Zimbabwe, Zambia

Kariba & Middle Zambezi

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Crayfish invasion worries experts

Crayfish invasion worries experts

Kariba rayfish invasion worries experts
Kariba rayfish invasion worries experts

 

In addition to a growing population of Australian Red Claw Crayfish (Cherax quadricarinatus) - see the December issue of the Zambezi Traveller Alien crayfish colonise Kariba - in the eastern basin of Lake Kariba, it is unclear whether another species, Cherax destructor is also breeding in the lake.

Cherax destructor, a burrowing relative of the Red Claw, could potentially cause damage to the Lake’s hydroelectric infrastructure as it buries itself in the lake bed and banks.

Chief Ecologist from the University of Zimbabwe’s Lake Kariba Research Institute, Crispin Phiri, has confirmed the rapid population growth of the Australian Red Claw crayfish, especially around areas near human habitation and near slipways and harbours. A lack of funding within the Institute has hampered thorough research into the infestation and the only feasible way of dealing with the issue seems to be commercial trapping.

Despite the crayfish reaching prices around $9.00 per kg in shops, it is not yet a popular source of protein for local fishermen in the Lake Kariba area. Permits will be required to trap and sell the crayfish but it is unclear what the costs and regulations will be.

There is potential danger that the crayfish will be illegally captured and relocated into freshwater areas nearer Harare and larger urban areas to facilitate supplying these markets. This could prove disastrous from an ecological standpoint as the crayfish has no predators in the wild, breeds quickly and voraciously devours live or decaying plant or animal matter to the detriment of local species.

“We don’t have the resources on the ground to license or police exploitation on the right scale at Kariba,” says Phiri. “The important thing right now is we don’t want people to introduce it elsewhere.”

Zambezi Traveller invites comments and contributions on this issue. What is the best way forward:-

    •    Make it easy to catch and sell the product with minimum restrictions to quickly utilise and reduce populations?
    •    Regulate the industry so that breeding is tightly controlled?

Email your thoughts to The Editor, Frances Jackson, frances@zambezitraveller.com

Crayfish Recipe
Recipe: Braaied Red Claw

Crayfish competition!
Steak and Lake crayfish recipe competition

Read more on crayfish in the December 2012 issue:
Alien crayfish colonise Kariba