Growth, mortality and recruitment of silver cyprinid (Rastrineobola argentea) in the open waters of Lake Victoria, Kenya

Abstract

AbstractThis study investigated the growth, mortality and recruitment of Rastrineobola argentea in Lake Victoria on the basis of length–frequency data collected during the period 2014–2015. The asymptotic length (L∞) had a mean (±SE) value of 53.50 ± 0.50 mm SL, growth curvature (K) of 0.81 ± 0.06 year−1, total mortality (Z) of 2.96 ± 0.12 year−1, a natural mortality (M) of 1.23 ± 0.06 year−1, a fishing mortality (F) of 1.74 ± 0.07 year−1, an exploitation rate (E) of 0.59 ± 0.01, a growth performance index (∅′) of 3.36 ± 0.02 and a length at 50% capture (L50) of 28.25 ± 0.43 mm SL. The fish exhibited a peak breeding during the months of May and August. The Beverton and Holt relative yield‐per‐recruit model indicated mean (±SE) indices as 0.37 ± 0.01 for optimum sustainable yield (E0.5), 0.76 ± 0.01 for maximum sustainable yield (Emax) and 0.66 ± 0.01 for economic yield (E0.1). Compared with previous studies, there is a great decline in the sizes of R. argentea stocks in Lake Victoria. Thus, management measures should include restriction on illegal seine nets <10 mm mesh size and re‐enforcement of a fishing ban or a closed season.