Ocean conditions off most of the U.S. West Coast are returning roughly to average after an extreme marine heat wave from about 2014 to 2016 disrupted California’s ecosystem, but some warm waters remain off the Pacific Northwest, according to NOAA Fisheries.
The warm water has shifted many species beyond their traditional range, according to a new report from the National Oceanic and Atmospheric Administration Fisheries’ two marine West Coast laboratories.
“The report gives us an important glimpse at what the science is saying about the species and resources that we manage and rely on in terms of our West Coast economy,” said council chair Phil Anderson in a statement. “The point is that we want to be as informed as we can be when we make decisions that affect those species, and this report helps us do that.”
Unusually warm ocean temperatures, referred to as “the Blob,” encompassed much of the West Coast beginning about 2014, combining with an especially strong El Niño pattern in 2015.
Severe low-oxygen conditions in the ocean water spanned the Oregon Coast from July to September 2017, causing die-offs of crabs and other species.
Even as the effects of the Blob and El Niño dissipate, the central and southern parts of the West Coast face low snow pack and potential drought in 2018 that could put salmon at continued risk as they migrate back up rivers to spawn.
While the cooling conditions off the West Coast began to support more cold-water plankton rich in the fatty acids that salmon need to grow, salmon may need more time to show the benefits, the report said. Juvenile salmon sampled off the Northwest Coast in 2017 were especially small and scarce, suggesting that poor feeding conditions off the Columbia River Estuary may be lingering.
Juvenile salmon that enter the ocean this year amid the gradually improving conditions will not return from the ocean to spawn in the Columbia and other rivers for another two years or more, so fishermen should not expect adult salmon numbers to improve much until then.
“Overall we’re seeing some positive signs, as the ocean returns to a cooler and generally more productive state,” said Toby Garfield, a research scientist and acting director of the Southwest Fisheries Science Center. “We’re fortunate that we have the data from previous years to help us understand what the trends are, and how that matters to West Coast fishermen and communities.”