This Sept. 26, 2019 photo shows coastal waters off Greenwood State Beach where The Nature Conservancy is mapping and monitoring one of Mendocino County’s last remaining bull kelp forests near Elk, Calif. (AP Photo/Terry Chea)

Scientists breathe easier as marine heat wave off west coast weakens

Area of exceptionally warm water is substantially smaller now than it was earlier this year

Scientists say a marine heat wave that blanketed a large area of the west coast has weakened, but the potential disruption to ocean life isn’t over yet.

Nate Mantua of the National Oceanic and Atmospheric Administration said the ”good news” is that the area of exceptionally warm water is substantially smaller now than it was earlier this year.

And while the area about 1,500 kilometres offshore between Hawaii and Alaska is still seeing high temperatures by historical standards, it is “simply not nearly as large as it was and it is no longer strong in areas near the west coast,” he said.

Scientists have been watching a marine heat wave that developed around June this year and resembled a phenomenon that was nicknamed ‘The Blob,’ which disrupted ocean life between 2014 and 2016.

The heat wave, which resembles a wedge this time, stretched from south of Vancouver Island to Baja, Calif., and offshore towards Hawaii. It raised temperatures by up to 4 C.

Mantua said “many energetic storms and unusually strong winds from the north off the west coast” have cooled surface waters back to near normal temperatures for much of the region.

“On the other hand, the offshore warming is still in place, and by historical standards, it is still a large marine heat wave,” he said in an email.

The latest climate model forecasts from the National Oceanic and Atmospheric Administration’s Climate Prediction Center suggest that the offshore warming will gradually weaken over the next seven months, but even by spring will still be warmer than normal, Mantua said.

ALSO READ: Students skip school, join climate strikes across B.C.

Prof. Andrew Trites at the University of British Columbia’s Institute for the Oceans and Fisheries said the marine heat wave is caused when there is not enough wind to churn and cool the water.

“This past summer winds were very, very light — not strong enough for ocean to be mixed the way it used to be in the past. As a result the ocean didn’t cool down the way it was supposed to and it’s holding its heat,” he said in a phone interview.

“It’s not that the ocean got warmer, it’s really that the ocean did not get cooler.”

As a result, some species of tropical fish that are usually seen in tropical waters were found off the west coast, he said.

“One of the fish that I saw a lot of this summer was the sunfish and presumably they are here in higher numbers because the water here was unusually warm this summer and they can tolerate warm temperatures,” Trites said.

Mantua said the most obvious impacts included a pattern of unusually low plankton production from July through September from Vancouver Island to northern California.

Warm waters near the coast of northern California, Oregon, and southern Washington brought albacore tuna closer than normal to the coast, and sport fishing was especially good there this summer, he said.

However, ocean salmon fishing in those areas was generally poor, Mantua said.

“All that said, I have not heard of any reported ecosystem impacts in those offshore waters where it remains very warm,” he said.

“I suspect that the extreme warming in the productive part of the open ocean has had some impacts, but there simply isn’t a lot of information coming from those regions aside from satellite observations of ocean colour that tell us some general information about plankton production.”

There is a chance that the marine heat wave might return, Mantua said, although he thinks “the odds for that are low, at least based on the latest climate forecasts.”

Trites said the first time this heat wave occurred about five years ago, it was thought that it would never happen again.

“So this may be an example of climate change and global warming. It is changing the patterns of air circulation and affecting storminess and it’s not going to mix the water the way it used to.”

Hina Alam, The Canadian Press

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

LETTERS TO THE EDITOR: Improved health and social services needed

It’s imperative that the root systemic causes of homelessness are addressed, say letter writers

Province providing financing to help get apartments built in Nanaimo’s Wellington area

120 apartments on Ledgerwood Road intended to be affordable for ‘middle-income’ households

‘Someone knows something’: a look into Vancouver Island missing persons with interactive map

There are more than three dozen people listed as missing throughout Vancouver Island

Regional District of Nanaimo to start delivering new garbage carts

Updated automated curbside collection service set to get underway Oct. 1

Nanaimo RCMP want speeding motorists to ‘slow the blazes down’

Police raise alarm after seeing 400-per cent rise in excessive speeding tickets last month

Islanders want BC Ferries to follow order that lets residents board before tourists

For ferry-dependent communities, ferries are often the sole practical lifeline to work, school or medical appointments.

Departure Bay ferry capacity increases to 70%, says B.C. Ferries

Fifty-per-cent limit being phased out, B.C. Ferries has no current plans to provide masks

Beverly Hills 90210 star’s family selling Vancouver Island Beach Resort

You can own Jason Priestley’s Terrace Beach Resort in Ucluelet for less than $5 million

Outreach team making connections with young people experiencing homelessness in Nanaimo

Nanaimo Aboriginal Centre youth advisory council initiative offers ‘no-barrier’ help downtown

Genetic detectives begin work to trace spread of COVID-19 in Canada

The kinds of genetic technology being used for this project did not exist when SARS hit Canada in 2003

Sports fishers protest Fraser River Chinook closures

Public Fishery Alliance wants hatchery fish open for harvest

Shellfish industry get funds to clean up at Island sites and beyond

Businesses can apply to cover half of costs to clean up so-called ‘ghost gear’

Amber Alert for two Quebec girls cancelled after bodies found

Romy Carpentier, 6, Norah Carpentier, 11, and their father, Martin Carpentier, missing since Wednesday

Most Read