Declining lake stocks, China fish imports threaten local fishers

As fish from China drive fishermen out of business, the dwindling catches from Lake Victoria have left an insufficient supply of fresh fish.

Before its waters were polluted, Lake Victoria was the world’s second largest freshwater lake – known for its huge stock of fish until 1950s when nature and man-made calamities conspired against it.

Researchers agree that fish in the lake are facing serious challenges due to pollution, destruction of wetlands, over fishing and destruction of breeding grounds.

The Kenya Marine and Fisheries Research Institute reported that fish stocks are declining at an alarming rate due to destruction of wetlands.

With the indigenous lake-shore and swamps cleared to pave the way for settlements and as tea, coffee and sugar plantations led to topsoil being washed into the lake, the rise of both commercial and local fishermen led to the decrease of the indigenous Tilapia.

ECOLOGICAL BLUNDER

This was followed by what is now seen as an ecological blunder: the introduction in 1950s of the Nile Perch, a voracious predator which eats small fish.

Thought to have been introduced in mid-1950s at Jinja and Entebbe, the Nile Perch spread from their points of introduction and moved clockwise towards the Nyanza Gulf (Winam) before taking over the entire lake.

Although a 1971 UN study found that the Nile Perch had overtaken the Tilapia it also found that the lake’s ecology had not been altered.

Some 10 years later, another study found that the that the indigenous colourful cichlids’ population had dropped from 80 per cent of the lake’s fish biomass to a mere one per cent described by Boston University scholar Les Kauffman as “the greatest vertebrate mass extinction in recorded history.”

While the Nile Perch was supposed to form a thriving fish industry, recent studies say that overfishing and oxygen depletion at lower depths of the lake now threaten the artisanal fisheries and biodiversity with more than 200 indigenous species said to be facing possible extinction.

As a source of food, energy, drinking and irrigation water, shelter, transport, and as a repository for human, agricultural and industrial waste, the lake is now considered environmentally unstable.

Dr Ally-Said Matano, the executive secretary of L. Victoria Basin Commission told the Nation that with the population of riparian communities growing, multiple activities have increasingly come into conflict with the environment.

“In the last three to four decades, there used to be over 500 species in the lake but over time with the fisheries dynamics including introduction of the Nile Perch and growing culture for fish eating has affected this. Increased pollution is also a major factor,” said the environmental expert.