Otter released into the Utah River

27/11/2009 23:27:33 Release launches Utah's third confirmed otter population
November 2009. Biologists with the UTAH Division of Wildlife Resources (DWR) have released a northern river otter into the Provo River.

The otter, a young adult female, is the first of 10 to 15 otters the DWR hopes to place into the Provo River in the next few months. The otter was trapped by DWR biologists on the Green River in north-eastern Utah.

Three-year study
Releasing river otters into the Provo River will provide Utah with another river otter population. It will also provide biologists with valuable information about the habits of river otters in the state.

"Releasing this otter marks the beginning of a three-year study to learn more about otters in Utah," says Justin Dolling, game mammals coordinator for the DWR.

The day before the otter was released, a veterinarian at Brigham Young University placed a small transmitter in the otter's abdomen, just under its skin. The transmitter will allow Casey Day to track the otter. Transmitters will also be placed in other otters that are released into the river.

"The types of food otters eat, the distances they travel and how successful they are at reproducing are among the things Day will learn," Dolling says. "The information we gain from his study will guide us in other river otter reintroductions we do in the future."

Otters and trout
DWR biologists have heard from anglers who are concerned about the effect river otters will have on trout in the middle Provo River.

"Crayfish are an otter's favourite food," Dolling says. "But if they can't find crayfish, they'll turn to other sources, including frogs and fish. An adult otter eats about two to three pounds of food per day."

Dolling says the Provo River has plenty of crayfish. But if the otters have any difficulty finding crayfish in the river, there are plenty of fish to eat. "Otters usually target slower-moving fish, such as sculpin, whitefish, carp and suckers," he says. "Most of the fish they eat are between five and seven inches long."

Dolling says the river otters will also eat trout. And that may not be a bad thing.

Walt Donaldson, Aquatic Section chief for the DWR, says the middle Provo River is a blue ribbon fishery that's known to anglers across the country. "We reintroduced otters into the Green River in 1989, and they've haven't caused the fish in the river any problems," he says. "After otters are placed in the Provo River, we'll keep monitoring the fish population in the river. If we find the otters are causing the fish problems, we can take management actions to make sure fishing in the river doesn't suffer."

Those actions include stocking trout in the river and capturing and removing some of the otters.

Otters in Utah
River otters were never abundant in Utah. But they were found in various parts of the state. Some of the biggest populations were in northern Utah. River otters were doing fine until Utah was settled, then over trapping started to take a toll. In 1899, the Utah Legislature closed the state to otter trapping.

Otters faced another challenge, though: the degradation of vegetation along steam banks, and agricultural and urban encroachment. Each of these factors affected water levels and water quality in the state. And that, in turn, that affected the otters' food supply. As their habitat and food supply declined, the number of otters declined too.

Bringing otters back
Management practices during the 1900s improved conditions along some of the state's steam banks. That, in turn, improved water quality. By the 1980s, it was time to increase the number of river otters in Utah. The DWR started expanding river otter populations in 1989 when biologists released nine otters from Nevada and Alaska into the Green River in north-eastern Utah. The DWR followed the 1989 release with several more otter releases in the area.
In 2005, Utah's river otter population expanded more when three otters trapped by the DWR in north-eastern Utah were released into the Escalante River in south-western Utah. That release was also followed by several other releases in the river.