Zimbabwe, Zambia

Kariba & Middle Zambezi

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Alien crayfish colonise Kariba

Alien crayfish colonise Kariba

Alien crayfish colonise Kariba

The Australian Red Crab Crayfish has become prolific in the Eastern Basin of Lake Kariba, with populations spreading as far west as Chilala. Explanations as to how the crayfish were introduced into the lake are vague, but suggestions are that specimens escaped when a storm damaged cages of crayfish on a commercial project in Siavonga.

The extent of the current population in the Lake is also uncertain, with both the University of Zimbabwe’s Lake Kariba Research Institute and the National Parks-run Lake Kariba Fisheries Research Institute currently running research programmes.

With little reliable information it is unknown what impact the alien population will have on the established ecosystem, but there are fears that the crayfish will have a negative impact on fish stocks such as the Red-Breasted Bream (Tilapia rendalli). Crayfish eat large amounts of live or decaying plant or animal matter which may include other species’ nests, and habitats crucial for breeding and feeding. The crayfish are fast breeders and able to colonise a large area fairly quickly.

The Red Crab Crayfish resembles lobster but lack the powerful claws on their front set of legs. They grow to an average size of 45-50 cms and at 2-3 kgs in weight they potentially offer a lucrative commercial opportunity. Crayfish are low in fat, cholesterol and salt and so are a nutritious alternative to current protein staples. A commercial operator has been awarded a license to harvest the crayfish but to date has not commenced operations.

Crayfish competition!
Steak and Lake crayfish recipe competition

Read more on crayfish in the March 2013 issue:
Crayfish invasion worries experts

Read more articles from this issue:
Zambezi Traveller (Issue 11, Dec 2012)

Read more about the region in our destination guide:
Kariba & Middle Zambezi