A rare North American river otter, whose population has been decimated by the fur trade and river pollution, was spotted in the Detroit River for the first time in a century, indicating improved water health. 

A North American river otter was spotted in the Detroit River by a local resident and marine ecologist studying at Windsor University in Ontario, which was later confirmed by officials to be the first sighting in 100 years. 

Eric Ste Marie lives on the Canadian side of the River, which divides Detroit, Michigan, from Windsor, Ontario. The river flows as a strait in the Great Lakes system. During a stroll along the river in late April, he saw a brown and furry animal in the water, mistaking it for a muskrat. But as the animal dove under water, Ste Marie discovered it didn’t have the flattened tail like a beaver, which “leaves otter as the only possibility,” he explained to CNN

Ste Marie confirmed with a biologist friend of his at the University of Windsor, and later with local experts and officials with grainy cell phone video footage, that it was indeed a North American river offer, which has not been seen in the Detroit River for a century. 

“I had a feeling it might be a rare encounter, but I really had no idea just how rare,” Ste Marie said. “It’s pretty crazy to be lucky enough to see one.”

River otters are semi-aquatic mammals that have thick, protective fur that keeps them warm in cold waters; long, narrow body and flattened head as well as a strong tail for streamlined movement. Historically, the species was found across North America, but their range has shrunk as a result of habitat loss from human urbanisation and development. Its population numbers – along with other species like beavers – have also dramatically declined since the 1600s due to the fur trade. 

Despite the end of the practice, the species failed to return to the Detroit River due to rampant river pollution in the Great Lakes and as the city of Detroit established itself as a auto industry leader in the country. Significant amounts of oil entering the river systems have huge impacts on river otters and beavers. When oil coats their fur, it prevents them to thermoregulate and keep warm, leading to death. 

But the Great Lakes have undergone major cleanup efforts over the past few decades. US President Joe Biden has also announced a USD$1 billion investment in February 2022 to restore the ecologically and biologically important water bodies. Together, this has paved the way for the return of the species. 

In 2019, river otters were observed at the Lake Erie National Park, which is next to Lake Erie. The recent reappearance of a keystone species at the Detroit River is another indicator that water health is improving. Though climate change, agricultural and urban runoff, as well as contaminated sediments remain to be threats to the species, the sighting offers renewed hope for more wildlife slowly moving back to the area, and overall health of the surrounding environment and waters. 

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