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

Abstract

This 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.

Changes in some biological parameters of the silver cyprinid, Rastrineobola argentea (Pellegrin, 1904) in the Nyanza Gulf of Lake Victoria, Kenya

“…The fecundity of R. argentea is believed to increase with increased fish size (Cowx, Rollins, & Tumwebaze, ), with the increased fecundity of R. argentea possibly being a strategy to maximize reproductive success in response to overexploitation of the fish stocks in Lake Victoria. R. argentea now grows faster, attaining maturity more rapidly (Yongo, Manyala, & Agembe, ). Several earlier studies reported size at maturity for R. argentea in Lake Victoria from 1973 to the present study, as presented in Table .…”

Trends in an emerging artisanal fishery of the African cyprinid Rastrineobola argentea in Lake Nabugabo, Uganda

“…The R. argentea fish stock is now the most important by mass in Lake Victoria, with landings of more than 65,000 t annually, although this number is believed to be higher (Katunzi et al, 2017;NaFIRRI, 2016;Njiru et al, 2014;Rudd & Branch, 2017;Sharpe et al, 2012). The R. argentea fishery is an important source of revenue for low-income rural populations and particularly for women, who play important roles in post-harvest processing activities such as drying and selling fish, and is a major contributor to both local and regional food security (Katunzi et al, 2017;Kolding et al, 2019;Sharpe et al, 2012;Yongo et al, 2018).…”