Fickle ocean patterns influencing salmon, steelhead returns
A member of a research crew prepares to deploy a net that catches copepods as part of an ocean condition sampling project.
Whether it’s good, bad or middling, salmon don’t have a choice.
It’s sink or swim, eat or be eaten when smolts hit the ocean. The conditions there can play an outsized role in how many of them survive to adulthood and eventually return to freshwater rivers to spawn.
But the ocean is a big, mysterious place. Parts of it can be great for young fish with plenty to eat and other parts are like food deserts teaming with threats.
On top of that, different species use the ocean differently. Steelhead, for instance, quickly head for the open ocean far off the West Coast.
“They blast across the continental shelf and they keep going out,” said Laurie Weitkamp, a fisheries biologist with the National Oceanic and Atmospheric Administration at Newport, Oregon.
Coho and fall chinook don’t do that. Instead, they make a right turn when they transition from the Columbia River to the ocean and meander north.