HOMA BAY, Kenya — At dawn on the Winam Gulf, the fishermen of Homa Bay no longer row out to cast nets. They motor out to feed fish that are waiting for them.
Kenya’s cage aquaculture industry on Lake Victoria, almost nonexistent a decade ago, produced 54,000 tons of tilapia last year, the Kenya Marine and Fisheries Research Institute reported last week, surpassing for the first time the wild catch from the Kenyan portion of the lake. About 9,000 cages, each a floating ring of netting holding up to 3,000 fish, now dot the bays of Homa Bay, Kisumu, Siaya and Busia Counties.
The boom is a response to decline. The wild tilapia fishery, battered by overfishing, invasive water hyacinth and the predatory Nile perch introduced in the 1950s, fell from 25,000 tons in 2000 to under 10,000 by 2019. Kenya, with a population that eats fish faster than the lake can grow it, became a net importer, buying frozen tilapia from China.
“We were watching our fish arrive at the market in boxes with Chinese writing,” said Benta Achieng Otieno, 38, who with 11 other women formed a cooperative in 2021 that now runs 60 cages near Mbita. “We said, we have the lake right here. Let us farm it.”
The cooperative harvests about 40 tons a year and sells to traders who truck the fish to Nairobi overnight. Ms. Otieno said each member clears about 30,000 shillings a month, roughly $230, three times what fishing families earned a decade ago. A hatchery and feed mill in Kisumu, built with Dutch development money, employ 300 more.
The growth has outrun regulation. The county governments issue cage licenses, but a mapping exercise by the research institute this year found that a third of cages sit in areas designated as fish breeding grounds or shipping channels, and that cages in the shallow, poorly flushed Winam Gulf have raised nutrient levels enough to trigger algal blooms. Two mass fish kills in 2025, each wiping out hundreds of cages, were blamed on low oxygen.
“Aquaculture saved the economy of the lakeshore, and it can also poison the lake if it is done in the wrong place,” said Dr. Erick Omondi Ochieng, a limnologist at Maseno University. “The gulf is already full. The question is whether the next 9,000 cages go into deep water or on top of each other.”
There is also the matter of ownership. Large investors, including a Nairobi-based company with 1,200 cages, have secured prime sites, and traditional beach management units complain that fishermen who once worked the water freely are now told to keep their nets away from private cages. A bill before the Kenyan Senate would reserve 40 percent of cage sites for community groups.
Ms. Otieno’s cooperative has applied for a deep-water site three kilometers out, which would require a bigger boat. “The lake is big,” she said, scattering a scoop of pellets that the water instantly boiled around. “We just have to go farther into it.”
A version of this article appears in print on Oct. 12, 2026, Section A, Page 1 of the European edition with the headline: On Lake Victoria, Floating Cages Revive a Fishing Economy the Lake Itself Could No Longer Feed.
