Five years after a mass of warm water called “the blob” formed in the northern Pacific Ocean, a similar expanse of warm water is taking shape and could again pose threats to marine life including Skagit River salmon.

National Oceanic and Atmospheric Administration scientists announced Thursday that a new mass of warm water has been forming over the past several months. The news release says the warm water, about 5 degrees warmer than normal, extends from Alaska to California.

They are calling it a marine heat wave.

It has developed similarly and is similar in size to “the blob” of 2014-2015.

NOAA scientists said during a conference call Thursday that it’s difficult to say whether marine heat waves are tied to climate change, but that in general marine waters are heating up as global temperatures warm.

NOAA Fisheries research oceanographer Andrew Leising said the agency started watching for the possibility of a marine heat wave after seeing some warm water off the coast of Alaska in October 2018. Warm water in that area about five years ago was an early sign of “the blob.”

Leising said the current marine heat wave could fade before having severe impacts, or it could continue to grow and exceed the impacts of “the blob.”

“If it keeps going as it is, I would expect it would rival that event,” he said.

Following “the blob,” Skagit River salmon returned in low numbers and with fish smaller in size in early 2016, and fishing seasons that year were restricted and contentious.

The poor returns and size of the fish was likely, according to NOAA, in part because the warmer water in the Pacific meant less food was available to salmon in the ocean.

Chris Harvey, a research fisheries biologist at NOAA’s Northwest Fisheries Science Center, said the concern is that will happen again along the length of the West Coast.

“We expect that a lot of the fisheries that support coastal communities and provide seafood for the U.S. and for parts of the rest of the world (could be impacted),” he said.

Leising agreed.

“These heat waves are changing the marine food chain for salmon and their predators,” he said. “If it persists, it will very likely have impacts on salmon growth and survival rates.”

Those impacts would be to young salmon expected to return in 2020 and 2021.

While much of the focus is on how salmon may be impacted, marine heat waves such as “the blob” have other impacts on marine life and water quality as well.

Following “the blob,” Puget Sound reached record high temperatures in July 2015 and the largest harmful algae bloom recorded in Washington’s waters hit the coast.

“Given the magnitude of what we saw last time, we want to know if this evolves on a similar path,” Harvey said in the release.

NOAA said its regional fisheries science centers are monitoring the situation and will report to fisheries managers how salmon and other species may be impacted.

“We will continue to inform the public about how the heat wave is evolving, and what we might anticipate based on experience (with “the blob”),” Cisco Werner, NOAA Fisheries director of scientific programs and chief science advisor, said in the release.

— Reporter Kimberly Cauvel: 360-416-2199, kcauvel@skagitpublishing.com, Twitter: @Kimberly_SVH, Facebook.com/bykimberlycauvel

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