Agricultural effluent and untreated wastewater being discharged into Lake Victoria are major contributors to the destruction of its fragile ecosystem.
Left unchecked, these discharges could lead to the lake's death, scientists have warned.
According to Dr Ronald Semyalo, a hydrobiologist, blooming of algae on the surface caused by pollution with fertiliser and agricultural wastes is a major cause of the reduction of oxygen available for fish and other aquatic life forms in the lake.
"The growth of algae has caused a reduction in the population of fish and signals the slow death of the lake," he said.
Dr Semyalo said the lake was in danger of dying due to leakage of fertiliser, pesticides and industrial waste into its waters, adding that more needs to be done to ensure the lake survives for future generations.
In a study on the quality of water in and around Lake Victoria, Prof Charles Willem, Dr Charles Niwagaba and Mary Aukurut found that the water quality in the Inner Murchison Bay on the northern shores of Lake Victoria in Uganda has deteriorated over time due to pollution.
The report also showed that commercial and industrial establishments had the highest pollutant concentrations.
This has not spared fishing. According to President Yoweri Museveni, illegal fishing had weakened havoc in the country's fish processing industry, noting that out of the 21 fish factories that were operational 10 years ago, only eight are operating today.
"The factories were annually processing a total of 36,614 tonnes of fish worth $144 million in 2007. Today, the surviving factories earn only $123.1 million," he said on August 26.
Fish catchers, processors, traders and government officials involved in Uganda's fishing sector have recently been saying that fish stocks in Lake Victoria are declining.
An October report by the Lake Victoria Fisheries Organisation, a Jinja-based research body, says that the Nile Perch population has dropped by up to a quarter while that of omena has almost halved (49 per cent).
Research established that the Tanzanian portion of the lake, which is the largest of the three nations, registered the sharpest drop, with fish stocks declining by 33 per cent, followed by Kenya at 31 per cent and Uganda at 13 per cent.