Populations of wild salmon in fish farms, which are meant to boost the wild salmonid numbers across the globe, are facing negative impacts, according to an analysis.
Fish farms or hatcheries are where fish are raised in enclosures to be sold as food. It is the fastest-growing area of animal food production. According to the United Nations Food and Agriculture Organization, roughly 32 percent of world fish stocks are overexploited, depleted or recovering and fish farming is seen by some as a solution to the overfishing problem. However, the damage caused by fish farms varies, depending on the type of fish, how it is raised and fed, the size of the production, and where the farm is located.
Farmed salmon are known to reach maturity faster than wild ones, a trait they can pass on to their offspring, making it more difficult for subsequent generations to breed. This accelerated maturation also has the effect of increasing their “boldness and aggression,” a report from The Cooldown explained, which increases the chance that the fish will be killed while still in their juvenile stage. Farmed fish can also carry diseases that pose a danger to wild populations.
According to the Alaska Beacon, an analysis of more than 200 studies shows the negative impact wild salmon populations are facing in the fish farms such as poor health and reproductive outcomes.
“An analysis of more than 200 studies on hatcheries programs meant to boost salmonid numbers across the globe—including salmon, trout and whitefish—shows that nearly all have had negative impacts on the wild populations of those fish. Most commonly, hatchery fish reduced the genetic diversity of wild fish, leading to poor health and reproductive outcomes,” the Alaska Beacon wrote on Tuesday.
The global studies, which took place between 1971 and 2021, were analyzed by scientists at the nonprofits Trout Unlimited based in Virginia, and The Conservation Angler out of Washington, along with the University of Washington, the University of Montana and the Université Laval, in Quebec, Canada.
The analysis was published in July in the journal Fisheries Management and Ecology.
Newsweek has reached out to Trout Unlimited and Conservation Angler via email for comment.
According to the analysis, of the 206 studies more than 80 percent revealed hatcheries programs had adverse effects on wild salmonids. Of the 3 percent of hatcheries globally that were found to benefit wild populations, the majority were stocked with wild fish that were bred and released in small numbers to boost severely depleted wild populations.
John McMillan, science director at The Conservation Angler who worked on the analysis, told the Alaska Beacon that despite research showing fish farm programs can hurt wild fish populations, it is important to know what it “means to us.”
“It’s frustrating from a scientific point of view, because you can see what the science suggests, but it’s understandable why we’ve been reluctant to move our position on hatcheries, because of the social implications,” McMillan told the Alaska Beacon.
“This is one of those things, like climate change, where we have to sit back and think about our relationship with the animal, what it means to us and how much we want to give up so these animals can truly, potentially rebuild themselves,” McMillan added.
Earlier this month concerns surrounding wild salmon in fish farms were raised when the International Union for Conservation of Nature (IUCN) released its first red-list assessment for the freshwater fish category, finding that roughly 20 percent, or one-fifth, of all such species now face the threat of extinction.
According to the IUCN’s report, the Atlantic salmon, a species known to live in freshwater and saltwater habitats, once classified as “least concern,” has now been moved to “threatened.”
As noted in a report from The Guardian, these wild salmon populations in the Atlantic are facing a unique concern due to the trend of farmed salmon escaping captivity and intermingling with them, as the outlet noted that breeding between wild and farmed salmon produces offspring that are less able to adapt to the effects of climate change.