Reproduction frequency,sex ratio, growth rates, growth performance indices, condition factors and natural mortality of red claw crayfish (Chreax quadricarinatus, von martens,1868) in lake kariba, Zambia

Abstract

The research was conducted from Lake Kariba because Lake Kariba is the largest man-made Lake in Zambia that has diverse ecological habitats that are rich in fish biodiversity. Crayfish were sampled from Kabbyobbyo and Mundulundulu in Siavonga. A total of 639 C. quadricarinatus samples were collected from Lake Kariba between November and December, 2022. Traps, locally called Kamono, were used to collect Crayfish. Length-weight relationships were determined by linear regression in Microsoft Excel to determine growth rates, r 2 and allometric growth forms. Reproduction frequencies of the sampled Crayfish were determined using length-frequency histograms. The growth performance indices, Condition factors and natural mortality parameters were determined from the linear regression of the length-weight relationship. The results showed that Crayfish is a multiple spawner and it has a sex ratio of 1:1. The growth performance indices ranged between 2.6 to 4.6. Natural mortality coefficients were less than 1.0 and the Condition factors were all above 1, suggesting good adaptability to the habitat at Lake Kariba.