Assessment of Exploited Population Dynamics of African Butter Catfish (Schilbe mystus) in Stratum VII of Lake Volta, Ghana

Abstract

The current study aimed to assess the population status of Schilbe mystus in stratum VII of Volta Lake, Ghana, based on length-frequency data collected throughout 2021. Individual fish samples, ranging from 5.5 to 22.0cm with a mean length of 11.5± 0.17cm, were analyzed using FiSAT II. The study revealed a mean condition factor of 0.36, indicating the fish's overall health. The growth pattern, estimated at 3.1 suggested positive algometric growth. The growth rate (K) was determined as 0.25 per year. Length at infinity (L∞), length at first capture (Lc50), and length at first maturity (Lm50) were calculated as 24.7, 10.27, and 16.47cm, respectively. The growth performance index was recorded at 2.58. The total mortality rate (Z) was calculated as 2.09 per year, with the natural mortality rate (M) at 0.78 per year and the fishing mortality rate (F) at 1.31 per year. The exploitation rate was 0.63, indicating overexploitation of S. mystus in Stratum VII. To sustain the stock size of the S. mystus fishery in Lake Volta, we recommend reducing fishing efforts, regular status assessments, and enforcement of fisheries regulations