North American river otters are likelythe most numerous of the otter species. Because theyare at the top of their food chain, they have few predators. However, waterpollution, uncontrolled trapping and severe habitat loss have reduced the number of river otters.
For years, river otters have been hunted for their fur, and theirpelts are still an important source of income for many people in Canada. As recently as the mid-1980s, more than 30,000 pelts were harvested annually. Today, accidental trappings in beaver traps constitute the most otter fatalities.
Regionally extinct throughout the Midwest and heavily populated areas in the east, several states have recently begun reintroduction programs. It is encouraging to note that with these conservation programs, regulations on trappingand the improvement of water quality, the river otters are finally making a comeback in certain wetland areas.
Because they have a low tolerance for polluted water, river otters are considered by some naturalists to be a good indicator, or "keystone," species of the quality of aquatic habitats. They are found at the top of the food chain, and there is some evidence that their birth rates are reduced when pollution levels—including toxic chemicals, heavy metals, pesticides and agricultural wastes—build up.
River otters have been blamed for decimating game fish populations and are seen as a pest to eradicate by many game fishermen. Recent research, however, indicates that otters prefer slower moving, easier to catch fish, such as suckers and catfish found along river bottoms, and pose no threat to game fish.
