lake trout

The Environment Report
9:00 am
Thu December 12, 2013

Go lake trout! Native fish overcome seemingly ‘insurmountable’ challenges in Lake Huron

Ellen Marsden examines an egg trap on what is left of the historic spawning reef in Thunder Bay. This reef was buried in cement kiln dust which filled in the spaces between the stones where fish would otherwise deposit their eggs.
NOAA

A fish that was almost wiped out in the Great Lakes is making a comeback in Lake Huron.

Lake trout are suddenly doing what biologists have been trying to get them to do for more than 40 years: They’re making babies.

Lake trout used to be a mainstay of Great Lakes commercial fishing in the first half of the twentieth century. The Lakes would produce 15 million pounds of the fish every year.

Then the sea lamprey came in and sucked the life out of the lake trout populations.

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The Environment Report
9:00 am
Thu April 11, 2013

A surprising comeback for Lake Huron's native fish

Lake trout
Photo courtesy of Michigan Sea Grant

You can listen to today's Environment Report above.

For years now, we’ve heard bad news about the Great Lakes. Most of it has to do with invasive species getting into the lakes and wrecking the food web.

One writer called it a slow-moving underwater wildfire.

So it might surprise you to hear that native fish are doing very well in one of the lakes. The changes are so dramatic scientists are a bit puzzled and can’t explain what’s happening.

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Investigative
7:51 am
Tue August 23, 2011

Collapse of the salmon economy (Part 1)

Headed out to go salmon fishing on Lake Michigan near Grand Haven.
Lester Graham Michigan Radio

To understand why salmon are so important to the Great Lakes and the Michigan economy, you first have to understand some history.

It used to be the lake trout was the fish to catch.  It was big.  It was tasty.  But, by the late 1950s, that fish and others had been severely over-fished.  And, an eel-like, blood-sucking parasite called the sea lamprey further reduced lake trout numbers.

Those weren’t even the worst problems for lake trout.  A fish called the alewife invaded the Great Lakes through manmade canals.  Lake trout starting feeding on alewives.  But  alewives caused a thiamine deficiency in lake trout.  A lack of vitamin B-1.

Mark Gaden is with the Great Lakes Fishery Commission

“The thiamine deficiency that the alewives cause is one of the top reasons why natural reproduction has been very slow to occur over the decades in the Great Lakes of these species.”

Catching a lake trout became rare.

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Environment
11:29 am
Tue June 14, 2011

Lake trout on life support in Lake Michigan

Lake trout were once the big game fish in all of the Great Lakes. Some people still love catching and eating them.
Photo courtesy of Michigan Sea Grant

For twenty years now the federal government has been trying to restore wild lake trout in Lake Michigan. Lake trout are native to the Great Lakes and were once the big game fish in all the lakes. The species is doing well in Lakes Superior and Huron these days. But recovery efforts in Lake Michigan have been almost a total failure.

Lake trout don’t have a big fan club. Anglers would prefer to land a salmon. And retail markets for lake trout are weak.

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Environment
10:49 am
Thu May 5, 2011

Aircraft chemical found in Great Lakes fish

Researchers from Environment Canada found a chemical used in aircraft fluids in lake trout in the Great Lakes.
Photo courtesy of Michigan Sea Grant

New research finds that fish in the Great Lakes are contaminated with a chemical used in aircraft hydraulic fluids.

Researcher Amila DeSilva works for Environment Canada, which is like the EPA in the U.S.

She says there have been studies on a number of perflourinated chemicals. They’re used to make textiles, upholstery, paper, and many other things. Studies have shown these types of chemicals can have toxic effects in humans. But not much is known about a chemical called perfluoroethylcyclohexanesulfonate - or PFECHS for short.

DeSilva says no one has really studied whether it's toxic.

She wanted to see if PFECHS was in the environment, so she and her colleagues sampled water and fish in the Great Lakes, specifically lake trout and walleye:

“We were really, really surprised to find it in fish. Because, just based on the structure and our chemical intuition we thought, ‘okay, it would be more likely to be in water than in fish’ so when we found it in fish, when you find anything in fish, it’s a whole other ballgame because humans consume fish.”

DeSilva says other perflourinated acids are endocrine disruptors. That means they create hormone imbalances in humans, and they have other toxic effects. She says once these chemicals are released into the environment they don’t degrade, they just build up. That’s why use of some chemicals in this class is highly restricted in the U.S. and Canada.

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