A warm-water ‘blob’ that blanketed the northeast Pacific for two years is finally dispersing, thanks to cold fronts and storms sweeping the Gulf of Alaska.
But even as it appears to fade, scientists say this year’s El Nino effect and future climate change could bring more unusually warm water to the ocean around Haida Gwaii.
Looking at satellite images of the ocean surface, Richard Dewey, an oceanographer and science director for Oceans Network Canada, said storms and cold weather began breaking up the ‘blob’ in mid-November.
“In some sense, it’s exactly what was missing for the last couple of years,” said Dewey.
“We had almost a complete absence of major cold outbreak and storms in the Gulf of Alaska, which is what allowed the ‘blob’ to develop in the first place.”
Beginning in the fall of 2013, the blob spread from offshore Alaska to California — an area larger than B.C. and Alberta combined — with temperatures up to 4 C above normal.
When it blew closer to shore a year later, Haida Gwaii saw record highs off the west coast.
Local fishers have since reported larger blooms of toxic algae — red tides — and more fish that thrive in warm water, including mackerel, which feed on salmon fry and herring.
Researchers found that red sea urchins were spawning early on the Haida Gwaii coast last spring, affecting the traditional Haida fishery.
Ian Perry, a researcher with Fisheries and Oceans Canada, said the main trouble for the salmon fishery is likely to be with the generation of salmon that went to sea last spring and immediately found themselves in warm water.
“It would be as if we had transported them down to California,” said Perry.
“The water is warmer, it’s got the wrong kind of food for them, and it’s got many more predators like mackerel.”
While temperatures generally seem to be cooling back to normal, Perry said it’s too soon to say the blob has disappeared completely.
“We’re not over it yet,” he said. “We’re seeing cooler temperatures at the surface, but down deeper — about 50 to 100 metres or so — we are seeing remnants of this very, very warm water.”
That data comes not from satellites, but from the Argo network — a fleet of underwater robots that drift on ocean currents, descending to depths of about 2,000 metres before they rise back to the surface and relay data on temperature and salt levels.
Moreover, Perry said scientists are still waiting to see if this year’s El Nino effect could bring even more warm water.
“If it comes as strong as it did in the 1990s, it would bring warm water all the way up past Haida Gwaii and into Alaska.”
After reviewing historical ocean data and old weather records, Richard Dewey said there are hints that the northeast Pacific experienced a ‘blob junior’ in 2005, and a similar weather pattern in 1977.
Neither of those events was as strong or as long-lasting as the ‘blob’ that started two years ago, but Dewey said with climate change, the jet-stream shift that led to the blob could occur again.
“We sometimes get lulled into thinking, ‘Oh, climate change is a one- or two-degree change over the next 50 years, who is going to notice that?’” said Dewey.
“What we will notice is if we have major changes to our weather systems that last for years instead of months.”