Reproductive biology,growth and mortality of the introduced red claw crayfish,cherax quadricarinatus in Kafue floodplain fishery

Abstract

A study of the reproductive biology, growth and mortality of the introduced red claw crayfish, Cherax quadricarinatus species in the Kafue floodplains was undertaken from September to November 2015. Samples of red claw crayfish were collected from three different stations / parts of the floodplains: station I, Kafue Road Bridge; station II, Namalyo in Monze; and station III, Kakuzu in Namwala. The parameters measured and recorded included carapace length (CL), total length (TL) and body weight (BW) from each specimen in the sample. Breeding seasonality of the crustacean was assessed using length frequency histograms from data compiled from the samples collected. Analysis and comparison of growth and determination of growth performance indexes of the red claw crayfish in different parts of the Kafue floodplains were done through one-way analysis of variance (ANOVA) and growth curves, and empirical equation by Pauly and Munro (1984), respectively. The Von Bertalanffy growth parameters L∞ and k were determined using Pauly’s equation of 1979 and Ford-Walford (1946) method. Mortality rates were computed using mean length method of Beverton and Holt equation of 1952 and Pauly’s equation of 1980. Length frequency histograms constructed showed distinct peaks indicating that the species has well-defined spawning seasons. Further, the investigation observed that there were no significant differences in growth and growth performance indices of red claw crayfish in different parts of the Kafue Floodplain fishery. Mortalities are due to natural causes and fishing.