New Ray Hilborn study investigates environmental impact of aquaculture

A new study from fisheries expert Ray Hilborn compares the environmental impact of various forms of animal husbandry.

The study, which appeared in “Frontiers in Ecology and The Environment,” is an all-encompassing look on how animal protein production affects the environment.

“From the consumers' standpoint, choice matters. If you’re an environmentalist, what you eat makes a difference,” Hilborn said. “We found there are obvious good choices and really obvious bad choices.” 

Hilborn, a professor at the University of Washington’s School of Aquatic and Fishery Sciences, has been working on the study for almost a decade. The study investigates the impacts of animal-rearing including energy use, greenhouse gas emissions, fertilizer and other excess nutrient exposure to the environment, and emissions of substances that can cause acid rain. 

The study found industrial beef and catfish farming to be among the most environmentally costly meat and seafood production methods. On the other hand, farmed mollusks and small wild-caught fish pose the least amount of environmental impact. 

Because constant water circulation is needed to raise species like shrimp, tilapia, and catfish, livestock production generally uses less energy than aquaculture. But at the same time, beef production results in emissions of large amounts of methane. As a result, both catfish aquaculture and beef production contributes 20 times more greenhouse gases than farmed mollusks or farmed salmon and chicken. 

On the opposite end of the study, researchers found that farmed mollusks such as oyster and clams actually absorb some of the harmful fertilizers and excess nutrients that are emitted in other methods of animal protein production.

“I think this is one of the most important things I’ve ever done,” Hilborn says. “Policymakers need to be able to say, ‘There are certain food production types we need to encourage, and others we should discourage.’”

The study was partially funded by the Seafood Industry Research Fund (SIRF).