Lake Victoria's Mysterious Mass Fish-deaths

21 Feb 2021 by The Water Diplomat
KIGALI, Uganda

The governments of Kenya, Uganda and Tanzania have reported that within the last 2 months roughly 100 tonnes of fish, mostly of the freshwater species Nile Perch, have died due to unknown causes in Lake Victoria which borders all three countries.

The mass deaths of Nile Perch, which are valued at between 10 Million and 15 Million Uganda Shillings (UGX) ($2732 - $4,096 USD) per tonne depending on their weight, has cost the government an estimated $409,840 USD in revenue so far – however, it could potentially become much more.

Joyce Ikwaput Nyeko, Uganda's acting director for Fisheries Resources in the Ministry of Agriculture, Animal Industry and Fisheries said in an interview on 9 February: “I know we have lost more than 100 tonnes [of fish]; we are still waiting for reports from the field teams and that is how we will also know the revenue we have so far lost.”

Over the past couple of months, mass amounts of dead fish have been reported to have washed ashore, particularly in the districts of Wakiso, Buikwe, Buvuma, Kalangala, Masaka and Kyotera, leading to complaints from local residents of the foul odour emitting from the rot.

The deaths are driving down the cost of fish both on the local and international market which, combined with a low demand for fish due to the COVID-19 pandemic, poses a serious threat to the fisheries sector. According to local fishermen and women, the dead Nile Perch are also driving away other species of fish making it more difficult to catch produce.

Paul Orina, a freshwater agriculture research scientist at the Kenya Marine and Fisheries Research Institute (KMFRI), described the fish deaths in Lake Victoria as a normal occurrence citing a similar situation that happened in the lake five years ago, although this only lasted one week.

According to Orina, the deaths of Nile Perch can be attributed to changes to the structure and condition of Lake Victoria mainly due to winds and floods which has reduced oxygen levels in the water. He cited the high oxygen demand of the Nile Perch species as the reason why they are being disproportionately affected.

Scientists have warned that Lake Victoria is at risk of dying due to overfishing and pollution, affecting human livelihoods. In a recent incident soldiers from the Fisheries Protection Unit arrested at least 20 fishermen on 5 February on suspicion of engaging in fish poisoning activities.

Investigations into the cause of the deaths are ongoing according to Tom Bukenya, the commissioner for fisheries regulations and quality control assurance. As reported by Uganda's Daily Monitor, Bukenya said: “We have heard allegations from different people that it could be poison but the first samples we took to laboratory ruled out poisoning, further investigations are being carried out to establish what is exactly causing this mass deaths of Nile Perch,” he said.

In the meantime, warnings about consuming dead fish have been circulated.