For decades, the hatchery programs on the Great Lakes have supported a $7 billion fishery industry, providing stock for recreational anglers and a handful of commercial operations.
In recent years, though, rising threats such as invasive aquatic species and algae blooms have prompted discussion about the sustainability of these fisheries, and whether aquaculture could bolster the lakes’ capacities for food production.
It’s no surprise that the state of Michigan, sharing coastline with four of the five Great Lakes, is thoroughly invested in the matter. Volunteer experts from three state departments are working together on a scientific panel to study the effects of commercial fish farming in the state’s waters.
The panel will examine the impact of net-pen aquaculture in particular, a fish farming method that uses floating offshore enclosures to house larger hatchery-raised fish.
The only commercial net pens in the Great Lakes are on the Canadian side of Lake Huron. Opponents of the practice say that’s where they should stay.
While a certain degree of contamination risk exists in closed, recirculating and flow-through hatchery facilities, that risk is heightened in net-pen aquaculture, where farmed fish share the water with everything beyond their enclosures.
Parasites and disease can exchange freely between fish inside and out, some detractors say. And without a flushing tide, waste may accumulate within the pen and contribute to excess nutrient loads, potentially leading to algae blooms.
Other opponents say that aquaculture would conflict with recreational angling, as both tend to target deeper waters just offshore.
According to proponents of net-pen aquaculture — including operators of Canada’s rainbow trout fish farms — excess nutrient loads are not a major issue, and may in fact benefit wild fish populations struggling to survive in the upper Great Lakes’ more sterile waters.
The Michigan Department of Natural Resources plans to “look at the issue of commercial net pens with a critical, deliberate eye, given the wide range of issues and interests affected,” DNR Director Keith Creagh said in a press release.
The public will have an opportunity to weigh-in on the subject before the panel in late June, and the state’s Environmental Quality, Natural Resources, and Agriculture and Rural Development departments will hold a workshop in the fall for its stakeholders.
“We want to have a firm understanding about the impact of aquaculture net pens on water quality, health of fish populations, and the Great Lakes ecosystem,” Creagh said in the press release. “Things that greatly influence quality of life for residents in the Great Lakes region.”
Top image: A commercial aquaculture pen off the coast of Maine. (Credit: NOAA National Ocean Service)