Just what is killing fish in Lake Victoria? Residents ask

Panic has gripped fishing communities around Lake Victoria over continued unexplained deaths of fish which is being swept ashore by waves.

The death of thousands of the Nile perch (Mbuta) in the lake is threatening the livelihood of the fishing community in Nyanza and Western regions.

According to fishermen at Marenga Beach in Busalangi, the death of fish threatens the export industry.

The deaths have also raised concerns about the safety of fish from the regional lake.

The cause of death is yet to be established although it is speculated that the fish could be dying due to climactic changes.

"There are few isolated cases in Busia but the situation is worse on the Ugandan side and parts of Nyanza," said Mr Robert Anema, the Marenga Beach manager.

Mr Antony Bahati, a fisherman, confirmed that they are encountering several dead fish in the lake.

In Uganda, dead fish were last month found on the beaches or floating in water at Gerenge and Kigungu landing sites in Entebbe, Wakiso District, Uganda.

Fish appeared ‘drunk’

A similar phenomenon was reported last month at Philomena landing site in Mwanza, Tanzania, with local fishers saying fish that appeared "drunk" were swimming close to the water surface but were not dead.

In Homa Bay County, the phenomenon has been witnessed on beaches in Suba and Mbita sub counties.

The county government of Homa Bay said it is working with Kenya Marine and Fisheries Research Institute (Kemfri) to establish what is killing the fish.

Agriculture and Fisheries Executive Aguko Juma said samples of dead fish are being collected for tests.

Oxygen deficiency

Dr Christopher Aura, deputy director in charge of Fresh Water Systems Research at Kemfri said the deaths of the fish could be linked to oxygen deficiency in the water.

This, he said is caused by a process in which cold water with low oxygen level replaces warm water where the fish live.

"This normally happens when there is a sudden change of weather affecting the lake. The longer the water mixes the more the fish die," said Dr Aura.

Meanwhile, officials from the fisheries department in Homa Bay are also investigating a new practice that is taking the fishing industry by storm — the sale of fish bladder, popularly known as mondo.

Fish bladder trade

Trade in fish bladder is considered more profitable than sale of fish itself.

Mr Juma said his office has received complaints from boat owners that fishermen are discarding fish in the lake after removing bladders, which are sold in foreign markets.

"It is an illegal activity to discard dead fish in the lake. It is a practice that is becoming common among our fishermen,” he said.

Meanwhile, fishermen have been warned against picking dead fish for sale. Mr Juma said the fish may harm humans f consumed.

Reported by George Odiwuor, Shaban Makokha and Elizabeth Ojina