When you’re reeling in fish as part of a healthy diet, your decision often boils down to ocean vs. Old MacDonald. On their scaly surface, there’s really no difference between wild-caught and farm-raised fish. Beneath the surface, however, wild-caught and farm-raised fish swim in different directions.
According to Mary Ellen Camire, president of the Institute of Food Technologists, farm-raised means the fish were raised in tanks or enclosures, while wild-caught refers to fish caught using nets, hand lines, diver or traps. Beyond their sources, these two types of fish are different in terms of nutrition, although both do contain low levels of worrisome mercury.
Camire maintains that farm-raised and wild-caught are equally nutritious, as both types of fish get omega-3 fatty acids, a key nutrient, from algae, although in different ways. However, some experts draw a finer distinction between the two.
Tracie Hovey, director of “A Fishy Tale,” a documentary that’s critical of fish farming, says wild-caught fish are preferable to farm-raised. Wild-caught fish, she says, “are developing in ocean waters that are free of concentrated waste, free of growth hormones, and free of numerous other medicines and colorings that are used in farmed fisheries.”
Dr. Jack Wolfson, a cardiologist who wrote “The Paleo Cardiologist,” adds that levels of omega-6 fatty acids in farm-raised fish exceed those of wild-caught. These fats can lead to problems for people trying to strike a balance between bad omega-6 fatty acids and good omega-3 fatty acids, he says.
Furthermore, Wolfson says, farm-raised fish tend to contain less protein than their wild-caught counterparts. He attributes this to the fact that farm-raised fish are confined and, therefore, lack muscle development. By contrast, Wolfson says, wild-caught fish get more muscle-building “exercise” by swimming hundreds of miles during their lives.
On top of that, he says, vitamins and minerals in farm-raised fish are “synthetic and unnatural” because they come from farmer-supplied fishmeal, Meanwhile, Wolfson says, wild-caught fish contains “the nutrients as nature intended.”
Registered dietitian Joe Leech also raises concerns about farm-raised fish. He cites a scientific study released in 2004 that examined more than 700 salmon samples from around the world and found that average concentrations of PCBs (toxic chemicals linked to cancer) in the farm-raised variety were eight times higher than in the wild-caught version.
The Washington Post points out that the methodology behind the salmon study was called into question and that more recent research weighing the contaminant risks against the health benefits of omega-3s determined that every serving of salmon, wild-caught or farm-raised, “is a net positive.”
“If wild salmon is accessible to you and within your budget, then that’s a better option,” Leech says. “But farmed salmon is still very healthy, just slightly less healthy than wild salmon.”
In 2014, scientist Jim Fitzgerald, a sustainable seafood expert at the Environmental Defense Fund, told The New York Times that he recommends eating a mix of farm-raised and wild-caught seafood.
“You paint yourself into a corner if you say you don’t want to eat any farmed fish ever,” he told the Times. “It automatically removes 50 percent of the U.S. seafood supply from your choices.”
The Times mentions arctic char, rainbow trout and oysters as desirable options for farm-raised seafood, while praising Alaskan salmon, Atlantic mackerel and sardines in the wild-caught category.
The World Wildlife Fund says that at least in the salmon industry, fish farms are making significant strides. In 2013, the fund announced that companies representing more than two-thirds of global production of farm-raised salmon had agreed to meet certification standards of its Aquaculture Stewardship Council by 2020.
Philippe Toussaint, sustainable sourcing manager for European grocery chain Colruyt, says: “There is an increased demand for sustainable seafood, and it is important for retailers to provide consumers with choices. In parallel with wild fish products, we need aquaculture to meet the demand for seafood; however, it must be done responsibly.”