In the American Northwest, one of the main strategies to supposedly save endangered wild salmon has been the creation of hatcheries. While initially, this seemed to boost wild stocks and increase total biomass, the release of hatchery-reared salmon is now seen as more of a problem in itself than a ‘solution to’. While a landmark study found that the Pacific is reaching its salmon carrying capacity and “we’re seeing more total salmon now than we’ve ever seen before,” as commented on by lead author Randall Peterman, this does not mean that wild Pacific salmon stocks are faring better due to the hatchery industry.
Five species of Pacific salmon exist: Pink, chum, sockeye, coho and Chinook. Their population trends are complex, and recent resurgences in wild stocks have been explained by both favourable ocean conditions and constantly increasing hatchery fish production, yet these trends are not universal across the different species. Over the last 25 years, pink salmon populations have more than doubled, while other runs such as Upper Columbia River Chinook and Snake River sockeye are heading towards extinction.
Hatcheries, also known as artificial propagation, are a method of rearing fish to support wild populations and boost stocks for harvest. In the Pacific, hatchery-bred fish are reared in industrial facilities as eggs and then released as fry into rivers from where they travel into the sea. The Pacific Northwest now has over 150 industrial hatcheries, which constitute a multibillion-dollar industry. A staggering third of Alaska’s salmon harvest originates from five hatcheries located in the Prince William Sound. For years, hatcheries were promoted as the best solution for the augmentation of wild salmon stocks which are declining due to overexploitation and habitat loss. In 1970, hatcheries released 500 million young salmon. By 2008, that figure had jumped to 5 billion. These numbers mean that more than one-in-five salmon now originates from hatcheries. However, most scientists now believe that large-scale salmon hatchery programmes may pose the greatest single threat to wild fish welfare.
Hatchery programs are now viewed by many as highly dangerous and ill-advised practices. As one study points out, many hatchery managers still receive salary bonuses based on hatchery fish releases regardless of their survival and the implications for wild stocks. Four main issues exist; direct competition for resources between wild and hatchery fish, predation of hatchery fish on wild fish, the genetic dilution of wild fish stocks and increased fishing pressure on wild stocks.
Salmonids are known for competing for resources at every stage of their life. Millions of hatchery-bred fish are now adding to this pressure by reducing food resources for endangered wild runs. This competition is having negative effects on wild fish stocks of which a lower proportion is now surviving the ocean stage of their life cycle.
The illusion proponents of artificial propagation want to create is that hatchery fish boost wild stocks by spawning in the wild. These extra-spawners, rejected by the hatcheries, are released in the hope that they will add to naturally spawning populations. However, evidence suggests that these fish do not cope as well in the wild, and neither does the offspring of hybrid pairs. This comes down to the fact that hatchery managers select for fish that thrive in hatcheries; ones that can hatch in plastic trays and feed on an artificial diet. The reality of the wild is far different and wild fish must find mates, food, lay eggs in the gravel and avoid predation.
Moreover, hatchery salmonids possess far less diverse DNA due to limited broodstocks meaning they are not as genetically fit as wild salmon. This compromises their long-term survival. Further from this, they contaminate the genetic pools of wild runs when breeding between the two occurs. Until recently, little thought was given to matching hatchery runs with broodstock from their originating rivers. Wild salmonids owe their success to their diverse DNA which makes them so well- adapted to the conditions within their home river. For the most part, hatchery salmon possess much ‘dumber’ DNA.
When hatcheries are successful at adult fish production, the potential harvest rate becomes very high; often over 95% of the returning fish can be harvested. It is now a widespread concern in the Northwest that fisheries harvest rates have been allowed to match the potential productivity of hatchery stocks, causing wild stocks to be overfished. The net results of these high harvest rates are that as hatchery production has increased, wild stocks have declined and the Canadians have no more coho than they did 15 years ago-only now the coho they have comes from hatcheries rather than natural rivers.
Letting nature take its course
During my Sitka-Alaska field course, I was lucky enough to meet and listen to a representative of the Tlingit clan from the Eagle/Wolf (Ch’aak’/Gooch) moiety. The Tlingit people of Southeast Alaska have depended on wild salmon as their primary food source and their leader told us: “I don’t believe these hatcheries are doing any good. We have relied on wild stocks for centuries, and, left alone, they would bounce back just as they always have.” In support of his view, one controversial study suggested that hatcheries played little if no part in Alaska’s great pink salmon boom. The commercial pink salmon catch grew from 3 million in 1970 to over 20 million in the 1990s after the instalment of industrial hatcheries which are often credited for this increase. However, researchers Ray Hilborn and Doug Eggers argued that the same situation would have occurred without the hatcheries and that wild, not tank-raised populations would have increased due to naturally favourable ocean conditions.
Increased awareness of the ecological implications of hatcheries is slowly leading to policy changes. The past 10 years have seen a wave of hatchery reform aiming to help rather than hurt wild runs. In Alaska, one of the largest salmon hatchery operators: The Prince Willian Sound Aquaculture, asked to release an additional 95 million pink salmon fry and were met with a refusal from The Alaska Department of Fish and Game who wanted to safeguard wild salmon runs against genetic mixing with hatchery stocks and who are concerned with pushing the North Pacific towards a tipping point. They did however approve the company’s release of chum and sockeye fry.
While slowing down hatchery production and releases is possible and happening in the US, it’s much more tricky to implement these changes elsewhere. In Russia, pink salmon hatchery production has aggressively been increased and more hatcheries are being built. This will only add more pressure on the wild North Pacific common pool, but no nation has the political power to stop them. Peterman tells a journalist: “Quite frankly, there’s no regulatory authority right now.”
It may really be time to consider redirecting resources to manage hatcheries in a more informed and sustainable manner, and to protect and better mange wild salmon habitats and populations.
As one clever headline put it, perhaps salmon hatcheries are nothing more than a ‘Hatch-22’…