Bad salmon

atlantic salmon

Atlantic salmon/Hans-Petter Fjeld (CC-BY-SA) photo

SEATTLE – Near panic has set in here over the spill of anywhere from several thousand to as many as 300,000 Atlantic salmon in the waters of nearby Puget Sound.

“Farmed salmon ‘heading to every river in Puget Sound’,” headlined the Seattle Times above a story warning that “the Lummi Nation has declared a state of emergency and is paying fish buyers to take the Atlantic salmon brought in by their fishermen, said Merle Jefferson, director of natural resources for the tribe.

“Jefferson declined to say how much the tribe is paying. ‘It is not going to be cheap, that is all I can say,” he said. ‘It’s just like an oil spill, we are trying to contain it as best we can.'”

Suffice to say, this relatively small, accidental spill is being viewed differently than the huge and intentional, annual spill of nearly 2 billion Pacific salmon into the waters off Alaska.

“‘Environmental Nightmare’ After Thousands Of Atlantic Salmon Escape Fish Farm” is how NPR pitched the story.

The bad salmon

Atlantic salmon are a fish humans have tried unsuccessfully to stock in the Pacific Ocean more than 100 years. None of the intentional efforts to colonize the Pacific with these fish have worked.

“The most recent attempt by Washington Department of Fish & Wildlife Conservation was in 1981 when attempted introductions were made via the release of cultured Atlantic salmon smolts,” that agency admits on its website. “No adult Atlantic salmon adults returned as a result of the releases.

“In 1996, 1997, and 1999 there were large escapes of approximately 107,000, 369,000, and 115,000 fish, respectively.”

The 1997 spill of Atlantics is larger than upper limit of the current spill. None of those fish colonized any Washington state waters.

Canadian biologists in the late 1990s did discover Atlantic salmon successfully spawning in rivers in British Columbia and concluded in a study released in 2001 that “successful
colonization is possible. How the presence of competitor or predator species in a natural, more heterogeneous environment may alter our findings also remains to be investigated. Numbers of Atlantic salmon adults in many Vancouver Island rivers are now adequate to undertake such natural experiments.

“Our results suggest that although per capita success is low, escaped Atlantic salmon that
survive to ascend coastal B.C. rivers are capable of successfully excavating redds and spawning viable eggs.”

As of yet, more than a decade later, none of these fish are known to have established viable, reproducing populations. As an invasive species, Atlantic salmon are not dandelions.

A 2008 report commissioned for the Food and Agriculture Organization (FAO) of the United Nations concluded it is possible that Atlantics could colonize a stream or streams along the Pacific Coast, but noted “spawning of escaped farmed Atlantic salmon has not been documented in Chile or Tasmania. The Atlantic salmon is a poor colonizer outside its native range. The probability that escaped Atlantic salmon will establish populations where the species is exotic seems low, but the possibility cannot be ruled out.”

There is, however, one thing that can be ruled out: A spill of Atlantic salmon is nothing “like an oil spill.” An oil spill, as Alaskans discovered when the Exxon Valdez oil tanker hit the rocks, has immediateand massive impacts on birds, marine mammals and the intertidal areas of beaches on which oil washes ashore.

Bad spill/good spill

Still, a spill of thousands or hundreds of thousands of Atlantic salmon is a bad thing. The fish could get into Washington streams and rivers, maybe even some waters in British Columbia and Oregon, and compete with wild fish on the spawning grounds.


But at a population level, the Puget Sound fish spill – while large – appears to pose only a small environmental risk based on the outcome of similar spills in the past. The same cannot be said about the deliberate spills of billions of hatchery-spawned fish into the ocean every year.

“…It appears that the issues of disease transfer between wild and farmed fish and of escapes are minor. Instead, declines in wild stocks are attributed to habitat degradation, changing oceanic conditions, and effects from breeding with public hatchery fish, together with high harvest rates and a decrease in adult size,” The Fraser Institute, a Canadian think tank reported in 2005. “Any environmental impacts from escaped farmed Pacific salmonid are likely to be dwarfed by the number of releases by public hatcheries, which are breeding native, wild species.

“Public hatcheries are part of the (Canadian) Department of Fisheries and Oceans’ strategy to enhance salmon stocks. These facilities fertilize and then incubate eggs from local fish, rearing them until the fish can be released into the wild.

“In 2003, for each Chinook that escaped from a (British Columbia) fish farm, the public hatcheries released 25 million such fish, and for each coho that escaped, the hatcheries released 20 million coho.”

The Fraser Institute, according to its website, is “an independent research and educational organization with offices in Vancouver, Calgary, and Toronto, and international partners in over 70 countries. Our work is financed by tax-deductible contributions from thousands of individuals, organizations, and foundations. In order to protect its independence, the Institute does not accept grants from government or
contracts for research.”

Finding the money to conduct population-level studies of the ecological consequences of adding hundreds of millions of new hatchery fish to the seas is not easy because politically powerful and well-organized commercial fishing organizations, fishermen and processors consider the hatcheries a good thing – a very good thing.

