Aquaculture in the Great Lakes

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Challenging Harmful “Net-pen” and Antiquated “Flow-through” Aquaculture Operations in the Great Lakes

Commercial aquaculture or fish farming takes various forms in tanks, ponds, rivers, lakes, and the ocean. Current legislative proposals are now on the table to use the open waters of the Great Lakes on the U.S. side for commercial net-pen aquaculture and to expand antiquated “flow-through” operations on some tributaries such as the Au Sable River, one of the most prized blue-ribbon trout streams east of the Rockies.  

The industry promises a local, sustainable source of protein, but commercial aquaculture operations typically deposit high concentrations of fish waste, feed, and antibiotics directly into public waters. In addition, diseases and escaped fish threaten wild fish populations.

Environmental Risks of Aquaculture

Environmental Risks of Aquaculture


With clear warnings from the scientific community that current commercial aquaculture practices can cause substantial harm to wild fish stocks, FLOW is working with a coalition of public interest, angler, and conversation groups to ban commercial cage aquaculture in the Great Lakes. Such a private use would expressly violate public trust law, which requires the Great Lakes to be managed for the long-term use and enjoyment of
all people. Privatizing the bottomlands for the benefit of a few puts the entire system at risk -- a system that current supports an annual $7 billion sports and commercial fishery according to the Great Lakes Fishery Commission.

In summary, proposed net-pen aquaculture in the Great Lakes and existing antiquated flow-through aquaculture operations on our rivers violate our public trust and environmental laws and threaten the health and vitality of the Great Lakes by:

  1. Releasing waste laden with nitrogen and phosphorous from both of these types of operations directly into our waters. This creates another substantial input for the harmful algal blooms and hypoxic conditions that have been devastating the Great Lakes for decades. A typical 200,000-fish salmon farm releases as much fecal matter as a city of 65,000 people does.

  2. Leading to the inevitable escape of fish, which threatens the genetic diversity and health of wild fish populations. Farmed fish are domesticated livestock that have been bred for certain traits that are different from the wild fish prized by the state’s sport fishery and essential to our ecosystem.

  3. Increasing the risk of disease. Diseases started in net-pen and flow-through aquaculture operations can quickly spread to wild populations, threatening our ecosystem and our sport and commercial fishing industry.

  4. Undermining more environmentally friendly aquaculture systems. Self-contained operations capture and treat their waste, instead of dumping it into our common waters and shifting the cost to the public.

  5. When combined with climate change, water levels, invasive species, nutrient levels and algal blooms, the cumulative threat to the Great Lakes is unknown and unacceptable.
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