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Sturgeon remain rare in Great Lakes, but Detroit River's population thrives

Carol Thompson, The Detroit News on

Published in Science & Technology News

THE DETROIT RIVER — A pair of federal fish experts braced themselves as they cradled a hulking fish over the side of their boat just north of the Grosse Ile Toll Bridge. Its kick would be strong enough to unhorse a novice angler, but the duo had performed this routine 31 times in a handful of weeks and were on pace to do it maybe a hundred more before the season's end.

Still, it felt like a lucky catch. The U.S. Fish and Wildlife Service's Gibraltar-based lake sturgeon team had been out all day without finding much more than a mudpuppy. It was early May, and by then, the water had reached above 50 degrees, warm enough that their targets were less likely to feed on the bits of round goby serving as bait.

But finally, after pulling hundreds of empty hooks out of the Detroit River, they caught one. Into the tank he went, all 70 pounds and 5-plus feet of him, a fish that had sustained multiple sea lamprey bites and probably spent his near-50 years meandering the waterways that connect lakes Huron and Erie.

He's far from alone.

Throughout the Great Lakes, lake sturgeon populations have been decimated to approximately 1% of their historic numbers, but that's not the story in the Detroit and St. Clair rivers. Here, the species holds strong at about 30,000 fish. The rivers boast the most resilient lake sturgeon population in the Great Lakes basin.

That's despite the legacy of industrialization that still impairs the two waterways. The Detroit and St. Clair rivers were contaminated by decades of sewage overflows, coal burning and industrial ooze. Their shorelines were hardened, lined with seawalls and factories. They are major thoroughfares for shipments of coal, salt and iron ore.

 

Those actions swept away fish spawning habitat and damaged ecosystems. Still, the rivers' robust lake sturgeon numbers have become central to endeavors to rehabilitate the species throughout the Great Lakes.

"I've been working here for 14 years now, and people think 'the Detroit River? There's no fish there. Why are sturgeon there?'" said Justin Chiotti, fish biologist for the Fish & Wildlife Service's Alpena conservation office's Detroit River Fish Laboratory in Gibraltar. "But they don't see the thousands of people that are out here walleye fishing every day, don't see that this is home to the largest lake sturgeon population in the Great Lakes."

The Gibraltar-based lake sturgeon team sets 700-foot lines targeting lake sturgeon throughout the Detroit River and checks them at least weekly through April and May. Some are set alongside natural areas, such as Fighting Island. Others are within clear sight of steel mills, factories and chemical waste sites.

When they hook a sturgeon, the biologists pull it on board to collect data on its size, sex, age, injuries to help them understand more about the population's size, growth and trajectory. They also install tags used to monitor where the fish moves during its life, which likely will last longer than a biologist's career. Then, they return the fish to the water.

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