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Nile Perch
Hoping to give the local fishery a bigger fish to catch, in 1954 the British colonial administration introduced the Nile perch into Lake Victoria.
Bountiful waters
At 26,560 square miles -- nearly the size of West Virginia --
Lake Victoria is the largest tropical lake anywhere. At one time it was the site of the world's largest concentration of cichlid species -- freshwater fishes famous for their ability to evolve rapidly in new niches. The 300 cichlid species in Lake Victoria provided much of the protein consumed by people living along the lakeside.
Fatal choice
The introduction of the Nile perch seemed a good move at the
time: most cichlid species weighed only a few ounces, but large perch may weigh up to 300 pounds (125 kg). Instead of being a blessing, however, this interloper soon became a curse. In short order, it fundamentally changed the lake's ecology by eating, to the point of extinction, at least half of the cichlid species that once lived there. At present, cichlids constitute less than one percent of fishes caught in Lake Victoria.
Lake Victoria
Now that many species of algae-eating cichlids are gone, the waters
of Lake Victoria are frequently choked with algal blooms. Similarly, several insect species, once kept under control by cichlid predation, now breed in unprecedented numbers. The Nile perch may have caused its own doom: having eaten its way through all potential cichlid prey, it must now rely on a single species of small freshwater shrimp. How long will the shrimp hold out? No one knows. The fate of Lake Victoria, and with it the livelihood of the human populations that depend on it, hangs in the balance.
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