According to study leader Ed Farley, a NOAA Fisheries scientist with the Alaska Fisheries Science Center, the warming climate is increasing freshwater habitat and improving early marine survival of pink salmon in the northern Bering Sea.
These findings are important for commercial and subsistence fisheries, as well as coastal fishing communities now preparing for changes in the future. “Subsistence harvesters would like to know what foods may be available to them now and into the future,” Farley said.
Pink salmon are the most abundant salmon species in the North Pacific Ocean, which encompasses the Chukchi and northern Bering seas. The Pacific Arctic marine ecosystems, like other high latitude regions, is on the forefront of climate change.
Farley notes that while research has been ongoing in the north Bering Sea for about two decades, and sporadically in the high Arctic, that they have seen dramatic changes. “We didn’t expect to see this much loss of sea ice for 20 more years,” he said, “But it is already happening. Seabirds have shifted from fish-eating species to plankton-eating species. Fish such as walleye Pollock and Pacific cod are moving north in large numbers. And we are seeing big changes in salmon populations.”
Residents of coastal areas of the Chukchi and Beaufort seas have noticed for the last decade an increase in pink salmon in their subsistence fish nets. More adult pink salmon are being found in subsistence nets as far east as the Canadian Beaufort region. Farley says it is likely that these adult pink salmon are straying north during this period of warmer summer ocean temperatures.
“What we do not know yet is if the freshwater streams in the high Arctic are warm enough to support successful spawning,” he said. Still it is likely that if warming continues in the high Arctic pink salmon could begin spawning in those freshwater systems.
That forecast begs the question about potential food competition.
Juvenile pink salmon feed on a combination of zooplankton and small fishes. Farley says that how increased abundance in juvenile pink salmon will impact other fishes through potential competitive interaction for food remains an unknown.
“There are a lot of unknowns on competition among fish species in the northern Bering Sea as the recent warming has seen an increase in adult Pacific cod and walleye Pollock into the region too,” he said. At this time it is difficult to speculate on how potential competition among fish species will play out as the shifts in distribution and abundance of fishes in the region are occurring now,” he said.