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'Fish vampires' attaching to trout in the Great Lakes

Posted at 9:42 AM, Dec 02, 2019
and last updated 2019-12-02 09:42:25-05

EAST LANSING, Mich. — A 12-year project at Michigan State University has set out to learn just how invasive species affect the Great Lakes and its trout population.

It took multiple graduate students years to see how sea lamprey, also known as Vampire Fish, affect the ecosystem.

The lamprey, which are an invasive species, use sharp teeth to latch onto fish and suck their blood.

At MSU, they've been studying the affects the lamprey have on trout in the Great Lakes. Student Tyler Firkus housed some trout at a lab in Wisconsin, and throughout the project, he let the lamprey attach to the fish for four days or less.

Any longer than that, and they would die.

"We know that most of them will die when they are being attacked by a sea lamprey, but do the ones that survive still act like normal individuals in the population?" said Firkus.

Firkus worked with his PH-D advisor, Cheryl Murphy to answer that question.

"Yeah it requires a certain type of pioneering mindset I think," said Murphy, an associate professor of fisheries and wildlife. "And then you have really good people that work on it like Tyler, and it's just a challenging project but its been really great to see it and we're getting really good results along the way."

Those results can be seen under a microscope; sperm cells that are counted multiple times over.

Firkus found that trout that do survive the lamprey attacks, have fewer sperm cells, making it difficult for the species to reproduce.

"There is clear visual difference in the number of sperm cells in those samples, so you can see that the sperm reduction is reduced in those fish that were parasitized," said Firkus. "Being in the Great Lakes state, the health and ecosystem of the Great Lakes is really important for most of us. So understanding the effects of some of these invasive species is really important and something people should be aware (of)."

It has taken intense programs from the Department of Natural Resources and the Great Lakes Fishery Commission to restock trout populations during the peak of the lamprey attacks back in the 1960s. And this research at MSU proves programs like that have kept trout alive and swimming in the Great Lakes.

"If we continue managing and continue working on this problem, hopefully we can continue to see the recovering of these lake trout in the Great Lakes," said Firkus.

This study was 100% funded by the Great Lakes Fishery Commission.