The Effect of Accidentally Introduced Red Swamp Crayfish (Procambarus Clarkii) in Kafue Fishery
[1]
Kingstone Moonga , Department of Fisheries, Ministry of Agriculture and Livestock, Kawambwa, Zambia.
[2]
Confred G. Musuka , Department of Zoology and Aquatic Sciences, The School of Natural Resources, The Copperbelt University, Kitwe, Zambia.
A study using semi-structured questionnaires, interviews and focus group discussion, was conducted to assess the effect of accidentally introduced red swamp crayfish (Procambarus clarkii) in Stratum IV (Namwala district) of the Kafue fishery. The study revealed that gillnets of 2 inches (50mm) and above were more effective in capturing P. clarkii. It was also clear that fishers faced greater challenges due to the emergency of crayfish as part of their by-catch since most of them did not consider crustaceans as food and hence, either returned them into the water or threw them away. In addition, fishers faced the problems of net tearing as they removed the crayfish from the nets as the organisms got caught through entangling. The crayfish posed problems of predating on caught fish, thus lowering the quality of the saleable fish. The crayfish had sharp chelates that caused undesirable biting effect, which resulted into injuries to fishers in their effort to remove the organism from the nets. It was also observed that the increase in crayfish was only noticed in the last 5-10 years. However, the numbers of the crayfish caught showed strong seasonal variation, with the hot season recording the highest numbers of crayfish per finfish with cold season recording the least and the rainy season having intermediate catches. The quantity of crayfish caught in gillnets, were also depth dependent, with the bottom setting being the most effective, the mid setting coming after that and top setting being the least. In a similar manner, nets set close to the shoreline realized increased levels of crayfish by-catches. Fishers also attributed low levels of finfish and crabs catches to the emergence of the crayfish.
Effect, Procambarus Clarkii (Red Swamp Crayfish), Accidentally, Kafue Fishery
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