From Hakai Magazine:
Will different salmon species adapt before the climate votes them off the island?
On a small, grassy point overlooking the lower Fraser River in southwestern British Columbia, a lone angler reels in his line. He checks his lure and gazes out over the broad ribbon of silty water flowing to the sea. Then he casts again. It’s a late August afternoon, and I’m traveling by boat with biologist Dave Scott through the estuary of what is considered one of the world’s greatest salmon rivers. But for the moment, there’s a stillness stretching over the water: the only disturbance is a trail of wakes our boat leaves behind. As we push downstream, I look back at the lone angler perched on the bank. Shoulders slouched, he stands at the water’s edge, line cast, waiting. But the river seems in no hurry to reward his patience.
Salmon tend to be few and far between here in the late summer season, but Scott, a salmon biologist with the Raincoast Conservation Foundation in British Columbia, also knows these are hard times on the river. Many of the Fraser’s wild salmon populations are in serious trouble, with steadily declining numbers, and Scott and his colleagues have embarked on a new project in the estuary to improve the survival of juvenile salmon. A few days ago, he invited me out on the water to see their progress. Earlier this afternoon, Scott, a lanky, outdoorsy, West-Coast millennial in a black T-shirt and forest-green cargo shorts, welcomed me and a photographer aboard a small motorboat in the historic harbor of Steveston, and the three of us set off.
Perched on the bank of the lower Fraser River, the village of Steveston is now a quiet suburb of Vancouver. But during the early 1900s, canneries crowded the Steveston waterfront, where they packed Fraser River salmon into tins that were shipped around the world. The village boomed, and locals took to calling it Salmonopolis. Now times have changed, and few people call it Salmonopolis anymore. Today, much of the fishing talk in Steveston is about conserving and protecting the Fraser’s dwindling salmon stocks.
As we cruise downstream, Scott gives me a short primer on the Fraser estuary. Each year, he explains, five species of Pacific salmon travel through the waters of the estuary. They have specific streams they call home, specific times they migrate out to sea, and specific routes to get there. In other words, most salmon are finicky, so habitats that all five species use are of great importance. The Fraser River estuary is just such a place.
Before the arrival of European settlers, the estuary was a maze of water channels, sandflats, eelgrass beds, and marshlands. It served as a rest area and nursery for vast numbers of migrating juvenile salmon. But those numbers fell as the marshlands were drained for farms and housing developments, and stone jetties blocked water channels to some of the surviving wetlands. So Scott and his colleagues are looking for ways to give young salmon more access to the estuary’s remaining wetlands. They’re also trying to educate the public about the estuary and its critical importance to dwindling salmon stocks. “We’re trying to hit it on all angles,” Scott says, his brown hair tousled by the breeze.
But the Fraser isn’t the only salmon river in trouble. Scientists are also recording worrying declines in wild salmon stocks in other parts of the Pacific Northwest, too. Land development along freshwater habitats is a common problem in the region, but it’s only one of several factors shaping the current picture. Logging, landslides, and climate change also pose serious threats. Rising water temperatures, for example, can impact the intricate food webs that salmon depend upon in both rivers and oceans. And not all salmon species are affected equally, suggesting that genetic diversity within a species also plays an important part in the picture. Remarkably, one of the more genetically diverse and geographically widespread species, chinook salmon, seems to have fared the worst in North America over the past couple of decades.
Given all the changes that salmon populations have seen over the past century, scientists are now looking ahead with a new urgency, bracing for what the future may bring. And many are grappling with several questions. In a future shaped by rapid climate change, which salmon populations will do worse, and which will do better? And how will climate change affect the geographical distribution of salmon in the future? With this information in hand, researchers hope to develop new ways of protecting today’s salmon stocks—and prepare for tomorrow’s.
Much like social scientists, who look at a person’s formative years to understand their behavior and predict how they might act in the future, biologists say they are examining the evolutionary history of salmon as part of the research needed to envision the future of these iconic fish. Where, they ask, did Pacific salmon species evolve, and what experiences shaped their evolution and survival? In other words, what informed their formative years?
In the past, salmon had millennia to adapt to changes. Now we are forcing them to do so again in a matter of decades.
At the University of Washington in Seattle, ecologist Daniel Schindler has given much thought to the question of how salmon evolved and adapted to their local habitats. Over the past 25 years, Schindler has studied populations of Pacific salmon in many ecosystems in western Alaska, examining how they respond to both climate change and land-use issues. On the day we talk over Zoom, Schindler sports a brushy, graying beard after just returning from a four-month field season in western Alaska. As a principal investigator in the Alaska Salmon Program, the ecologist regularly takes graduate and undergraduate students north to monitor juvenile and adult salmon populations and check on how they are faring there. “That’s what keeps me in the business,” he says, one corner of his lips turned upward. “But teaching is fun, too.”....
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Unfortunately one place the pink salmon may survive is in the Atlantic where they are an invasive species after introduction by the Russians:"Alarm bells ringing for Atlantic salmon. An invasive species from the Pacific appears to take its place"
