If you live in Michigan or enjoy recreating on the Great Lakes, you’ve likely heard about the controversy on net-pen aquaculture. But if you haven’t, we worked with Jennifer McKay, the policy specialist at Tip of the Mitt Watershed Council in Petoskey on an FAQ about environmentalists’ concerns with Great Lakes net-pen aquaculture.

What is net-pen aquaculture?

It’s a process of growing fish. Young fish start in a land-based facility and are then transferred to a mesh net pen or hard cage structure in a lake or ocean to finish growing.

What’s the debate about?

Net-pen operations are not forbidden under Michigan law, but currently, there are no commercial net-pen aquaculture operations in Michigan’s open waters of the Great Lakes. There are several opposing bills that if passed would either ban net-pen aquaculture or allow it. Groups hoping to ban net-pen aquaculture believe it could pose serious risks to the Great Lakes while supporters say it will help meet Michigan’s seafood demand and create jobs and revenue.

Has net-pen aquaculture been done in the Great Lakes before?

“While there are some aquaculture operations in Ontario’s Great Lakes waters, the province hasn’t issued a new permit in two decades,” McKay says. “In addition, an operation in Lake Huron’s North Channel was shut down because the huge amount of fish waste it generated triggered algae blooms and created an oxygen-starved ‘dead zone.’ Surveys nearly a decade later found the local environment still hadn’t fully recovered. The Ontario Ministry of Natural Resources also conducted research on two other sites in the early 2000s and found that effluent limits were exceeded outside of the boundaries identified in the permits.”

What are some of the possible risks to the Great Lakes?

According to McKay, proposed net-pen farms would:

Dump untreated waste directly into the lakes, adding tons of phosphorus and nitrogen each year and potentially triggering toxic algae outbreaks like the one that shut down Toledo’s drinking water source in 2014.
Provide a breeding ground for diseases that could spread from caged fish to wild populations, putting the Great Lakes fishery and ecosystem at risk.
Inevitably lead to escapes that can have wide-ranging negative genetic effects on native populations and erode the wild fish population’s ability to adapt and survive.
Lead to introductions of invasive species if non-native species are raised in the net pens.

Who are the main supporters and opponents of Great Lakes net-pen aquaculture?

Supporters of net-pen aquaculture:

Michigan Aquaculture Association
Michigan Farm Bureau
Michigan Sea Grant
Owners and operators of aquaculture facilities or entities involved with the aquaculture industry

Opponents of net-pen aquaculture:

Tip of the Mitt Watershed Council
Michigan Environmental Council
Michigan United Conservation Clubs
National Wildlife Federation
Michigan Trout Unlimited

An EPIC-MRA poll conducted in January showed that 68 percent of Michigan voters oppose allowing commercial net-pen aquaculture in Michigan waters of the Great Lakes, including 77 percent opposition in Northern Michigan. Many of Michigan’s Tribes also expressed serious concern regarding aquaculture in the Great Lakes.

Are there other options?

Aquaculture occurs in three basic forms: closed systems, stream flow through systems, and open water net pen systems. While each has its own pros and cons, McKay believes closed systems offer the most viable and responsible means to aquaculture development in Michigan. “Ideally suited to the vacant warehouses plentiful in rebounding cities, these promising ventures recirculate water and capture the waste,” McKay says. “Completely separated from rivers and lakes, these operations can be a sustainable source of nutritious local food and economic development while keeping the Great Lakes and inland waterways protected.”

Has scientific research been conducted on the issue?

Michigan’s departments of Natural Resources, Environmental Quality, and Agriculture and Rural Development co-authored a report released on March 9 recommending that Michigan should ban net-pen aquaculture in areas of the Great Lakes under the state’s jurisdiction. The agencies’ full evaluation can be read here.

The synthesis report gave the following three conclusions:

Given the ecological and environmental risks and uncertainties, commercial net-pen aquaculture would pose significant risks to fishery management and other types of recreation and tourism.
The $3.3 million in startup costs to implement a commercial net-pen aquaculture program by the state to protect the public’s interest in the Great Lakes and provide the stated expected service to the industry are not provided through any conventional funding models available to the state departments. There would need to be a new funding stream identified for this industry effort to support initial costs as well as the $2.33 million needed annually to monitor and maintain the program and protection of the state’s resources. This level of public investment for an estimated return of $10 million (under the modeled scenarios for two facilities) does not appear to be a prudent use of the state’s resources at this time.
Regulatory authority does not currently exist to issue registrations for commercial aquaculture in the Great Lakes.