Areas identified as ripe for colonization by salmon as glaciers retreat/Nature Communications

As the global climate warms, salmon in Canada and the Pacific Northwest might be facing new barriers in the never-ending struggle to survive, but a peer-reviewed paper published in Nature Communication earlier this month says the fish could find large new homelands to explore in Alaska as glaciers retreat and expose new stream habitat.

“Gains in salmon habitat are substantial enough that they could lead to new sizable increases in salmon production in some locations,” according to a global team of authors led by Kara Pittman from Simon Fraser University in British Columbia, Canada. “For example, one kilometer of suitable stream habitat can produce approximately 500 to 1500 juvenile coho salmon. Thus, with hundreds to thousands of kilometers of new habitat being created from glacier retreat, there is a potential to produce hundreds of thousands to millions of additional juvenile salmon, depending on species.”

As with any change in the environment, there are inevitably winners and losers as humans should recognize. Were it not for the planet’s chance encounter with an asteroid, dinosaurs would likely still rule the earth, and we wouldn’t be here.

But amid today’s global concern about future climate change, the places and the species likely to benefit from a warming planet are regularly overlooked, which is a perfectly natural reaction given a naturally homocentric view of the world.

More than 90 percent of the world’s population lives in the heat-threatened temperate and tropicals between 60 degrees north latitude and 60 degrees south latitude with a full 80 percent squeezed in between 20 degrees and 60 degrees north. Fairbanks, Alaska’s second-largest city, is at almost 65 degrees north, and even there some complain about the heat in summer.

Farther to the south, heat killed a reported 112 people in Washington state this year. It sits around 47 degrees north latitude. KUOW radio in Seattle reported the deaths made a June 25 to July 7 heatwave “the state’s deadliest weather-related disaster.”

Across Western North America, that heatwave is believed to have killed more than 1,400 people, about half of them north of the U.S.-Canada border in normally wet and soggy British Columbia. 

Cold zones

Most humans have good reasons to fear rising global temperatures that increase the odds of heatwaves. but not all people have reason to fear. The Russians envision big gains in their wheat production as the planet warms.

“Though wheat only makes up for 2.3 percent of Russia’s total exports (at this time), that constitutes a major proportion of the global wheat export market,” The National Interest reported last year. “Russia is the world’s largest wheat exporter and is expected to control 20 percent of grain export markets by 2028. Climate change is likely to make Russia an even greater global grain power.

“Russian control of such a large portion of the global grain market is not a recipe for food supply stability.”

But surely the Russians, who say they are trying to combat climate change but act like they aren’t, certainly wouldn’t complain about controlling more of the grain market.

Just as Alaska, which regularly vias with Russia for the distinction of being the leader in “wild-caught salmon” no matter how many originate in hatcheries, wouldn’t complain about gaining even more salmon production.

And when it comes to this possible boom for the 49th state, the Nature Communications study puts the spotlight on the Malaspina Forelands, a wild and heavily glaciated stretch of the Gulf of Alaska located generally between the remote communities of Cordova and Yakutat.

Most of the area is within the Wrangell-St. Elias National Park and Preserve and, as of this writing, buried beneath ice.

Glaciers, glaciers and more glaciers

“Greater than 90 percent of coastal (Wrangell-St. Elias) is covered by glaciers and icefields,” according to the National Park Service, and “the Malaspina Glacier, which is the largest glacier along the coastline, is approximately the same size as the state of Rhode Island and, with an area of approximately 5,000 square kilometers (1,931 square miles) contains the largest piedmont lobe of any temperate glacier (in the world),” the agency notes.

University of Alaska researchers last year reported that “the rapidly melting Malaspina Glacier…could create a new ocean bay, one feature in what may be the largest landscape transformation underway in the United States.”

Piedmont glaciers are those that flow out of the mountains onto the plains. The best known are the ice sheets that overflowed the North American Midwest during the Wisconsin Age from 75,000 to 11,000 years ago.

Because the Malaspina Glacier is almost flat, near sea level and unable to retreat from underlaying water that speeds its decay, university researchers reported it is thinning at the rate of several yards per year.

Its eventual disintegration, according to the new fisheries paper, would likely be a boon for salmon.

Salmon colonization of newly deglaciated valleys was long ago documented. Though it is generally believed all salmon return to the streams of their birth to spawn, the scientific reality is that significant numbers regularly stray in search of better, or at least different, spawning opportunities.

The new study ranks the accessibility of future habitat on likely stream gradients after the retreat of the glaciers. Once open water appears, spawning strays are expected to “rapidly colonize, and expand into new habitats…(but) rates of salmon population expansion in new streams can vary depending on the size and distance to source populations.”

The study offers no specific timelines on full colonization.

“River habitat evolution, such as channel stabilization and decreased turbidity, can also take additional time in order for newly accessible and appropriate salmon habitat to become more productive for salmon,” it says. “Thus, although our study reveals the magnitude of future gains in salmon habitat, the processes of habitat creation, salmon colonization, and salmon population expansion are not deterministic and will be highly influenced by local geologic and climatological processes.”

Specific increases in salmon numbers are even harder to predict, the study adds, “because glacier retreat is only one consequence of anthropogenic climate change; the realized effects of glacier retreat on Pacific salmon populations will depend on interactions with other climate-induced stressors such as ocean heat waves, ocean acidification, sea-level rise, and its effect on coastal habitats, warming air temperature, and extreme flood events or droughts, all of which could cause widespread declines in salmon abundance.”

The interactions between environmental changes and salmon are complicated.

Warming to date appears to have been a big plus for sockeye salmon in Alaska’s Bristol Bay, which has seen record runs, and for pink salmon, but looks to have led to or exacerbated declines in production in the Gulf of Alaska south along the coast to the state of Oregon

“…Predicting future shifts in the distribution of productive salmon habitat remains a challenge,” the new study concludes, “and there are no regional projections for the creation of new salmon habitat in response to retreating glaciers. Forecasting the location of emerging salmon habitat is imperative because, while declining glacier ice can present local opportunities for salmon, it is also creating new prospects for large-scale resource extraction industries such as mining, which have the potential to degrade these salmon habitat frontiers. Understanding the timing and location of emerging salmon habitat frontiers throughout the Pacific Mountain ranges of western North America can inform forward-looking management decision-making and conservation planning.”

The Malaspina area has already been the sight of extraction industries. It boasted Alaska’s first oil production and is still thought to have some potential for future oil development.

“In September 1902, the Alaska Development Company, also known as the English Co., discovered commercial quantities of oil at Katalla,” just to the west of the Malaspina, according to the Alaska Department of Natural Resources. “The New York Times reported the discovery of oil at Katalla, and inaccurately stated that the English Co. had struck a gusher of oil spewing 200 feet into the air.

“With word of the discovery in the national news, the population of Katalla
expanded to 5,000 people by 1908. Between 1902 and 1931, there were 28 oil wells drilled in the Katalla oil field and 44 wells drilled in the area. Initially, oil was stored in pits dug into the ground; storage tanks were constructed subsequently.

“In total, 154,000 barrels of oil were produced and refined in a small refinery that was completed in 1911 at the Katalla oil field until it burned down in 1933. The refinery was never rebuilt, and people began leaving the area. Katalla’s post office closed in 1943 as the area became a ghost town.”

Since then the area has gone largely back to nature as have other large parts of Alaska once home to extraction industries, but the salmon have remained and the state now regularly produces 200 million fish harvests no one could have dreamed of in the early to mid 1`900s.