Thomas Hrabik has spent a lot of time in the last three decades out on Lake Superior studying the fish.
“I don't even remember how many research cruises are under my belt,” said Hrabik.
The University of Minnesota-Duluth Biology Professor studied all manner of fish in the largest of the Great Lakes.
Some of his favorites are the ones you find in great depths, like Kiyi.
“They're the deepest water white fish in the lake, or Cisco species in the lake,” said Hrabik. “They were just fascinating to me because they have a huge eye relative to the size of their head. Their fins are really large in proportion to their body size. They're just really unique.”
Hrabik calls them the epitome of Lake Superior because of how well they’ve adapted to the deep, dark, cold conditions of the lake.
They’re so adapted to those conditions, that they actively seek them out, going to deeper depths during the day to avoid any light.
“They move vertically daily. These fish are moving 600, 700 feet in the span of an hour to come up at night to, let's say, 60 to 80 feet deep,” said Hrabik. “They feed for a few hours, and then right before dawn, they start to go back down. Part of my early career was establishing that behavior.”
Hrabik is fascinated by the fish of Lake Superior, but he’s also concerned for them and other cold-water species.
Lake Superior is one of the fastest warming lakes in the world. Ice cover has been decreasing significantly over the years.
These changes will make it harder for species that need that cold and ice to survive.
“As that changes, then the species that are more adapted to warmer conditions are going to do much better, and probably displace some of the native cold water fish,” said Hrabik. “I think that message is one that I would just present as a warning for what's likely to come if the conditions continue to change.”
It’s one of the main messages Hrabik hopes people will take away from his upcoming Science on Tap Minocqua talk.
He’ll be talking about Lake Superior fish this Thursday, January 2nd at Rocky Reef Brewing Company in Woodruff.
It’s starts at 6:30 p.m. and can also be streamed online.
