From Fish-Skin Shoes to Sausage, New Uses Found for Kenya’s Nile Perch : Ecology: Population boom of the voracious species has economic potential, but it has contributed to loss of biological diversity in Lake Victoria.

Kenyan fish technologist Joseph Ogunja holds up a reptilian-looking piece of leather and points with satisfaction to a photograph on his office wall. It shows three styles of shoes, a purse and a belt, all made from similar hides.

The tanned hide of Nile perch caught in Lake Victoria hasn’t yet taken the fashion world by storm, and Ogunja is still refining a recipe for perch sausage. But in the last six years, he and his 20-person team have helped boost the demand for Nile perch products, edible and otherwise.

“Whether this will be positive or negative in the long term remains to be seen,” said Richard E. Leakey, director of the Kenya Wildlife Service. “In the short term, there are serious issues that have to be addressed.”

Although the perch are an important protein source for the residents of Victoria’s shores, he said, they are also a powerful contributor to the loss of biological diversity in the once-rich lake in Kenya, Tanzania and Uganda.

The Nile perch, a predator that can grow up to 6 feet long on a diet of smaller fish, was first released into 26,828-square-mile Victoria--the world’s second-largest freshwater lake--in the early 1960s.

For 20 years, the perch was commercially insignificant. In the early 1980s, its population suddenly exploded and it became the most abundant species in the lake.

“Today the Nile perch is making Lake Victoria the most productive lake in the world, yielding 220,000 to 330,000 tons of fish per year,” said biologist George Ssentongo of the United Nations Food and Agriculture Organization (FAO).

He and other scientists fear, however, that the perch population may crash as suddenly as it boomed. Few of them are willing to bet on its future.

The boom in perch has been accompanied by accelerated deterioration of the algae-choked and oxygen-depleted lake. The perch’s voracity has taken an enormous toll on Victoria’s native fish species, at least half of which are now believed to be extinct.

Among the perch’s victims have been native plant-eaters that used to help keep algae in check.

Their loss, combined with increased nutrients pouring into the lake--human waste, agricultural runoff and acid rain--increases the production of algae. This in turn contributes to the growing shortage of oxygen.

Regional climate change may also be a factor. Warmer or rainy seasons fail to stir and re-oxygenate the bottom waters of Lake Victoria.

The traditional fishery on which 30 million people have relied for protein is devastated.

“The sudden change in the fishery was quite a concern, because the Nile perch was new to the people,” Ogunja said. Village women accustomed to frying or sun-drying whole small fish-like labeo or tilapia didn’t know how to process or cook the big, oily perch.

“There were no commercial processors, local customers weren’t happy with the taste, and there was no market for it elsewhere,” Ogunja said. “Most of it was being left on the beach to rot.”

With support from the FAO, Ogunja and his team went into action in 1986 to try to ensure that the lake’s new bounty didn’t go to waste. Their work was often as elementary as teaching villagers how to fillet fish or holding seminars for hotel cooks in Nairobi, the Kenyan capital, on how to prepare cold smoked perch appetizers.

Team members persuaded an English brewery to buy dried Nile perch air bladders to supplement catfish air bladders used as filters in making beer. Companies in Hong Kong have begun bidding on perch bladders for soup.

In his laboratory at the Kenya Marine and Fisheries Research Institute on the lake shore in Kisumu, Ogunja is working to develop frozen soups and minced-perch products.

“We have a large Muslim population, and they don’t eat pork sausage,” he said. “We think there might be a market for perch sausage.”

Very little Nile perch rots on the beach these days, but success in opening up new markets has created new problems at home.

Since Ogunja’s team started its work, more than two dozen plants have been built in Kenya and Uganda to process and export fresh frozen Nile perch fillets to markets such as Israel and the Netherlands. But this has pushed the price out of reach for most locals.

“The main role of fisheries should be to provide protein for the community first, then to provide foreign exchange,” said James Ogari, the research institute’s deputy director for inland waters. “But the trend as it is now is in reverse. I don’t know what the poor man is going to eat.”