Cool ocean waters, abundant nutrients provide rosy outlook for Washington salmon

Scientific markers used to predict the health and productivity of marine species such as juvenile salmon were positive in 2021, the second most favorable since 1998, according to analysis from the National Oceanic and Atmospheric Administration (NOAA). Fisheries biologists are cautiously optimistic that those conditions will persist into the near future, supporting the health of juvenile, ocean-run salmon off the coasts of Washington and Oregon.

The report looked at a number of oceanic health markers: atmospheric conditions, water temperature, salinity, oxygen levels, current movement, and biomass of Chinook and Coho salmon, along with food sources such as plankton and small crustaceans. Many of those indicators were more favorable than every year in the last 24, outside of 2008.

“Every once in a while, things are in alignment. … In 2021, everything from water temperatures to phytoplankton, zooplankton, and larval fishes were pointing in the same direction,” Brian Burke, a fishery biologist with NOAA, told MyNorthwest.

Burke attributes those conditions to a strong upwelling in the Pacific along the 45-degree parallel north, a term which refers to atmospheric and ocean conditions that bring cold, nutrient rich water from the deep ocean toward the surface.

“It has a lot of nutrients, so phytoplankton and zooplankton can really thrive because the nutrient base is strong,” Burke added.

Those conditions allow for species such as juvenile Chinook and Coho salmon to thrive while they’re out to sea, close to the surface.

“There’s a lot of food out there,” Burke explained. “For example, one of the primary indicators that we look at is copepod biomass. … In a good year, what we’re looking for is a lot of the larger fattier species, the northern species of copepods. … We see a lot of them up and down the coast, following California. Other researchers have been seen similar things, so it’s looking like a productive year, particularly off [the coast of] Oregon and Washington.”

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Pacific Ocean conditions along the West Coast from Alaska to Mexico were severe in 2014 and 2015 when an extreme warming persisted, upsetting marine life from whales to plankton. The phenomenon would later be dubbed “the blob” by Washington State Climatologist Nick Bond. Ocean temperatures along Washington state and Oregon have since rebounded to more normal temperatures and could persist into the next year, as indicated by the NOAA report.

“There’s reason for optimism,” Burke offered. “Nothing turns on a dime in a system this big. There tends to be what we call autocorrelation from year to year. I would expect 2022 to be good. Whether it’s better than 2021, worse, or closer to the average, I don’t know. But there’s reason to think it’s not going to be like the blob year. Things don’t necessarily shift that quickly.”

As for whether or not those juvenile salmon supported by the upwelling will mature into a robust salmon population (Chinook salmon have progressively declined in the Puget Sound since 1984 according to the Pacific Salmon Commission, and were listed as endangered under the Endangered Species Act in 2005), Burke is less certain, citing counterbalancing factors which prevent a linear relationship of growth between favorable conditions for juvenile salmon and their maturation.

“You get a large number of predators that come into the area,” Burke clarified.

“This is one of the reasons that Washington off the coast of the Columbia River is so productive,” he continued. “That’s one of the reasons whales come here. It’s the reason seabirds come from all over the place, and Sooty Shearwaters come from New Zealand every year to feed off the Columbia River because it’s such a productive place.”

“With a productive year like 2021, it’s great for growth. But does that growth translate into higher survival? Sometimes you get a lot of predators, … then it could actually be a really bad year for salmon survival. In general, yeah, it’s looking great and probably will be good this year, too. But inside a guarantee, certainly not.”

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