The Ministry of Agriculture has revealed that Uganda suffered most in the East African region in the recent surge in fish kills that saw piles of dead fish floating on lakes.
The mass death of fish, has been reported in Uganda on Lake Kyoga and Lake Victoria.
However, no significant deaths were reported in neighboring Kenya and Tanzania which share Lake Victoria.
The agriculture ministry Permanent Secretary Pius Wakabi Kasajja revealed on Wednesday that on Lake Victoria, the fish kills were mostly concentrated in Wakiso district.
“Inquiries from Kenya report no significant fish kills observed on the Kenyan side with only one landing site (Nyandihiwa) reporting fish kills of about 200 kg in December 2020 which was a normal occurrence as such happens annually,” Kasajja said.
“On Tanzania side, fishers from Mwanza contacted reported no mass fish kills.”
The mass fish kills are being attributed to recent changes in weather patterns, after laboratory tests confirmed the fish were not poisoned.
“Samples that were analyzed were picked from Kasenyi landing site, Kigungu landing site, Bugonga Landing site and behind Wagagai flowers. Tests for organophosphates, organochlorines and pyrethroids (Poisons) all turned out negative,” he said.
It is now believed that the fish were killed by lack of sufficient oxygen in the water as a result of widespread thermal stratification patterns.
“Dissolved oxygen profiles showed instances of anoxia or below critical levels of dissolved oxygen occurring at the bottom depth zones. Reports by Directorate of Water Resources indicate Dissolved Oxygen (DO) as low as 3m/l in some places reflecting anoxic conditions,” he said.
“Last Monday 4th January 2021 there was a heavy storm in Entebbe. It is possible that the recent changes in weather conditions could have triggered mixing of the lake, an event that could lead to fish kills. The deaths are reported near the shores where waters are shallow and usually nursing grounds for young Nile perch hence the high number of death among the young fish.
The most affected species the PS said was the Lates niloticus (Mputa/Nile perch).
“The weight of dead fish has been ranging between 15 to 20 kg per head with the record of 100 kg as the biggest”
As such, the PS assures that the fish kills are a normal phenomenon, that occurs almost every year.
“It also has no impact on the taste quality of the rest of the fish in the lake. This is to therefore reassure fish consumers that there is no harm in consumption of Fish from the lake.