In addition to healthful and satisfying lean protein, some types of fish also provide ample amounts of the omega-3 fatty acids that are essential to heart, skin, brain, mood, eye, and immune system health. And yet 40 percent of Americans eat seafood only once a month, or less. The rest of us, on average, don’t do much better. The fish and shellfish we do choose to eat is often fried and battered or breaded—preparations that tend to cancel the health benefits inherent in the seafood itself. We eat shrimp most frequently—almost always imported— followed by canned tuna and salmon. Many of us believe, with good reason, that tuna and salmon are the best choices for healthy eating. Farmed tuna isn’t an option, because it doesn’t exist. All tuna is wild caught. On the other hand, farmed salmon is readily available across the U.S. and is frequently touted as a good dietary choice.
Wild Salmon, or Farmed—Is There Really a Difference?
Many of us don’t see a difference between farmed salmon— often sold as “Atlantic salmon”—and wild salmon. After all, it’s the same fish, right? Surely it has healthy amounts of those revered omega-3s. It certainly looks the same on display in the fish market, and at the grocery or warehouse store. Since farmed salmon is available everywhere, and it’s so much cheaper than wild salmon, isn’t it the best choice if we want to add more fish to our diet?
No. Not even close!
Not all fish offer the same benefits, and that’s particularly true where wild and farmed salmon are concerned. They are genetically different fish, and their nutritional profiles differ—as do the effects of their life cycles and harvest on the environment. Salmon, perhaps the most popular type of fish raised in farms at sea, poses a particular set of problems for the environment and for public health. Let’s look at the impact of salmon farming on the environment, first.
The Environmental Impact of Industrial Salmon Farms
It’s no longer news that our oceans are in trouble from pollution and uncontrolled fishing. Industrial-scale fish farming— one part of what’s generally referred to as “aquaculture”—seemed to represent a reasonable solution to the problem of declining numbers of wild fish and the increasing worldwide demand for food. But aquaculture practices vary from country to country, making many types of farmed seafood unsustainable or unhealthy— or both.
- The waste from millions of captive fish empties directly into the ocean, polluting the water with untreated sewage, toxic chemicals, and other wastes.
- Approximately three million genetically identical salmon escape from their pens each year, interbreeding and often out-competing with populations of genetically superior wild salmon.
- Captive farmed salmon make ideal hosts for highly contagious diseases and parasites; escapees spread them to wild fish.
- As they grow, carnivorous and voracious farmed salmon need increasing amounts of wild-caught fish for food, thus competing directly with humans and other fish species for this valuable yet diminishing resource.
Currently, it takes the equivalent of three pounds of wild fish from the world’s oceans to produce one pound of farmed salmon. Entire species are significantly threatened because they’re taken in such large numbers to feed salmon raised in pens. Hundreds of thousands of farmed salmon, packed together in cages in the open sea, inevitably attract natural predators. To deter them, salmon farmers place steel nets around and above cages that also entangle dolphins, seals, and even birds, including endangered eider ducks. Some of the most sensitive breeding areas and migratory paths for dolphins, whales, and sharks are adversely affected.
Salmon farmers also employ acoustic devices that emit a noise comparable to the sound of a jet engine at takeoff, causing physical pain in the ears of seals, the targeted predators. But the devices also harm dolphins, porpoises, and whales— collateral damage, if you will—and force them out of their native habitat.
Farmers also shoot seals and sea lions, who feed on salmon in the wild and are attracted to the captive fish. It’s estimated that more than 5,000 sea lions and seals have been killed since 1990 by fish farmers in British Columbia.
Shooting, acoustic harassment, and entanglement all inflict inhumane deaths on birds, seals, porpoises, and other marine animals. A study of a single salmon farm in British Columbia found that in one four-year period, more than 400 harbor seals, 38 sea otters, 29 sea lions, one harbor porpoise, 16 herons, and one osprey were killed by anti-predator devices.
Salmon farms also pose another great threat to species that depend on wild salmon. Wild Atlantic salmon are all but extinct, and the process has begun in the Pacific as salmon farms spread and increasing numbers of genetically uniform fish escape into the ocean. No one knows if all the species that rely on wild salmon as their food source will adapt to the intruder species. If not, they may lose a critical food source. Native marine animals, including whales, are being forced out of their historic habitat by salmon farms. They lose access to migration routes, essential spawning grounds, and foraging areas. The long-term prognosis for this loss of habitat is likely to be disastrous for many threatened and endangered marine animals, birds, and whales.
