Students Net 1,000 Invasive Fish While Sailing Lake Michigan, and Nearly Nothing Else

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SUTTONS BAY, Mich. — Taking the helm of a 105-foot schooner on Lake Michigan, Brittany Amaral is sailing towards her future.

The master’s student in the U-M School for Environment and Sustainability (SEAS) worked on deck alongside fellow U-M students taking part in a hands-on experience through the University of Michigan Biological Station, the more than 10,000-acre research and teaching campus just south of the Mackinac Bridge in Pellston.

“I’ve never really been on a research vessel before, so being able to do science out in the seas especially on the Great Lakes since I go to school in Michigan but never really had the opportunity to visit one, it’s an amazing opportunity,” Amaral said.

The students drove from the northern tip of the Lower Peninsula south past Traverse City to board The Alliance — their classroom for the day — at its Suttons Bay port on Aug. 16.

They sailed for four hours as part of a UMBS course called Michigan Fishes in Changing Environments.

The research and education adventure is the capstone of the two-week extension course taught at UMBS by Drs. Karen Alofs and Hernán López-Fernández.

“This course is the field extension for Biology of Fishes, which is offered in the fall semester in Ann Arbor taught by Dr. López-Fernández, and Ecology of Fishes, which I teach in the winter semester down on main campus,” said Alofs, an assistant professor of ecosystem science and management in SEAS. “Students who have taken or plan to take either of those courses can then register for this course at UMBS and join us out here.”

When Meredith Dirkman considered applying for the field extension course in northern Michigan, the Lake Michigan sail was what hooked her.

“This was a huge research schooner you get to go on, and you get to experience something I’ve totally never experienced before,” said Dirkman, a senior at U-M who studies ecology, evolutionary biology and the environment. “There’s a lot of other parts of the course — there’s field work, there’s tissue sampling, all of these collection techniques, but I honestly was excited about going on the boat.”

Before heading out on this excursion, the class worked in creeks and inland lakes like Douglas Lake, where the UMBS field station is nestled. The students found a common snapping turtle — Chelydra serpentina — on Douglas Lake using a fyke net during their first week. They also saw plenty of invasive zebra mussels.

Aboard the ship, the students conducted water quality sampling in Lake Michigan such as using a Secchi disk attached to a rope to gauge clarity. The crew recorded how far below the surface the disk disappeared from view.

The students used a microscope to identify plankton gathered from the water column.

But the most eye-opening work involved invasive fish called round gobies, learning first-hand how the it has grown dominant in the Great Lakes.

“It’s very different to read about something and rationalize it, and to actually be there in person for a few hours and see how significant it is,” said López-Fernández.

The students worked in teams to lower and raise an 18-foot net that is towed up to 30-feet deep.

“We’re setting an otter trawl off the Inland Seas,” Alofs said. “We’re dragging it along the benthic surface, the bottom of the bay, for 10 minutes at a time and then getting the fish out of that trawl and seeing what we caught.”

The students were shocked by the lack of fish diversity, netting 1,047 invasive round gobies and almost nothing else — four young smallmouth bass, one rock bass and three brook stickleback.

“It’s interesting and depressing to see how the round goby invasion actually plays out in real life,” Dirkman said.

Round gobies are changing the food web in the Great Lakes.

“The sheer number represents an enormous amount of competition for other species,” he said. “As egg predators, they will prey upon the eggs of native fishes, raiding the nests of bass, for example.”

It also appears lake trout are shifting their diet increasingly toward goby.

“That means they are feeding on a better source of certain vitamins, as opposed to alewife, which is a poor nutritional source,” López-Fernández said. “That is resulting in an unexpected improvement in the nutrition of native lake trout.”

“It’s cool to be able to see on a larger scale how these fish I’ve been seeing in the streams are living in a bigger body of water,” Amaral said.

The day offers a meaningful tension to ensure the next generation of scientists and environmental stewards is ready to take the wheel and protect freshwater resources amid a diminishing ecosystem.

"Balancing that beauty and amazement and joy of being out here with that the fact that we’re catching fewer species of fish than we’ve caught anywhere else is something to think about — the impacts of invasive species," Alofs said.