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Beaver Island bloody red shrimp research

Bloody red shrimp might be pests with a plus

Great Lakes invaders compete with fish for food but appear to be on menu, too

Contact: Heather Smith

At Central Michigan University's Biological Station and mesocosm facility on Beaver Island, biologists and students can conduct many kinds of research in a variety of conditions, all at the same time. This is one of three stories about current wildlife studies. The others concern lake whitefish, a struggling species; and island chipmunks, which are more than just cute faces.

"Bloody red shrimp" is a rather undistinguished nickname for an invasive pest that actually might be doing Great Lakes fish some good.

By being eaten.

They're not the kind of shrimp any human would enjoy on a cocktail plate ­— an adult is about the size of a large grain of rice — but early experiments by CMU faculty and staff show baby lake trout find them quite tasty.

The Great Lakes lake trout population has taken quite a hit over the past several decades because of overharvesting and various invasive species — including the shrimp — competing for the same food: animal and plant plankton.

But earlier this year in research at CMU's new Biosciences Building, baby lake trout feasted on the shrimp.  Biology students studying this summer at the CMU Biological Station on Beaver Island want to know if that trend holds in the wild.


Other struggling fish species might benefit, as well, according to Scott McNaught, a CMU biology professor leading the research.

However, there's also all that plankton the trout aren't getting, thanks to the bloody red shrimp.

"Is the net effect of the bloody red shrimp bad for the system or good?" McNaught asked. "We really don't know."

Mesocosm facility aids research

McNaught said Hemimysis — the shrimp's scientific name and a moniker the students often shorten to "hemmies" — originated in the Black Sea region and were first found in the Great Lakes in 2006.

The shrimp gather near the shoreline in water not exceeding 30 feet deep, and they prefer rocky shoals with their many hiding places over sand. They're nocturnal.

When the shrimp cluster, the water appears red.

Much of McNaught's summer research is conducted at CMU's new mesocosm facility, near the northern tip of Beaver Island. Its 12 tanks allow for tests that simulate natural condtions in a controlled manner.

At the facility, McNaught and his students use four tanks to study the effects of the shrimp and another invasive species, quagga mussels, on the plankton supply.

"We want to see if in combination with the quagga mussels the bloody red shrimp can have an even greater effect on plankton," McNaught said, "a kind of double hammer."

One tank of lake water holds only mussels, a second only shrimp, and a third has both. A control tank holds neither.

Everything's under control

On a recent summer day, Katie Grosh, of Ann Arbor, Michigan, an intern studying geology at Carleton College in Minnesota, was collecting zooplankton — microscopic animals — from the tanks. They were to be taken back to the CMUBS lab and counted. (Yes, counted. The lab has the technology to do that.)

There also must be precisely 25 bloody red shrimp and 900 quagga mussels in their tanks, Grosh said.

"We'll see from the very beginning to the very end of the experiment, Day 20, what happens to the number of zooplankton in the tank," she said. "Are the Hemimysis decimating the populations? Are the quagga mussels causing everything in the tanks to die?"

Grosh, a senior at Carleton, is a big fan of the mesocosm facility.

"It's so cool to have this whole setup right next to the lake," she said. "You're not going to get that anywhere else."

Emily Wimmer, a CMU biology graduate student from St. Clair, Michigan, is studying the shrimp as a potential food source for lake trout. She's at the Biosciences Building, putting the species together in large tanks.

So far, the trout are having a feast.

Wimmer said this level of research wouldn't be available to students at most other universities.

"I think the resources here to conduct research are beyond any other school in Michigan," she said. "I think the advisors and teachers have a very good relationship with their students.

"Students are excited and engaged to learn."

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