Story by Sarah Teman
Photo by Eric Anderson
Take a moment to think about a black-and-white animal that lives in the Salish Sea, depends on fish, and is threatened by human activities. Did you think orca, or did a certain marine bird come to mind? For Dr. Eric Anderson, he had birds on the brain.
Anderson, Program Head of the British Columbia Institute of Technology’s Ecological Restoration Program and researcher at Friday Harbor Laboratories, studies animals that are much smaller than the giant, charismatic toothed whales that traverse our inland waters. He studies scoters–specifically, white-winged scoters and surf scoters. Easily mistaken for a puffin, scoters are stocky sea ducks that spend winter and spring in the Salish Sea before migrating north to Canada and Alaska to lay their eggs and raise young. Once a common sight in this region, scoter populations have declined by over 60% in the past 50 years. And just like endangered Southern Resident killer whales, which suffer from three main threats, the decline of scoters can be linked to not one, but multiple human-caused issues.
Some years ago, SeaDoc funded Anderson’s team to investigate the causes of scoter decline. While scoters have a diverse diet that includes bottom-dwelling bivalves, crustaceans, and other invertebrates, occasionally served to them by gray whales on a silver platter, one resource is particularly crucial for scoters: herring eggs. Anderson found that scoters rely on herring spawning events to fatten up before they make their long migration north, stopping over at coastal spawning sites to replenish their energy. “Herring provide a food resource that is perfectly timed to rescue a declining trend in body fat, in order to prepare for spring migration and breeding,” Anderson says. “The not-so-happy news is that status of herring is declining.”
Photo by Joe Evenson
However, the decrease in herring and their highly nutritious eggs is only part of the scoter puzzle. Dr. Marjorie Brooks, Associate Professor in Zoology at Southern Illinois University, joined Anderson to unravel the mystery of this seabird’s decline. Their team identified three elements–cadmium, selenium, and mercury–that, when combined in trace amounts, explained the decline in scoters’ nutritional status by 14 to 27 percent. These contaminants, released into the environment by burning fossil fuels, are what scientists call “sublethal stressors” that rob the birds of energy they would otherwise spend on growth and reproduction, redirecting their resources to cope with the effects of contaminants. “It’s the combined effects from many stressors and contaminants, rather than one single stressor, that has the biggest effect,” Brooks says. “It’s like death by a thousand cuts.”
A third reason for scoter decline may be due to a more sinister, broad scale problem–climate change. Anderson speculates that the effects of climate change on the scoters’ breeding grounds may have serious consequences. Compared to other birds, scoters nest in boreal forests relatively late in the Arctic summer, where warming is happening faster. Higher temperatures can lead to a loss in wetlands by melting the permafrost beneath and evaporating the surface water. Warming can also cause aquatic invertebrates to emerge from their larval stage or temperature-induced torpor earlier in the season than normal, leaving little food for the scoters when they arrive in late summer. “Just like the Southern Resident killer whales, you can’t study these things in isolation–it’s not just food, just contaminants, or just climate change,” Anderson says. “They all overlap. Lots of food available in the winter helps them deal with contaminants, and it might help them deal with food shortages in breeding grounds.”
When it comes to the scoters’ future, both scientists are hopeful. Anderson extols the importance of programs that fund scientific research, like The SeaDoc Society, to understand how ecosystems work and how to best protect them. “Science is an evolving story that incrementally moves us towards the answers,” he says. “Each publication is just another installment that revises our understanding of how the environment works.”
By the same token, Brooks emphasizes the importance of small, daily actions–choosing to bike instead of drive, or using less plastic products–that create a domino effect of positive changes for the health of scoters and the Salish Sea. “You can create an impact just by changing the situation in your own environment,” she says. “Conservation begins with one bird, and one human, at a time.”
Science allows us to understand the underlying causes of declines for at-risk species, which is the first step in reversing them. SeaDoc supporters make our competitive grants program, that funds research like this, possible.