Fish stocks dwindle as pollution rises

By Antony Gitonga

Back in the early 80s, Lake Naivasha used to be the main supplier of fresh fish to Nairobi and underlying towns in the Rift Valley.

Thirty years down the line, the popular Tilapia species from the lake is no more and fish supply cannot sustain even the fishermen who work the lake.

Instead, an unpopular species known as Common Carp has found its way into the lake.

The lake is under attack from all corners, with poaching and pollution playing a major role in depleting the Tilapia stock.

Every year, from June 1 to August 31, the lake is closed from fishing to aid re-stocking, a move opposed by the fishermen.

Unlike in the ‘80s when the lake supported several hundred fishermen, the number has been reduced to 50 boats with ten nets each.

The lake ecosystem has adversely affected by agro-chemicals used in the horticultural farms and increased human activity around it.

Researchers claim the chemical run-off from the farms around the lake, which use its water for irrigation, and the town’s sewage are the main killers of fish.

In a report titled ‘Towards Conservation of Lake Naivasha Fisheries’ by Mr George Morara from Kenya Marine and Fisheries Research Institute, destruction of the habitat is the main threat facing fisheries.

In his recommendations, Morara says the annual three-month ban is appropriate, adding that more efforts should be made to protect the breeding grounds.

Mr Dalmas Oyugi, a senior lecturer at Kenya Wildlife Service and Training Institute, says as the lake levels drop, so does the amount of fish catch.

He says the unpopular Common Carp originated from Europe and Asia and calls on fishermen to embrace the unsavoury species as Tilapia faces extinction.

According to Mr David Kilo from the Lakes Anti-poaching Unit, the three-month ban was meant to increase the Tilapia numbers, a move that has failed.

"Currently, getting Tilapia from the lake is near impossible and we wonder what benefit the ban is serving," Kilo says.

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Kilo is, however, quick to note that poachers are a major threat to the fishery, as they have been fishing in breeding zones and using undersize nets.

According to the Assistant Director of fisheries Nicholas Nthekentha, the annual ban will continue. "We have realised that the ban is effective and we urge the fisherman to be patient as it is meant to benefit them," Mr Nthekentha said.