All fish-eating predators, including otters, crocodiles, and humans, are threatened by mercury poisoning. Another threat comes from simple human activities such as the use of motorboats or motorized canoes. Otters are very sensitive to disturbance and will abandon their range with the advent of human settlement. Most human settlement in South America is concentrated along waterways, so otters have been seriously affected by human encroachment. Tourism Increased tourism is another potential problem for otters.
Tourism is both a blessing and a threat.
It brings money and attention to help conservation of otters. At the same time, unwitting tourists in motor boats can come too close to denning otters. If tourists are not careful, the stress of people invading their range can cause mother otters to stop producing milk and the cubs can starve to death. Conservationists believe this step had a tremendous effect on otter survival, and their numbers may be increasing. The remaining remote and pristine rivers, lakes, and wetlands of South America house a large variety of threatened and endangered species.