Lake Victoria pollution causing Kenya Sh40bn annual revenue loss

The incessant contamination of Lake Victoria due to human-related activities is continuously denying the country revenues estimated to be more than  Sh40 billion annually.

Kenya Marine and Fisheries Research Institute (KMFRI) Fresh Water Research Director, Christopher Aura revealed that the loss is attributed to pollution, high population density, and increased fishing pressure.

Aura reiterated that more than 60 per cent of fish production in Kenya and one per cent of captured fish globally comes from Lake Victoria with aquaculture and marine posting 14 per cent and 17 per cent respectively.

The world’s second freshwater body has the potential for an estimated annual production of 300,000 metric tons.

“The lake currently produces 115,000 metric tonnes valued at Sh12 billion on a declining trend annually compared to the year 2002 when it produced 200,000 metric tons," Aura said.

"In terms of individual fish size production, Omena (sardines) is now leading at more than 50 per cent, Nile Perch(22%), and Tilapia(3%).

“But on export value, Nile Perch is four per cent and Omena is three per cent.”

Aura was speaking during a virtual presentation to more than 20 journalists drawn from Media for Environment, Science, Health and Agriculture (Mesha) Kisumu Chapter at the Dunga Beach boardwalk on Saturday.  

KMFRI’s reconstructed data of April 2022 indicates an increasing trend of fishers’ efforts into the lake estimated at more than 40,000 out of whom at least 1,000 are women, 15,000 boats (crafts), more than 5,000 cages and illegal nets from 2014.

This, however, has seen a decline in how much each fisherman brings at home (Annual Catch Per Unit Effort).

On the fish kills phenomenon, Aura noted that is due to eutrophication which is the nutrient enrichment, contamination, or commission which is coming outside and inside the lake.

“Some of the cage farmers are not undertaking the Base Management Practices like the wrong location of cages, the types of feeds used, feeding fish when they are stressed," he said.

"Overstocking, overcrowding, uncleaning or unchanging of the nets. The low oxygen levels contribute to fish deaths mostly in cases of high temperatures (upwelling)."

Further, Aura explained the change in lake water to various colours that is due to algae formation which are microscopic plants found in water. 

“When you see green algae it is called chlorophyta and red algae is rodophyta that comes due to Algal Blooms as a result of increased nutrients enrichment,” Aura said.

Aura further said that concentrations of toxins in the fish are a threshold of lead and mercury, at which if they go beyond that threshold, the fish become unsuitable for human consumption. But, he assured that fish from Lake Victoria are safe for consumption.

“Our role is to conduct research, do capacity building and advice the relevant bodies to take action, but we don’t go to the management aspect for implementation," Aura said.

"We provide data and information on the population structure of fish and maximum sustainable needs. Similarly, we do enforcement on fisheries and feedback."

This further entails the collection of data on oxygen, temperature, chemistry, living and non-living organisms, and monitoring from field surveys and satellites to compare with climate conditions within the lake.

Sustainable lake use resource looks at estimated annual production e.g. capture, how much the lake can sustain to be in a utilisable manner (carrying capacity) and develop suitability scenarios.

This leads to climate risk factors like high temperature, precipitation, rainfall, flooding and prolonged dry seasons which need best management practices when exerting pressure on the lake.

Kisumu Water and Sewerage Company (KIWASCO) Managing Director Tom Odongo said its two treatment plants next to River Kisat and Nyalenda Estate are able to handle both the domestic and industrial waste to the required standards.

“They are not sewer treatment plants but Water Resource Recovery Centres where we recover the wastewater, treat it, make it environmentally friendly, and release it back to the water bodies. On domestic wastes, is that all of them goes to the sewer lines and ends up for treatment,” Odongo said.

“Our treatment plants face challenges from phosphates and nitrates. The soap we use is a major cause of phosphorus and we need to campaign against its use on soaps."

Odongo further emphasised that most industries around Kisumu City have good pre-treatment waste facilities in line with the Environmental Management and Coordination Act (ENCA).

Kisumu County Fisheries Director Susan Adhiambo decried the increasing number of beach management units (BMUs), wrong placement of the fish cages and insecurity after fish losses due to unemployment.

“There are 35 BMUs in the county and we control illegal fishing and nets. We managed to stimulate the fisher folks after incurring massive losses of close to Sh1 billion from their invested cages. In Ogal Beach, we procured 2,000 fish and 2,000 bags of feed to 91 cages,’’ Adhiambo said.

She further elaborated that they have helped the fish farmers stay afloat through Aqua Reach Initiative and partnering them with a local bank.

Magnum Environmental Network chairman Michael Nyaguti urged for the constant test of water coloration along the industrial sources.

A position affirmed by Kichinjio BMU vice chair Salim Abdallah who called for a speedy solution to the incessant fish kills and low catch in his area.

Based on KMFRI’s calculated maximum lake sustainable needs, it is proposing a reduction in fishers' effort by 36-45  per cent range, demarcation of fish breeding grounds (lake maternities) and surface area which are mainly found in the river mouth where the river enters the lake and bays.

Aura said they are proposing blue economic use of water hyacinth on biogas and electricity productions, and manual removal and have introduced spatial planning on (Cage Culture) where they have mapped out cages in suitable and more than  40 per cent in unsuitable areas, breeding grounds and water hyacinth.

“We have divided the lake into offshore and inshore (cage culture). Offshore are cages placed deeper at a depth of 10 to 40m made with strong steel and are recommended to house 407 square kms-11 per cent of the lake," Aura said.

"The other suitability is 782 which is 21 per cent of the lake can be used for cages with lower dimensions. Inshore suitability are cages with low dimensions 2m by 2m, 3m by 3m recommended carrying capacity area is 291."

Control of river, sewage, or industrial discharges by ensuring they must not discharge the wastes into the lake untreated by using pre-treatment points or tanks within their locality and checking on the Biological Oxygen Demand.

KMFRI has advised the county government on water supply and sanitation, better habits, and cleaner riparian cities, to reduce lake pollution. 

In this way, Aura observed, lake sanitation will promote tourism culture, sports, support fisheries tourism and build on conference tourism.

Lake Victoria Tourism Association chairman Robinson Ayah insisted on a multi-sectoral approach to promote the lake’s attraction sites, gastronomy (cuisine tourism) and conservation of the aqua system.