The Impact of Farmed Salmon on Personal Health
Beyond the damage inflicted by industrial salmon farms on the environment, farmed salmon poses a significant threat to human health. What’s bad for the greater environment is likely to be bad for your body.
More than ten years ago, the World Health Organization warned of the potential risks to human health from the growing popularity of farmed salmon. Today, most of the salmon consumed in the U.S. is still farm-raised and imported, with little oversight regarding use of antibiotic drugs or additives.
A diet that includes regular portions of wild-caught salmon can promote good health. Farmed salmon, by contrast, has fewer dietary advantages and several significant disadvantages.
- Farmed salmon can contain high concentrations of polychlorinated biphenyls (PCBs) and other dangerous contaminants not found in wild salmon.
- Artificial coloring, toxic byproducts, antibiotics and other drugs, and cancer-causing contaminants are present to various degrees in farmed salmon tissue, often at levels that can adversely affect human health.
- Farmed salmon tends to have many more pro-inflammatory omega-6 fatty acids than the anti-inflammatory—and thus, much more desirable—omega-3s.
Superior Salmon, Naturally
Unlike penned, grain-fed, flaccid, white-fleshed farmed salmon, wild salmon spend several years feeding on the sea’s natural foods and straining against the strong, cold currents of the North Pacific before migrating thousands of miles to the headwaters of their birth rivers. They derive ample omega-3s and vitamin D from their food supply and life cycle, and they come by their red color naturally. It’s not added to their food as a supplement.
Wild salmon offer better flavor, better texture, and a nutritional profile that’s far superior to any farm-raised fish, which are confined in a tight space throughout their lives and fed a grain- and fish-based diet laced with antibiotics to fend off diseases and compounds to turn their white flesh, red.
Wild Salmon Versus Farmed: Nutritional Distinctions
Wild salmon and farmed salmon contain comparable amounts of the omega-3 fatty acids that make fish such healthful food. In fact, farmed salmon may contain somewhat higher levels of omega-3s.
Unfortunately, the omega-3s in farmed salmon come from feeding them “chow” made of fish meal or fish oil derived from mass harvesting of small fish nearer the bottom of the marine food chain: a practice with alarming implications for the future of the marine ecosystem.
And, compared with wild salmon, typical farmed salmon contain much higher levels of omega-6 fatty acids, which already occur in extreme excess in typical Western diets: most Americans consume 20 to 30 times more omega-6 fatty acids than omega-3s. Experts recommend consuming no more than five times as many omega-6s than omega-3s.
When consumed in such excessive amounts, omega-6 fatty acids blunt the benefits of omega-3s to a very substantial extent and can promote chronic, “silent” inflammation and the diseases associated with it, including heart disease, diabetes, senility, and cancer.
In fact, the intriguing results of a recent study suggest that consuming standard farmed salmon, raised on diets high in omega-6 fatty acids, raises people’s blood levels of the inflammatory chemicals linked to increased risk of cardiovascular disease, diabetes, Alzheimer’s and cancer.
Salmon farmers claim they’re striving to reduce the omega-6 content of farmed salmon feed, but to the extent that they replace omega-6-rich vegetable oils and grains with costlier fish meal or fish oil, this will contribute to further over-fishing of species closer to the bottom of the marine food chain, with negative impacts throughout the oceanic ecosystem.
Research published in recent years makes it clear that vitamin D is a much bigger factor in human health than previously thought, reducing the risks of osteoporosis, fractures, and major cancers. New findings show that wild salmon are the best food sources of vitamin D. For example, while a cup of milk contains only 100 IU of vitamin D, there are up to 700 IU in a 3.5 ounce serving of sockeye salmon.
Farmed salmon contain only one-quarter as much vitamin D as wild salmon, according to independent tests by researchers at Boston University.
Selecting Wild Salmon Helps to Save Wild Salmon
As paradoxical as it may seem, to save wild salmon it helps to choose it over farmed salmon products. Wild salmon are sustainably harvested—the economic well-being of fishing communities depends on it and choosing it over farmed salmon secures a place for wild salmon in the marketplace. Aquaculture is an increasingly important source of seafood, and shows great promise to help feed a hungry world— when it is practiced sustainably. But the environmental sustainability of current salmon farming operations is doubtful, and the nutritional profiles of their products remain inferior. So, at least for the foreseeable future, until and unless advances in aquaculture make salmon farming safe for the environment and for public health, it’s best to choose wild salmon over farmed. Consider the slightly higher price an investment in your own well-being—and the health of the world.