Jeff Butzow’s display cases at Fish Lads in the downtown market in Grand Rapids, Michigan are filled with about 40 varieties of fresh and wild-caught fish from all around the country: halibut from Alaska; black cod from Washington State; salmon from the Pacific Northwest. He even has some perch, whitefish, and walleye from the Great Lakes region.

But when talk turns to commercial “net-pen” fish farms in the nearby Great Lakes, Butzow, who has been in the fish business for nearly two decades, bristles. “There’s already enough pollution in the Great Lakes, why make it worse?” he asks.

And he’s not alone. Michigan is in the midst of a contentious debate over whether the Great Lakes surrounding it should be opened up to this type of commercial fish farming, which involves setting up pens offshore that could raise both native species like whitefish and non-native species such as trout and salmon. Until now, only a limited number of net-pens have been allowed off the coast of Ontario, where the industry produces 10 million pounds of trout annually.

In 2014, developers proposed two concepts for commercial rainbow trout operations in northern Lake Michigan and northern Lake Huron. One of the companies, Coldwater Fisheries of Ontario, has operated in Lake Huron since 1987 and has said its Lake Michigan project could harvest up to 3.5 million pounds of fish a year. That interest led a trio of Michigan state agencies to study the feasibility, regulations, and legal restrictions of net-pen aquaculture in the Great Lakes. Since then, the debate among interest groups has grown steadily.

Residents like Butzow say net-pen aquaculture is too risky for the environment and native species and should therefore be banned. Supporters from the commercial fishing industry and some legislators believe that with the right regulations, it could be done in a way that bolsters the state’s lagging aquaculture industry, which a 2014 Michigan Sea Grant strategic plan calls “underdeveloped” at merely $5 million in sales a year. The Sea Grant report also notes that the United States’ seafood deficit exceeds $12 billion and grows by roughly $1 billion a year.

While the demand for seafood is on the rise, and many in Michigan would like to see their state import less from overseas, there are big questions about whether the consequences would outweigh what opponents say would be relatively small industry growth. According to that 2014 strategic plan, whose principal investigator is a researcher at Michigan State University, global seafood demand is expected to increase by 100 billion to 170 billion pounds and $330 billion by 2030.

“With 20 percent of the world’s usable fresh water along its borders, and freshwater aquaculture supplying over 60 percent of global production, many believe strongly that Michigan is capable of creating a billion dollar sustainable seafood sector by 2025,” the report authors note.

According to the National Oceanic and Atmospheric Administration (NOAA), about half of the seafood eaten worldwide is farm-raised, but most of what Americans eat comes from outside the U.S. Supporters argue that opening vast freshwater areas for fish farming in the Great Lakes would not only expand the quantity of seafood raised state-side, but also help it compete with marine coastal areas and boost the sales of species native to rivers, lakes, and streams.

However, experts say Great Lakes pen aquaculture is not similar to ocean environments, where nutrients from fish waste are more freely and broadly circulated. This concentration of fish waste in Great Lakes pens is the chief concern among environmental groups because fish waste contains phosphorus. Excessive levels of the nutrient can damage the ecosystem, which has been the case in Lake Erie on a much larger scale and the reason the state is trying to control phosphorus inputs to the lakes, particularly from the agriculture sector. Environmental groups say there are inland alternatives, such as using warehouse space to raise many popular species indoors.

“When I look at aquaculture operations, [state agencies] should do their due diligence about creating an operation that’s economically viable and still environmentally responsible,” said Gef Flimlin, a marine extension agent at Rutgers University and president of the U.S. Aquaculture Society.

Michigan at the Center of the Debate

Michigan’s more than 3,000 miles of freshwater shoreline has placed it at the center of the debate around Great Lakes net-pen aquaculture—and perhaps rightly so. State law requires all aquaculture facilities to be in privately controlled waters, which the state has interpreted to mean not allowed in the Michigan portion of the Great Lakes.

Lawmakers in both political parties and both chambers of the state Legislature have proposed banning the practice or allowing it to expand.

The group of state agencies (comprised of the Michigan Department of Agriculture and Rural Development, Department of Environmental Quality, and Department of Natural Resources) issued its final review in March, recommending against the practice. One DNR adviser told the Associated Press that the agencies were in “lockstep” against it because of the potentially negative impacts on the lakes and wild fish populations; the relatively little potential for economic growth; the millions of dollars in oversight costs it would require; and the overwhelming majority of public input the group received against it.

The Michigan Environmental Council (MEC) was encouraged by the report.

“Based on the science currently available and looking forward at the technology available, there is no way to do this safely in the Great Lakes without putting the lakes and tourist destinations at risk,” said Sean Hammond, the MEC’s deputy policy director.

Of the limited number of sites in Ontario, Hammond said areas of Lake Huron around the pens in the late 1990s saw “extraordinarily high phosphorus levels and anoxic conditions.”

But Chris Weeks, an extension specialist at Michigan State University who was an author of the strategic plan report, said Ontario has a regulatory framework in place to “rectify the situation” if facilities don’t meet the requirements.

“If we have 20 percent of usable freshwater in the world and 60 percent of aquaculture is from freshwater systems, then obviously the [development] potential is very high” in the Great Lakes Weeks said.

He also believes there is demand for more affordable local seafood. “One of the things that interests me quite a bit is [the idea] that you could go to Meijer or Kroger and see a good product that’s $6.99 from Ontario waters,” Weeks said. “That should be on the table.”

Can Land-Based Aquaculture Thrive?

Hammond’s group does, however, “fully support land-based, responsibly done aquaculture.” In particular, recirculating aquaculture systems re-use nearly 100 percent of the water involved “and can be done in cities where demand is highest for local, fresh food,” he said.

Until now, though, such land-based systems have had limited success. Weeks says he’s seen between 80-90 percent of those efforts fail.

“How do we grow a product that’s high in omega 3 fatty acids, really healthy, and done so in a cost-effective manner? We struggled to find a way to do it,” Weeks said.

Hammond acknowledged that land-based aquaculture is a fledgling industry with high upfront costs. “But if you look at the technology and how far it has come recently, in the next few years we’re going to see it start to develop. There are ways to get this done.”

Hammond pointed to Growing Power in Milwaukee, a nonprofit community farming organization that uses aquaponics—the method of growing crops and fish together in a re-circulating system—to raise tilapia and yellow perch. “We think Michigan is positioned to lead [in land-based aquaculture] if we do things right here,” Hammond said.

But Weeks says producers are simply looking at existing production in Ontario and readily available sources in other Great Lakes and asking: “‘Why can’t we grow our own? I think that’s a fairly good argument.”