A rapid fishery assessment to collect biological information and life-history parameters for rednose labeo Labeo rosae and Mozambique tilapia Oreochromis mossambicus in Loskop Dam, Olifants River, South Africa

Abstract

A 2-week rapid fishery assessment using various sampling gears was conducted to collect life-history data on rednose labeo Labeo rosae  and Mozambique tilapia Oreochromis mossambicus in Loskop Dam on the Olifants River, Mpumalanga Province, South Africa. These  native species were the two most-abundant fish species caught in the impoundment during the study. Both species displayed a bimodal  population size distribution comprised of recent recruits and large-sized individuals. Isometric growth (b value ~3), an asymptotic length  (L∞) of 447 mm, and length at 50% sexual maturity (Lm50) of 198 mm were estimated for L. rosae. Isometric growth, L∞ of 451 mm, and  Lm50 of 124 mm were estimated for O. mossambicus. This rapid assessment at Loskop Dam produced sets of life-history parameters   comparable to those previously reported for these two species in Flag Boshielo Dam, ~80 km downstream.