About 93 million hatchery fish worth $125 million to commercial fishermen were harvested in Alaska in 2015, according to the Alaska Department of Fish and Game. Those fish accounted for more than a third of the statewide harvest of 263.5 million salmon that year.

Hatcheries have become big business in the 49th state, but the Fraser Institute has not been the only entity to raise questions about possible negative environmental impacts.

“The abundance of (hatchery) pink salmon, owing to their life history strategy, is an uncommon case of too many fish in the sea, and the ecosystem-scale effect they have needs to become part of international resource common-pool policy discussions that include seabirds, and by extension additional competing species,” Alan Springer from the University of Alaska Fairbanks and Gus Van Vliet, a retired scientist from the Alaska Department of Environmental Conservation, concluded in a 2014 study published in the proceedings of the National Academy of Sciences.  

The two scientists found that pink salmon were so heavily grazing the North Pacific Ocean and the Bering Sea that short-tailed shearwaters, which eat similar foods, were going hungry. Captured skinny shearwaters, a Southern Hemisphere seabird that seasonally migrates north, coupled with ” five times higher strandings of shearwaters on the coast of eastern Kamchatka, provided the first evidence (to the authors’ knowledge) of the influence of pink salmon over a competing species besides other salmon,” they wrote.

And the influence was not good.

Big Alaska impact

Alaska is a big player in North Pacific fish spills.  Alaska hatcheries intentionally dump salmon in the ocean not by the hundreds of thousand or even the hundreds of millions, but by the billions.

“Since 1995, annual releases have ranged from about 1.4 to 1.7 billion juveniles,” according the annual Alaska Fisheries Enhancement Annual Report 2016 from the Alaska Department of Fish and Game. “Most of the 2016 releases were from pink and chum salmon eggs collected in 2015, and the remainder from Chinook, sockeye, and coho salmon eggs collected in 2014. About 1.7 billion juvenile salmon were released in 2016, which was near the historic high.”

These hatchery fish have since dispersed widely in Alaska. There are no indications hatchery fish have ever spread disease to wild fish in the 49th state, but they have influenced the gene pool – especially in Prince William Sound – and in a study published in Ecosphere this June, researchers reported that “straying” hatchery fish have flooded some Alaska rivers in such numbers that they helped cause “salmon-induced oxygen depletion” that choked and killed wild fish.

“…Human impacts such as hatchery straying and water diversion,” that study said, “may increase the probability of hypoxia. Comprehensive data on salmon straying rates and mechanisms for straying behavior are sparse, but pink and chum salmon appear to have the highest propensity for straying among all Pacific salmon species.

“In Prince William Sound, Alaska, 77 percent of surveyed streams contained hatchery pink salmon from three or more hatcheries, and hatchery strays comprised zero to 98 percent of pink salmon escapement within individual streams.

“In Sawmill Creek (in the Alaska Panhandle) during 2015, hatchery chum salmon strays comprised 51 percent of (the) total number of spawning chum….An earlier Sawmill Creek study conducted in 2009 and 2010 found that 78 percent and 44 percent of sampled chum salmon carcasses, respectively, were hatchery strays.

“Even though stray rates tend to decrease as the distance from hatchery release sites increases, continuing hatchery production levels and widely distributed juvenile salmon release sites in southern Alaska will likely keep the potential for continued
straying to many coastal river systems high.”

The study warns that over time this could seriously deplete wild stocks or maybe even replace them with hatchery fish. Deaths of wild fish from lack of oxygen could lead to a continued decline in the number of those returning to a stream, while “hatchery
populations, which only require small numbers of spawners to maintain production goals, do not receive this population feedback and have the potential to continue supplying large numbers of strays to streams in years immediately following
die-off events.

“Thus, resident fishes in streams that are repeatedly populated with high densities
of straying salmon may experience long-term declines in productivity.”

In Washington, at least, the potential salmon invaders from the Atlantic are identifiable. In Alaska, where ever-increasing numbers of Pacific salmon spawned in hatcheries keep appearing in wilderness streams, the wild fish could be replaced with salmon that look exactly the same on the outside but are genetically hatchery salmon on the inside.

The long-term consequences of all this? Nobody really knows, although the data gathered to date in Alaska makes the problem look no worse, albeit no better, than the problem caused to date by escaped farmed fish in Washington state and British Columbia.

More should eventually be known. The Alaska Department of  Fish and Game is now early into a study slated to run through 2023. 

For now, though, the only bad salmon are the tens or hundreds of thousands of farmed fish spilled accidentally in Washington state. The nearly 2 billion hatchery fish spilled intentionally in Alaska remain the good salmon.










6 replies »

  1. In the Columbia Rv system with a long history of hatchery releases to ‘replace’ wild stocks, there is evidence that high densities of hatchery fish in streams negatively impact the remaining wild fish. Fascinating example of unintended consequences.
    See for more information

Leave a Reply