The largest body of fresh water in Africa, Lake Victoria, is in trouble, according to researchers. Among the threats to the lake's ecosystem (and the livelihood of many people) are exotic species introductions. The South America Water Hyacinth (Eichhornia crassipes) has become so invasive that populations were mechanically shredded several years ago in an attempt to prevent further spread. In addition, the introduction of non-native fish species as food sources has led to dramatic and unpredictable fluctuations in all fish populations, and also to government imposed bans on fishing. The combination of these threats with siltation and water pollution has led all involved parties to worry that a precious resource is in irreversible decline.