Population dynamics of Mystus albolineatus Roberts, 1994 in Southwest Vietnam

Abstract

Mystus albolineatus has a wide distribution range from freshwater to estuarine areas in the Mekong River system, including Can Tho and Soc Trang provinces in southwest Vietnam, where it plays an essential role in food resources. Recent findings, however, have shown a decreasing trend in the number of individuals caught per fishing effort. This study aimed to assess the exploitation status of this species in these provinces based on 778 fish samples collected using trawl nets with a length of 15 m, height of 3 m, and a code-end mesh of 2a = 1.5 cm from September 2022 to August 2023. Data analysis revealed that the fish population exhibited a male-to-female ratio of 0.97:1.00 and a von Bertalanffy curve of L = 15.7(1 − e-0.9(t+0.06)). The total mortality (Z) was 2.63 /year, with a natural mortality (M) of 2.05 /year and a fishing mortality (F) of 0.58 /year. The fish population remained within the acceptable exploitation limits, as the exploitation rate (Ecur = 0.22) was lower than E50 (0.386). The species population displayed a length at first capture of 9.9 cm, a maximum exploitation rate of 0.742, an optimal exploitation rate of 0.655, and a single recruitment event in May. In order to ensure sustainable exploitation of this species, fishers should avoid catching fish during its spawning season and below fish length of 9.9 cm.