Higher Temps, Less Food


Warming waters and reduced food supply off the coasts of the United States and Canada are threatening the North American Atlantic salmon, according to a new study by scientists at the University of Maine and Gulf of Maine Research Institute (GMRI).

“During the last 30 years, salmon populations have declined in a similar manner across six regions of North America,” says the lead author, Katherine Mills, a research associate at UMaine and GMRI. “This pattern points to a broad shift in the ability of salmon to survive in the northwest Atlantic Ocean.”

North American Atlantic salmon spend as many as six years in the freshwater streams where they’re born. They then swim thousands of miles to winter in the Labrador Sea and feed off West Greenland.

In recent years, waters in the Labrador Sea have been getting warmer while salmon’s primary food source, small fish known as capelin, have been diminishing in both size and abundance. Mills’ findings, published in “Global Change Biology,” showed that declines in salmon populations mirrored changes in temperature and food availability.

“The link between salmon declines and ocean warming is troubling, given the rate of warming in the Labrador Sea and near Greenland,” Mills says. “It’s imperative that we learn how climate and other ecosystem factors are influencing the species, so that we can identify opportunities to aid in its recovery.”

Additional collaborators on this research include the Northeast Fisheries Science Center and the University of Arizona.

Contact: Beth Staples, University of Maine, 207.581.3777, beth.staples@maine.edu; Steven Profaizer, Gulf of Maine Research Institute, 207.228.1635; steven@gmri.org