Chinhoyi Bureau — Fears abound that fish population in Lake Kariba might have declined significantly following the escape of a predatory fish breed called crayfish from some ponds in Zambia. The Australian red claw crayfish are so aggressive and they disturb the breeding of kapenta and other fish breeds.
The crayfish reportedly escaped from ponds where they were bred in Zambia's Siavonga area following a storm that left the cages open some years back.
Sources in the industry said they had so far registered a steady decline in the catch over the years with indications that this year would be no better.
"We have been in the kapenta fishing business for a long time but yields are going down. This is the peak period for kapenta fishing but we are hardly getting anything. We do not know what is going on," said a source.
From a peak of about 19 000 tonnes of kapenta fish annually in 1997 to nearly 9 000 tonnes in recent years, the decline has not been received well by fisheries who earn their living from the lake.
Although not direct consumers of kapenta and the world famed tilapia fish, crayfish scour the lake bed in search of decomposing matter in the process disturbing fish nests and food.
Some people have, however, seen an opportunity and are fishing the lobster-like fish which can measure up to 50cm and weigh anything up to 3kg.
The Zimbabwe Parks and Wildlife Authority has reportedly started issuing permits to fishermen in the hope of managing their population.
The authority's spokesperson Ms Caroline Washaya-Moyo confirmed the existence of the crayfish without giving further details on what steps were being taken to address the situation.
However, sources said permits were being issued to individuals who were using cages to harvest the fish in the hope that this would result in a decline of the fish population.
The fish breeds fast which has seen it spreading in the lake to the extent where they are commonly seen on the shores.
There are also fears in some cycles that the decline could result in over-fishing which has affected breeding and replenishment.
Kariba currently has about 365 fishing rigs operating every night from the Zimbabwean side while Zambia has an additional 600 rigs employing nearly 5 000 people.