Bracing for Climate Impacts on Lake Erie, the Walleye Capital of the World

Peg Van Vleet began fishing on Lake Erie when she was just 5 years old. A charter boat captain for more than two decades, and also the vice president for environmental issues for the Lake Erie Charter Boat Association, she’s looking forward to a great fishing season this year in its western basin.

“The young fish are growing very fast, which tells us that there’s a lot of good plankton in the water for these young fish to eat and get big,” she says.

Yet while Lake Erie’s fisheries are thriving now, climate change will present challenges down the road—even if the most recent survey of licensed charter boat captains doesn’t spell it out in so many words. 

Climate change wasn’t listed as a separate issue in the Ohio Sea Grant’s survey, said Tory Gabriel, the grant’s extension program leader and a fisheries educator at Ohio State University, during an April briefing on the most recent survey results. And in a 2010 survey, captains didn’t rank climate change as a priority compared to other issues. But in that survey and in 2020 they did express concerns about issues linked to climate change, including harmful algal blooms, the lake’s dead zone and water levels.

Revenue for Ohio’s Lake Erie charter industry increased roughly 50 percent from 2010 to 2020, for a total of about $14.6 million in 2020, the first year of the Covid-19 pandemic, according to the Ohio Sea Grant survey. 

“We have about a $1 billion sport fishing industry in Ohio,” Gabriel said. That figure includes estimated economic activity supplying the industry, tourist businesses in areas supported by sport fishing and various economic multipliers.

“Lake Erie is widely regarded as the walleye capital of the world because of our spectacular sport fishing opportunities,” said Travis Hartman, Lake Erie fisheries program administrator for the Ohio Department of Natural Resources’ division of wildlife. Roughly 88 percent of trips targeted walleye during the 2020 season, followed by yellow perch, the survey results show. 

The lake’s western basin is most popular for sport fishing, but many people also fish in the deeper central and eastern basins. Fish migrate from basin to basin.

Smallmouth and largemouth bass are also popular for sport fishing, Hartman said. And harbor areas provide seasonal catches for panfish, such as bluegill, crappie and rock bass.

Modeling by biologist Stuart Ludsin at Ohio State University and others predicted Lake Erie’s current healthy fish populations. But that will change in the coming decades.

“Continuing warming on the trajectory we’re going is not going to be good for walleye and yellow perch,” Ludsin said. 

Climate models forecast that the fall, winter and spring seasons will generally be wetter, while summers will generally be drier and hot, said Chris Winslow, who heads Ohio Sea Grant and Ohio State University’s Stone Laboratory. 

“We’re anticipating not only warmer air temperatures, but also elevated lake temperatures,” Winslow said. In many places the water will actually warm more. So, if the air temperature rises 2.5 degrees Celsius, the water might be as much as 4.2 degrees Celsius warmer, he said. 

Figuring out all the impacts is challenging because the lake is a dynamic system. “It’s sort of a researcher’s dream and a manager’s nightmare, because it’s constantly changing,” said Ludsin.

Milder Winters, Extreme Events

Less ice cover in winter is generally linked to lower levels of recruitment—or fish surviving long enough to grow large. In years with harsh winters, cool and cold water fishes tend to lay fewer eggs than when winters are mild, but the eggs are generally larger, Winslow explained. So, “that fish has a little bit of safety yolk fat to last a little longer.” 

Warmer Winters Strain Fish Survival

Wetter weather will also increase runoff into river systems that feed into the lake, he said. That will likely increase levels of microplastics, which pharmaceuticals, caffeine, nicotine and chemicals glom onto. Those could affect fish health.

More runoff could also flush more fertilizer into the lake. Ecosystems in the lake need some nutrients, but too many increase the likelihood for more severe harmful algae blooms in the summer. 

Those blooms disrupt the balance of phytoplankton in the food web. Some strains of microcystin, the cyanobacteria that causes most blooms at the western end of Lake Erie, are also toxic. And, as the algae die and sink to the bottom of the lake, other bacteria feed on them, consuming oxygen in the process, which leads to areas holding little or no oxygen to support other life.

Lower parts of the lake are generally cooler than the upper water. But warming of the lake, especially in the western basin, could lead its sediments to release more phosphorus, another source of nutrition for harmful algae blooms, research by Kenneth Gibbons and Thomas Bridgeman found.

On the other hand, some research has shown that predator fish tend to eat more in areas outside of river plumes with extra nutrients, Ludsin noted. The extra turbidity in the plumes could help young fish that otherwise face predation by making them harder for visual predators to see.  

Yet harmful algal blooms don’t only affect fishes. Bad blooms have led to drinking water advisories, swimming bans and other problems. So, some management efforts are necessary to control the blooms. 

“If you start implementing conservation practices to clean up Lake Erie and harmful algal blooms and hypoxia, there’s tradeoffs associated with that,” Ludsin said. He and colleagues described the forecasted results for different scenarios in the journal Freshwater Biology in 2020. The team didn’t pick an optimal solution, but expects the analysis could help fishery managers plan as the climate continues to change.

Climate change won’t just bring warmer temperatures and more precipitation. “Extreme weather events have been changing,” said Josef Ackerman, who studies ecology and aquatic systems at the University of Guelph. 

Research by his group found that, from 1980 to 2018, water temperature and wave power increased during the month of August. At times when extreme winds blow toward the west, they can alter the usual flow of water in the lake. 

That can move “a shipload of water” from the central basin toward the west, Ackerman said. Flows would shift as the water meets Point Pelee, he added. Then there’s an upwelling of water from colder, low-oxygen zones. If fish or other organisms can’t swim out of the way, they could suffer. 

Water “flipping over” can happen naturally as weather events shift hypoxic waters in different parts of the lake, said charter boat captain Van Vleet. Those events explain dead fish washing up on shores in late winter and early spring. “That’s pretty normal this time of year,” she said.

But Ackerman’s group focused on data for August. And the team’s historical analysis found an increase in hypoxic events in the western basin over the past four decades, with 21 of 49 events happening in the most recent decade. Many fish can swim to escape oxygen-depleted areas, but not always.

Fluctuations in water levels also can cause problems for near-shore habitats. And extreme weather can increase coastal erosion.

“What happens to our shoreline when those eight- to ten-foot waves come crashing on our shore?” said Van Vleet. “And what are we going to do to structurally enhance and protect our shoreline?”

In the meantime, Van Vleet and other charter boat captains hope more people will get out on the lake. “I do this to share my love for the lake and the fisheries with people who don’t have an opportunity to get on the lake as frequently as I do,” she said. “If I can hook one kid a year on fishing, that’s one less kid a year that’s on the streets.”

Creating a new generation of fishers may also create a conservation mindset, Gabriel said. 

“Anything you can do to get people out and around Lake Erie will help people in the long term understand its importance,” he said.

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