Commercial fishing and charter boat fishing are a large part of Wisconsin's economy. The industry is heavily dependent on the health of Lake Michigan and its fisheries. But they've been buffeted by invasive species over the past 70 years.
First by sea lamprey that entered the Great Lakes basin through the Erie Canal, which by the 1950s the lamprey had taken hold throughout the basin, decimating native fish species. Alewife was another. Those two “invasions,” along with overfishing, nearly wiped out native lake trout.
Salmon were introduced to try to create a new fishery and, as a bi-product, helped control the alewife.
In recent years, zebra mussels, and later quagga mussels, round goby and other non-native animals and plants arrived, causing additional upheaval in the food chain. Wisconsin Sea Grant fisheries specialist Titus Seilheimer says the ecology of Lake Michigan has changed.
Take the invasive round goby. With time, some Lake Michigan species realized they could eat the fish from Eurasia.
“It took a few years for the brown trout and the lake trout and the whitefish even, to recognize that this new fish, that’s very abundant is something that I can eat. And now [round goby] are an important food source,” Seilheimer says.
Another nonnative species called hemimysis, which are small shrimp, has also become a food source. “Very abundant in harbors, the break walls and potentially a food source for some of those smaller fish,” Seilheimer says.
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The biologist says brown trout and salmon are faring fairly well in Lake Michigan. “Those are species that we manage, we are stocking trout and salmon and kind of trying to balance the food web,” Seilheimer says.
Commercial fishers focus on whitefish and bloater chubs. “With the bloater chubs, the food just isn’t there for them and they’re kind of struggling,” Seilheimer says.
Lee Haasch owns a charter fishing business in Algoma. In his assessment, Lake Michigan's fisheries are doing pretty well.
“Like Titus eluded to, we're trying to harvest the fish that we’ve stocked in. We are seeing natural reproduction in the lake trout, we’re getting some in the salmon and we’re seeing some already in the steelhead. There’s not enough to sustain it by itself, so stocking will need to continue," Haasch says.
Haasch says his customers enjoy good catches on his boat. “They don’t necessarily see the behind the scenes that goes into managing this giant aquarium out here,” Haasch says.
Charlie Henriksen is a commercial fisherman based in Door County and chairs the Lake Michigan Commercial Fishing Board.
He says the decline in the bloater chub fishery has taken its toll. “We’ve lost a lot of members of our industry. For a long time chubs were the backbone. You could always go out there and make a buck. The whitefish industry has always been up and down. Those of us who are still in it are thriving but we’ve had some difficult times, there’s a very restrictive quota on commercial whitefish fishing in Green Bay, which is where the fish are,” Henriksen says.
Seilheimer worked with partners, including UW-Green Bay, to help guide the Wisconsin DNR as it recently increased the commercial fishing quota for lake whitefish from Lake Michigan.
Seilheimer says the previous plan was based on now out-of-date information from the 70s and 80s, detailing where whitefish were found in Lake Michigan at that time.
“We hired a graduate student who basically rode on the boats and counted the fish and helped collect data that could then help the decisions the DNR had to make about those quotas,” Seilheimer says.
The Wisconsin DNR sets up multi-year stocking plans. Its current 2020-2022 plan is meant to inform in 2023 and beyond.
Haasch thinks the plan works. “Nothing is ever perfect when you’re working with a diverse group of individuals. The best thing you do is you have to sit down and trust what data is available to you,” Haasch says.
Seilheimer adds that opinions vary. "Different stakeholders from different ports want different species, like 'I want to catch this, not that.' Sometimes lake trout might be looked as kind of this second class fishery, but then sometimes it's supporting a lot of people and historically had an importance to the commercial industry as well," he says.
Managers must balance what people want out of the lake and what the lake can support. And Seilheimer adds, coordinating fish hatchery output adds another layer of complexity. Yet, he sees promise in a project underway among his Sea Grant colleagues in Michigan.
“They’re modeling the populations of the different trout and salmon, the alewives, the prey fish and then allowing managers to tweak different scenarios and say ‘well if we stock this, then this is what we could expect’,” Seilheimer says.
That tool won’t be available for several years. And, of course, Lake Michigan does not belong to Wisconsin. Its waters and fisheries are shared by neighboring states and tribes, whose wishes must factor into the Great Lakes' management.
So, how can Wisconsin help manage Lake Michigan’s ecosystems for generations to come?
From Henriksen’s perspective, commercial operations and those producing food need to be part of the decision-making. “I'm sort of looking for a way as a personal mission is to involve some consumers in some of decisions because just like Lee’s business brings people to Algoma and they spend money, some go out and eat my fish and take his home,” Henriksen says.
Seilheimer believes future management will require bringing the best science to the table. “I see my role as helping to translate that science, not just to the stakeholders but even to the fisheries’ manager. I think the complexity of the food web in Lake Michigan is hard to keep track of,” Seilheimer says.
He says all stakeholders need to be at that table, “who are we missing in these conversations because these are public resources of the state and everybody should have a piece of those and be able to enjoy them, now and into the future.”
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