Notes from Minnesota: Return of the River Otter

After 35 years, river otters are becoming plentiful in the Cedar River once again. Photo: Joe Frisk

On a frigid February afternoon, I walked the path around the Mill Pond in downtown Austin, Minnesota. A recreational area with a bike path, skate park, and swimming pool, the Mill Pond was formed by damming the Cedar River in the early years of the city.

As I crossed a bridge spanning the river, movement out on the ice caught my attention. For a moment, it looked like a sheet of black tar paper, waving in a non-existent breeze, but a closer look revealed an otter! A big guy, he was greedily devouring a fish.

I pulled out my camera and began to shoot video as a second otter appeared from under the ice. This was the first pair I’d seen since those I’d observed in Austin’s Sutton Park back in the mid 1970s. After 35 years, the river otters had returned.

The River Otter

Weighing 18-30 pounds, otters are powerful and sleek swimmers. Photo: Joe Frisk

The river otter is a member of the mustelid family, a group that includes mink and weasels, and is partly aquatic. Its streamlined build and semi-webbed paws help it hunt fish. In fact, an otter can match a trout in maneuverability. Northern river otters can reach — and even exceed — 30 pounds and five feet in length, with males being larger than females. Otters were once the most widely distributed mammal in North America and Canada, but pollution, habitat loss, and unregulated trapping resulted in huge population declines.

In southern Minnesota, water pollution and loss of wetlands took a heavy toll on the otters, and they all but disappeared. In spite of spending countless hours fishing, trapping and bow-hunting along the Cedar River, I saw no otters. Yet, healthy populations remained, hiding out in more remote regions, such as the swamps of Louisiana and the lake country of northern Minnesota. These regions would provide the seed animals for restocking efforts.

Reintroductions

Pollution threatens the well-being of acquatic wildlife, such as otters. Photo: © RbbrDckyBK - Fotolia.com

The loss of wildlife and habitat helped spur action in Minnesota and around the country. Wetland restoration efforts ensued and the Clean Water Act of 1972 began to improve our watersheds.2 Strict laws on farm and industrial pollution took effect, benefitting our water and preparing the way for the reintroduction of otters.

According to Dr. John Erb, wildlife biologist with the Minnesota DNR, about 20 otters from northern regions of Minnesota were released on the far upper reaches of the Minnesota River. Otters did not have to be reintroduced in extreme S.E. Minnesota, as natural re-colonization has occurred along the Mississippi River and many of its tributaries.

Dr. Erb conducted a study of this population from 2001-2003, implanting some otters with radio transmitters. He found most females were going up into the bluffs to have their litters, likely in order to avoid losing their young to drowning during floods. The downside is that some females were killed trying to cross the highway to and from the Mississippi.

In Iowa, a total of 325 otters were brought in from Louisiana, beginning in 1985, and released at 25 sites throughout the state. In spite of straight-pipe pollution and heavy runoff of hog manure, the otter population has been increasing by 7% per year. Statewide, numbers are now estimated at 6,000 to 8,000 animals. With equal or better water quality in Minnesota, it’s likely some of the Iowa releases have made their home here and will be on the increase.

In 1989 and 1990, a total of 23 otters, 12 males and 11 females, were released along the Cedar River by the Iowa DNR. The release occurred about 14 miles south of Austin near Otranto, Iowa. They also released a dozen otters into the Shellrock River, a tributary of the Cedar. I believe the otters I saw at the Mill Pond came from the Otranto releases, as they love to roam and can easily cover 25 miles in a week.

The Eagle and the Otters

Around four years ago, an amateur photographer went to check on an eagle’s nest three miles south of Austin. He left his camera at home, believing he would not see much. It proved costly, as he feels he missed the shot of a lifetime. Walking back to his car, he noticed an eagle perched in a tree near the roadway and staring intently at something along the riverbank. Peering over the side of the bridge, to see what the eagle was eyeing, he spotted a family of five otters eating a carp. The eagle was trying to figure out a way to steal the carp.

This incident showed that otters were here by the middle of this decade, but most of us did not see them. The gentleman returned, many times, and never again saw the otters. In an email, Jaime Edwards, a wildlife specialist with the Minnesota DNR, commented, “Most of the time you see signs, but not the critters!”

A DNR Survey

The city of Austin can be seen at the top of this map courtesy Dr. John Erb, MN DNR. Otter sign is indicated by the red dots, showing the otters had made it upriver from the Iowa border (dark line near bottom of map) to the city by 2001. Map: Courtesy of Minnesota DNR

Donna Kolb lives near the Cedar River in Austin and has observed adult otters for around six years, watching them play in her yard and in a park. When she first saw them, she called police, not knowing what they were and worrying they might attack children. Fortunately, the police, also unsure of what they were, left them alone.

Kolb’s sightings are backed by the findings of Dr. Erb. He mapped otter signs for a survey he conducted along the Cedar River in the winter of 2001. Dr. Erb and his team searched by helicopter for otter slides and tracks in the snow along the riverbanks, starting ten miles north of Austin and continuing to the Iowa border.

Otters love to play and slide down muddy or snowy banks leaving telltale markings behind. No sign of them was found north of Austin, but signs turned up right in town and south on the Cedar, evidence the Iowa otters had moved upstream.

My sighting also corroborates their presence in Austin and that of amateur naturalist Bernie Anderson puts them north of town. In late fall of 2009, Bernie observed a pair of adults three-quarters of a mile north of the Interstate 90 bridge, just north of Austin. One had caught a frog and Bernie also found evidence they had been feeding on freshwater mussels.

Larry Dolphin, Director of Austin’s J.C. Hormel Nature Center, has received several reports of otters in the area. In the spring of 2001, there were otters on Rose Creek just east of Austin. A year ago, otters were spotted on Wolf Creek to the northeast of the city. Dolphin believes the otters in our area most likely came from the Iowa stockings, being well within their normal range of travel.

A Bright Future?

If we protect the rivers from pollution, we'll see more and more river otters returning to our waters. Photo: © Janice Barchat - Fotolia.com

With no trapping season in this part of Minnesota, and with continued improvements in water quality, I believe the future of these curious and playful animals is bright. Otters are still being accidentally trapped and some have been hit by cars, but they have few natural predators in southern Minnesota. Coyotes are the main predatory threat here.

Pollution is still a problem, with farm runoff raising nitrate levels and muddying the rivers. High nitrate and silt levels lower water quality and decrease the likelihood of otter survival. Otters need clean water. So far, they seem able to shrug it off, but pollution must continue to be addressed by farming and other industries. Industry will often pollute if they believe they can get away with it. This has to stop if we want otters to stay around.

All of us who care about our water should keep an eye open and report incidences of abuse. We can make a difference. Cleaning up the river here in Minnesota benefits all communities along the entire 329 miles of the river.

The return of the otters to the Cedar River was an event I was fortunate to observe and record. With continued work and perseverance, otter sightings could well become a more frequent pleasure, here and around the nation. We have to put an end to using our rivers as open sewer systems. We owe it to all who have helped to restore our waterways and wildlife.

Joe Frisk

Contributing Writer

Blue Planet Green Living (Home Page)

For More Information

Grandfather Mountain

River Otter Resurgence in the Upper Mississippi River Watershed

William Clark, “Wildlife Population Dynamics- River Otter Landscape Ecology” Iowa State University

Iowa DNR Wildlife

Susannah J. Bedford

Minnesota DNR

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