alewives

R/V Laurentian NOAA / Creative Commons

You’ve probably heard about the big bad invasive silver or bighead carp, also known as Asian carp.

But there’s another invasive fish that’s roughly a third the size of the carp that’s already done a lot of damage to Great Lakes fisheries. Alewives have been a particular menace in Lakes Michigan and Huron. The invasive fish cause all kinds of problems for native lake trout.

Alewives scarf down lake trout eggs and very young fish. But even once lake trout grow big enough to turn the tables and eat the alewives, the invasive fish still cause problems.

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.

Lester Graham / Michigan Radio

It looks like food for salmon will continue to be scarce in Lake Michigan. Researchers say it appears not many alewives were born in the lake this year - and salmon eat almost nothing else.

Neither salmon nor alewives are native to the Great Lakes, but it's bad news for people trying to keep the billion-dollar sport fishery alive in Lake Michigan.

Peter Payette is with our partners at Interlochen Public Radio and he's been covering this story. He explains that every year researchers go out on the lakes to see what’s happening.

"One of the important surveys is of prey fish, the little feeder fish that big fish like salmon like to eat, and in Lake Michigan this year they found very few newborn alewives. There are alewives in the lake, ones that were born in years past. But the young of the year, the new class of alewives; they found very few," he says.