River otters were historically in Ohio but were extirpated by the early 1900s. The Ohio Division of Wildlife started a seven-year reintroduction program for river otters in 1986. There were 123 otters released on the eastern side of the state. Today, the otter population is estimated to be over 6,500. As the population increases more problems are likely to occur with this species.
Otters have been known to cause damage in private ponds and fish hatcheries. Aquaculture operations and koi ponds are sometimes a target for river otters as the food sources are plentiful. If you notice uneaten fish heads with the skeleton attached along with scat piles, you more than likely are dealing with a river otter in your pond. Their scat piles will consist of scales, exoskeletons and sometimes body parts of fish. River otters will not live in a pond, but rather in a creek or river that is located close to a pond. Often they will travel to find a food source stumbling across a pond. They will repeatedly use the same spot along a creek or river bank to urinate and defecate. These locations are called latrine sites and help you identify if an otter is denning close to your property. Otters are capable of consuming 2-3 pounds of fish per day. When observing damage to a pond, keep in mind that blue herons are also a culprit of killing stocked fish. Herons will leave behind uneaten carcasses with large puncture holes. Mistakenly, river otters get blamed for the damage because they were spotted in the vicinity.
Fencing is a way to keep otters out of ponds by using a 3-inch wire mesh at around 3-4 feet tall. By burying the fencing into the ground at 6 inches, this will prevent the otter from pushing underneath the fence. Providing structures such as Christmas trees or cinder blocks for fish will give them safe places to hide from predators such as otters. There is a trapping season on river otters which runs from the end of December through the end of February in specific counties throughout Ohio. You can refer to the Hunting and Trapping Regulations for additional information. If issues are occurring outside of the trapping season, river otters can be live-trapped and relocated with permission of the landowner where the otter will be released. You may contact your local district office or county wildlife officer for further assistant if lethal control is needed because of certain conditions.