 In the 1950s or 1960s, the Nile perch was released into the Lake Victoria. In just a few decades, the large, voracious predator has all but eliminated the other species of fish, turning the lake into an ecological wasteland. "But economically, it s good" -- and indeed, perch fillet is Tanzania s best selling export to Europe. Fishermen, factory workers, civil servants, pilots of cargo aircrafts, delegates of the European Commission, communities living around Lake Victoria: plenty of people are involved in some way in this new industry. But if Africa exports hundreds of tons of premium-priced fish each day, what exactly do Africans get in return?