The joy, tears of fish cage farming in Lake Victoria

James Omollo stares with pride across the expansive Lake Victoria and points at two fish cages which have transformed his life.

Fish cage farming has turned into a thriving business which meets the demand for fresh fish in the local market in the wake of dwindling stocks in the natural waters.

“As long as I can fend for my family and make an income,” says Omollo, “then I plan to have more cages in the lake.’

The floating fish cages technology was harnessed in 2013 after trials were successfully conducted at Dunga beach, Kisumu County, by Kenya Marine and Fisheries Research Institute (KMFRI).

Currently, fish cage farming is practiced in five riparian counties of Migori, Siaya, Homa Bay, Busia and Kisumu.

In the beginning, fish cage culture presented itself as a new socioeconomic frontier with good prospects for income in Lake Victoria, besides conserving declining wild fish stocks.

However, Dr Chrisphine Nyamweya, the assistant director at KMFRI, observed that the rising fish cage culture as forms of investments lead to environmental degradation besides threatening natural fish production in the lake.

“The practice brings about the discharge of particulate and dissolved nutrients from uneaten waste feed, faecal matter, and excretory products which are bound to negatively impact the fishery environment,” Dr Nyamweya explained.

He adds that the nutrients are toxic in the lake as they increase pollution thus the haphazard installation of cages is spelling doom for the lake’s ecosystem.

Data at KMFRI shows there are over 6,000 fish cages on the Kenyan portion of Lake Victoria with each cage having the capacity to produce one tonne of fish annually.

According to KMFRI, the current aquaculture capacity in the lake is 60,000 tonnes of fish annually against annual wild production of fish which stands at 100,000 tonnes.

“The cage culture is growing rapidly and will soon overtake the wild and natural fish production in the lake,” notes Dr Nyamweya.

According to the assistant director, the space for natural products is shrinking at an alarming rate, meaning fish cage farming will eventually take over the lake.

The changing dynamics of Lake Victoria fisheries over the last decade have led to an altered ecosystem.

The expansion of fish cages in the lake reflects changes over the last century.

Dr Nyamweya said fish cages are common systems in freshwater and marine environments, and have become popular due to their flexibility in placement, ease of expansion and high return on investment.

Environmentalists are worried that fish cage farming is a threat to the lake’s ecosystem and to important species.

Michael Nyaguti, the chairman of Magnum Environment Network, protested that many cages are installed in the lake without following regulations.

“We suspect that some fish kills are as a result of waste feed which is highly polluting the waters and uncalled for,” he says.

Nyaguti adds that farmed fish do escape and interact with other fish in the wild resulting in the spread of diseases and parasites.

With all the risk factors, says Nyaguti, the cages will end up overtaking the natural fish production which will alter the entire lake ecosystem.

KMFRI data shows that species like Tilapia have already shrunk by more than 50 per cent in the last decade but the resilient Nile perch shrunk by 23 per cent. The bigger Nile Perch has been resilient because one Nile Perch can produce 17 million eggs compared to Tilapia’s 300 eggs.