results of LVPA implied that the smaller length groups of the assessed stock (TL  are less vulnerable to fishing mortality, but most susceptible to natural mortality, and the probability of capture indicated that the gill nets used by the artisanal fishers for this study were highly selective to allow greater number (n = 4.8 x 10⁶) of the smaller length group escape capture. In conclusion, G. decadactylus was efficiently exploited in the artisanal mixed fisheries. However, stringent measures on capture input and output controls are advised for the assessed stock.