Fish reared in metal cages, artificially fed and harvested only when they mature.
Anyanga Beach in Siaya County is scenic, with the water stretching as far as the eyes can see.
It is one of the most popular beaches on the shores of Lake Victoria, the others being Dunga and Usenge.
Boats row in and out of the lake, some full of fish while others carrying fishermen with their tools of trade venturing into the water to try their luck as fish stock has dwindled.
It is early evening when we arrive at the beach. Seeds of Gold is here to visit farmer Mark Owuor Orieny, who is engaging in fish farming inside the lake using a new method.
Orieny practices what is referred to as cage fish farming, a method that is mainly done inside large water bodies like lakes, dams and rivers.
Under the method, the fish is reared in metal cages, artificially fed and harvested only when they mature.
“I have installed 16 fish cages inside the lake. Eight cages have about 2,000 fingerlings each and the others hold mature fish of between five and seven months old. In total, I rear about 32,000 fish under the system, which is also known as floating cage aquaculture,” says the 43-year-old farmer as we ride a motor boat to access the cages.
Inside the boat are 20kg of fish mash, life jackets and a jerrican of petrol just in case the boat needs to be refuelled.
It takes us about 20 minutes to reach the metal cages. The 16 structures suspended in water are a spectacle to behold.
Arranged in a straight line, one may think they are a bridge, only that they start and end inside the lake.
“It cost me Sh65,000 to build each cage. The materials I used include 250-litre plastic drums, wire mesh and anchors. The drums act as wave breakers,” says Orieny, who makes and installs the cages himself before putting in the fingerlings that he buys at Sh5 from Mabro Feeds Company in Usenge.
He uses waterproof cement, ballast, steel, wire mesh and sand to construct the cages on land before transferring them in water.
The structures weigh between 150 and 250kg and are two metres squared.
SURVEY THE WATER
However, there is no ideal cage size as one can construct them as big as they wish. One anchor holds up to 10 cages, each 2m from the other.
“The cages must be placed in rows of 10. After the tenth cage, two more 250-litre tanks are put,” explains Orieny as he feeds the fish.
Before installing a cage inside the lake, Orieny says one must survey the water to know the best place to place them.
“You have to know the wind direction to align the cages well. You also need to consider the nutrient content, rate of water flow and depth of the waters,” says the farmer, who holds a Masters degree in Environmental Management, adding that the water depth has to be at least 6m to leave two metres under the cage.
He rears only male fingerlings to avoid overbreeding and help the fish mature faster.
“When I started rearing fish in cages in 2013, I realised that they were multiplying faster because they were not mono-sex.” A good number of them died as they were competing for oxygen and food.
He sought assistance from Kenya Marine and Research Institute (KMFRI) experts and he was advised to reduce the number of fingerlings in a cage to not more than 2,000. Congestion leads to diseases like fin rot.
“Fin rot makes both the fins and the tail to decay such that the fingerlings or the fish cannot swim,” says Orieny, who spends Sh10,000 on buying fish feeds every month.
Dr Tsuma Jembe, a Senior Research Scientist at KMFRI, says bacterial tail and fin rot are common diseases which attack fish reared in both ponds and under the cage system.
He says fin rot is associated with polluted and unsanitary conditions in hatcheries.
“Though bacteria are the causative agent of tail and fin rot, pathogenic protozoans and fungi may be involved. The infection may also spread on the body surface,” says Dr Jembe.
Orieny harvests his fish after seven months, and since they are in several cages, he harvests every day all-year round.
“Every month, I harvest about 2,000 fish that weigh an average of 500g. I sell each at between Sh150 and Sh600. If you compare these returns with that of ponds, cage fish farming is the way to go since fish live in a natural habitat thus multiply faster in cages.”
He sells the fish to traders from Kisumu, Vihiga, Kakamega, Siaya and Bungoma counties, majority who wait for the commodity by the lakeside.
He learnt the method of farming while studying for his Masters degree in Britain in 2000.
“I came back from Britain after working there for 13 years,” says Orieny, who owns two motor boats that costs Sh50,000 each which he uses in his fish business.
To boost security and prevent his fish from being stolen from the cages, Orieny has employed guards to patrol his farm.
This is beside the two workers who feed and harvest the fish for him, and eight others who work on his omena business. He pays them as average of Sh8,000 per month.
Besides fish farming, he constructs cages for individual farmers and institutions.
Last year, Jaramogi University of Science and Technology (JUOST) awarded him a tender to build fish cages in the institution’s Sakwa ground, which borders Lake Victoria.
He constructed 11 cages with each costing Sh80,000.
Orieny intends to increase his cages to 40 to boost production. He also plans to start a fish filleting plant for value addition and processing for export.
“Cage culture is serious business, it cannot be done in ponds because they are shallow. It is only done for large-scale commercial farming,” Dr Jembe warns.
The fisheries expert says one of the most significant factors to consider while starting cage fishing is the depth of the water body. Ideally, the cage depth should be about 8m deep.
The other factors are circulation of water currents, which may be hard to determine in ponds.
“One should also look at temperatures and the presence of dissolved oxygen to enable fish to breathe. All these conditions cannot be met in a fish pond. The ocean or sea are also not a viable place because of the many predators.”
He observed that farmers don’t need a licence to practice the method of farming in Lake Victoria or any other water body.
“However, since we share Lake Victoria, we are trying to work with Uganda and Tanzania to come up with a policy to practice cage fish farming. A team of senior research scientists from Kenya, Uganda and Tanzania met in October last year to discuss how best to manage cage culture in Lake Victoria,” says Dr Jembe, who was part of the team.
“We need policies because you can’t practice it everywhere like on breeding sites and maritime routes where ships are passing.”
The advantage of cage fish farming, according to Dr Jembe, is that fish live in their natural habitat.
“The cages offer fish protection from predators, there is controlled feeding and harvesting. Overall, the method is cheaper as compared to building ponds.”
With fish stock in Lake Victoria and others like Lake Naivasha dwindling due to over-harvesting, the expert reckons cage fish farming is the best way for fishermen to get regular supply of the commodity and control the practice.
Raphael Mbaluka, the Principal Fisheries Officer in the Ministry of Agriculture, says the government is working on a plan to enable farmers to engage in fish farming in water bodies like rivers, dams and lakes.