NOAA scientists tracking large marine heat wave that’s raised Oregon coastal temperatures by 7 degrees

 

 

By DANA TIMS/YachatsNews

A large marine heat wave that has developed each of the past four years has scientists watching closely to see how long it lasts and to what extent it could affect the coastal ecosystem and marine life in the coming months.

A recent lessening in ocean upwelling – when winds push surface water offshore and deeper, cooler water rises to fill the gap — has now allowed this year’s heat wave to reach the coast of Oregon and Washington.

“Normal upwelling provides a barrier,” Andrew Leising of NOAA’s Southwest Fisheries Science Center told YachatsNews. “It keeps the coast cool and keeps the heat wave off shore.”

He added, “This year’s heat wave hit the coast two to three weeks ago, and so far it’s a pretty big event.”

Heat waves are concerning to scientists because, among other things, of their ability to cause harmful algal blooms. Such blooms are associated with elevated levels of domoic acid, which have led to coastwide shellfish harvesting closures.

The National Oceanic and Atmospheric Administration maintains a heat wave tracker. It showed that the water temperature on the Stonewall Bank 20 miles west of Newport was 62.8 degrees earlier this week. That’s nearly 7 degrees higher than the August average, according to NOAA.

The agency’s current heat wave forecast indicates the formally named NEP2023A will continue in offshore waters through this summer. There is also the risk of coastal warming next spring, although that remains to be seen, Leising said.

“Last year, it came in earlier than this year, but washed off the coast later,” he said. “Typically, it keeps going back and forth until October or November.”

Heat wave history

 A heat wave of still-historic proportions was initially detected in 2013. Spurred by an El Nino’s warming effects, it eventually grew so warm and so large that it was dubbed “The Blob.”

This mass of water was between 4 and 10 degrees above average and covered more than 1,000 miles between North America and Asia, and was measured to a depth of 300 feet.

Over the course of two years, The Blob dramatically affected everything it touched, including economically valuable fisheries.

Species that rely on cold water, such as salmon, were forced to move to escape the warm water by swimming elsewhere. Populations of forage fish needed by seabirds also dwindled, causing widespread seabird die-offs.

For now, anyway, no one is predicting a similar event, although a developing El Nino could still help bring that about next year.

“We are really watching to see how this thing develops,” Leising said. “Heat waves typically cool in late summer. But add that together with an El Nino in 2024 and it could have a big effect on sea animals next year.”

A sea full of life

 NOAA Fisheries said it is consulting with other agencies and watching for signs of the heat wave’s impacts.

It said various surveys are monitoring the abundance of juvenile groundfish, including rockfish. Science teams are also evaluating the growth of juvenile salmon and steelhead during their first months in the ocean. The warmer waters associated with marine heat waves could slow that growth and reduce their survival during that critical time.

The heat wave could also compress habitat in ways that species and fisheries, such as marine mammals, hake, rockfish, albacore, and salmon, could overlap and lead to bycatch concerns.

Lisa Ballance, who directs Oregon State University’s Marine Mammal Institute in Newport, is getting her own view of the ocean these days as she leads a crew that is meticulously surveying mammals, seabirds and other species in the waters from Astoria to Mendocino, Calif.

“Wow,” she posted Aug. 6 on the institute’s Facebook page. “Just WOW.”

Conditions that day were so extraordinarily calm that Balance reported not seeing a single whitecap.

“Besides the joy of being on the ocean in such conditions, the abundance and diversity of marine megafauna were extraordinary,” she wrote.

She and the crew aboard their vessel, the Pacific Storm, catalogued “86 humpback whales, 25 fin whales, 2 blue whales, a possible sei whale, Dall’s porpoise, Risso’s dolphin, Pacific white-sided dolphin, northern right whale dolphin, and an outrageous look at a group of Baird’s beaked whales.”

In addition to recording 1,985 Fork-tailed Storm Petrels within 300 meters of the boat, Ballance noted one other creature, “a sleepy elephant seal at the surface that drifted down the port side of the vessel.”

The tallying went on with more seabirds.

“There were hundreds of Pink-footed Shearwaters, Sooty Shearwaters, Northern Fulmars, and tens of Black-footed Albatross – all swirling around the surface as far as the eye could see,” Ballance posted, “amidst seemingly a sea of humpback whales while the echo-sounder recorded dense somethings below us.”

• Dana Tims is an Oregon freelance writer who contributes regularly to YachatsNews.com. He can be reached at DanaTims24@gmail.com