Redclaw Crayfish

To what extent is the 1992 introduction of Redclaw Crayfish into the Kafue River in Zambia threatening the freshwater aquatic ecosystem, and therefore the fauna existing within the ecosystem?
1-Introduction:
The scope of this research investigation is to examine the geographical issue of the extent to which the 1992 introduction of Redclaw Crayfish into the Kafue River in Zambia is threatening the freshwater aquatic ecosystem, and therefore the fauna existing within the ecosystem. Kafue is a region in southern Zambia which the 2010 Kafue Trust survey found the resident population to be 219,000 people.
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The female will fertilize 300-800 eggs over a 6-10 week process, these figures vary due to water temperature. In fish farm conditions approximately 90% of one brood will reach a mature enough stage to be sold in market, however in its natural environment 30% of a brood will survive due to predators. On the other hand, in the Kafue river the juvenile crayfish face little threat due to the lack of predators. This information leads to the assumption that the survival ratio within the Kafue will be higher than rates in its native rivers of Queensland Australia. Another factor which contributes to the rapid population growth of the Cherax quadricarinatus is the species breeding season relative to the Zambian 'rainy season'. Zambia's rainy season occurs from November to February; therefore the Red-claw breeding season and rainy season coincide perfectly. During the rainy season the rivers in Zambia flood and dry riverbeds become full and running for approximately three months depending on the severity of rainfall. As this takes place the tributaries connecting waterways within Zambia open up and aquatic ecosystems are able to connect. This conjure is supported by the data released by the Kafue River Trust as the data suggests that the specie migrated over 100 kilometers through the Lufupa River system, a water way that is only fully connected during rainy season months. Therefore the Red-claw crayfish spreads and migrates via diffusion and young juveniles are transported down river. Whence this process is finished the cycle repeats annually. Therefore the population and area of which the alien specie occupies increases every year. The

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