They're weaned by 4 months of age, but often remain with their mother until the following spring. Young females can breed at one year of age, but many wait until they're two. Conservation Conserving wetlands and wooded areas along streams and rivers are top priorities. Reducing soil erosion and preventing fertilizers and pesticides from washing into streams are important measures, even where otters aren't likely to visit. For example, soil particles washed into a stream can settle when they reach slow-moving water, covering the rock, sand, or gravel that some fish need to lay their eggs and raise young.
Fewer fish means less food for otters.
Otters like to use dens and wetlands created by beavers. Protecting the long-term health of the beaver population is an investment in the river otter's future. Trapping is highly regulated in Illinois. Licensed trappers can harvest beavers only at certain times of the year and using only those methods allowed by law. This keeps beavers from becoming scarce while helping to control some of damage they can cause.