Abundant Salmon, Troubled Waters

The industrial-scale production of food animals isn’t something that only happens on land. Consider the salmon, the fish that commands the spotlight in our supermarket seafood cases, restaurant menus, and cooking shows.  

Left to their own devices, these majestic creatures aren’t a likely candidate for the regimentation of the factory farm. They hatch in inland freshwater streams, often hundreds of miles from the shore. They migrate to the ocean, where they range over additional hundreds of miles, developing fatty, pink-hued flesh from gobbling up krill, shrimp, and algae. Then, displaying a geospatial dexterity that science has not fully figured out, they swim upstream against fierce currents to their original birthplace, to spawn the next generation. On the northern reaches of both coasts of the present-day North America, these cold-water fish thrived for millennia alongside indigenous peoples, for whom they formed a dietary staple.  

These days, U.S. and Canadian wild salmon  runs are under extreme pressure. On the west coast, you have to go all the way up to Alaska to find robust commercial salmon fisheries. On the U.S. east coast, Atlantic salmon have been on the endangered species list for nearly a quarter of a century. “Wild Atlantic salmon are only found in a few rivers in Maine,” the National Oceanic and Atmospheric Administration reports. Fishing them is banned.  

And yet, salmon is by far our favorite finfish to eat. Each year, we consume more salmon than our second and third most popular species (canned tuna and tilapia) combined. What happened? How did our access to salmon boom, even as our wild salmon fisheries (save for that of Alaska) essentially collapsed? How did its place in supermarket seafood cases, restaurant menus, and cooking shows soar, even as its ecological niche dwindled?  

In their deeply researched, crisply written 2023 book Salmon Wars: The Dark Underbelly of Our Favorite Fish, the husband-and-wife team of Douglas Frantz and Catherine Collins have answers—and that’s why we invited them to appear on the newest episode of Unconfined Podcast.  

Essentially, they show, overfishing coupled with environmental factors like warming ocean waters, pollution, destruction of inland habitat, and—most crucially—dams placed wild salmon on a downward descent, not just in North America but also in their other main stomping ground, northern Europe. Then, in Norway in the 1970s, an industry arose devoted to confining salmon and raising them by the thousands in open ocean pens—in the very waters frequented by Norway’s own dwindling wild salmon run. The hope, Frantz and Collins make clear, was that the emergence of farmed salmon would ease pressure on wild stocks, helping them to bounce back. What happened instead was that a multi-billion-dollar farmed salmon industry emerged—and siting them on the same shores utilized by wild salmon proved cataclysmic.  

What the industry had created was factory-scale livestock farms on the water. And as Unconfined listeners will know, concentrating thousands of units of the same species in a finite space concentrates their waste and makes them vulnerable to all manner of pathogens—which in turn call forth a cascade of toxic chemicals. An excellent example is the once-humble, now mighty salmon louse. These aquatic creatures operate by attaching themselves to the skin of salmon and then chomping down on their skin and sipping their blood. Happily, wild salmon and lice populations achieved a rough balance over their time on the planet—wild salmon developed resistance to the point that sea lice can do their thing without causing significant harm. (If they hadn't evolved to thrive despite the nibbling of their parasites, of course, wild salmon would have gone extinct long ago. ) 

But when the fish are stuffed together by the hundreds of thousands in pens open to the coastal sea, salmon lice encounter a veritable banquet. Left uninhibited, it turned out, sea lice populations will overwhelm cooped-up salmon. Undaunted, the salmon industry resorted to a prized tool of land-based industrial agriculture: chemicals designed to kill pests. The idea is simple: if farmed salmon can't fight back sea lice with their own defenses, dump something into the water to do the job for them. Of course, residues of these compounds end up in the water, along with uneaten fish feed and manure, fouling coastal waters. .  

Worse —surprise!—sea lice are constantly adapting to the chemicals used to control them, meaning that sea lice remain a problem. Pressure from this pest is just one of the reasons why keeping salmon alive under confinement remains a huge challenge. As Frantz notes in our conversation, the mortality rate on salmon farms runs as high as 25 percent—meaning that as many as one in four fish die before harvest.  

And for the wild salmon that traverse the same waters, the sudden preponderance of sea lice proved overwhelming. In 2020, nearly half a century after the industry’s beginnings, “wild salmon still struggle, despite many mitigation efforts,” the Norwegian Scientific Advisory Committee for Atlantic Salmon reported. “Increased mortality due to salmon lice is an important reason.”  

As you’ll hear from Frantz and Collins, the menace of salmon lice is but one of the negative externalities generated by the salmon industry. Another huge one is the feed problem. Mass-producing carnivorous fish requires titanic amounts of wild fish.  

Veteran journalists and researchers with a knack for the telling anecdote, Frantz and Collins lay all of this out in our interview with concision and wit. They also explain an emerging alternative to the open-pen system—land-locked salmon farms that don’t pollute coastal waters or infest them with lice, although they do present the same feed challenges as their seaborne peers. Their product is more expensive than bog-standard open-pen salmon, Collins explained, and won’t likely be competitive until those politically potent operations are forced to include the messes they create as costs on their balance sheets.  

That would require a sea change (pun intended) in governments’ willingness to regulate a powerful industry in all the major regions that supply our salmon habit.  There are sign signs of such a shift afoot. In June, the Canadian government announced a ban on open-net salmon farming in British Columbia, a major industry production site, by 2029.  

In the meantime, Collins’ advice to consumers echoes that of everyone else I’ve ever talked to: diversify your diet away from farmed salmon and look for aquaculture products that actually benefit coastal waters. Examples include oysters (pricy) and mussels (economical), both of which are packed with omega-3 fatty acids, like salmon. For wild fish, try species caught near where you live, that aren’t overfished. Here in Baltimore, I plan to seek out the local delicacy known as “lake trout,” which is actually silver hake, an abundant fish in Mid-Atlantic sea (not lake, despite the local name) waters. The Monterey Bay Aquarium’s Seafood Watch program—the best available consumer guide to choosing sustainable fish—rates it a “good alternative.” Liz Nussbaumer, project director of Aquatic Food Systems and Public Health at the Center, recommends people in the Mid-Atlantic region give blue catfish a try. “It’s invasive to the Chesapeake, harms crab fisheries, and is a wild-caught, abundant, affordable fish sold widely,” she says. 

For recent CLF work on salmon and aquaculture generally, go here.