A marine heat wave similar to the infamous Blob that disrupted ecosystems, shut down fisheries and hurt salmon runs five years ago has returned to the West Coast.
Scientists are tracking a new expanse of warm water they say is on a trajectory to be as big if not bigger than the 2014 event.
If the heat wave persists, it could take a major toll on key species like salmon.
The heat wave emerged over the past few months, formed in part by a ridge of high pressure that dampened winds that would otherwise mix and cool the ocean’s surface. However, the heat wave could break up rapidly if the weather patterns that caused it change, according to Nate Mantua, a research scientist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center.
Ocean conditions had yet to return to normal following the Blob. Biologists aren’t sure yet what the full effects of this new heat wave will be but, given its size, they say it has likely already started to impact marine ecosystems.
Commercial and sport fisheries have noted poor landings off Washington state and Oregon this year, Mantua said.
The conditions created by the Blob resulted in one of the largest harmful algal blooms ever recorded on the West Coast. Domoic acid, a naturally occurring marine toxin, shut down crab and shellfish fisheries. Multiple fishery disasters were declared and thousands of young California sea lions were stranded on beaches. Salmon entering the ocean endured unusually bleak conditions and returned in low numbers to freshwater habitats.
Researchers have even drawn a connection between higher numbers of whales tangling with fishing gear. In response to temperature and forage conditions, the large mammals shifted into areas where they were more likely to tangle with gear, said Chris Harvey, a research fisheries biologist with NOAA’s Northwest Fisheries Science Center.
“We had a lot of expectations about how things would respond,” Harvey said about the years following the Blob’s appearance. “Some of them were correct and some were not at all correct and then we got a lot of surprises.”
Researchers are working with a sample size of one, he noted. After the Blob, this new warm water expanse is the second largest marine heat wave in terms of area in the northern Pacific Ocean in the past 40 years, according to researchers.
“And since we only have a sample size of one we should expect there to be some surprises we currently can’t anticipate if this event persists (for several years),” Harvey said.
But while the Blob caught many people by surprise in 2014 — no one was quite sure what they were looking at as it formed and then persisted — researchers were more familiar with the signs this time around.
They may not be able to completely predict what will happen, but agencies have stepped up some monitoring efforts, particularly following the huge harmful algal bloom in 2015.
“We also now have a little bit more of a better understanding of the impacts of that harmful algal bloom in terms of how extensive it was, the duration of fisheries closures that it caused, the socioeconomic impacts to fishing communities,” said Stephanie Moore, research oceanographer with the Northwest Fisheries Science Center.
This knowledge will “help us to get the message out so that those groups can be better prepared in the event that (another bloom) does occur,” she added.
Researchers can’t say with certainty whether the heat wave is directly related to human-caused climate change or if the weather patterns that caused the heat wave and the Blob signal the start of a new normal. But the Blob’s effects did appear to be exacerbated by underlying warming in the ocean linked to climate change, Mantua said.
For now, the question is whether the heat wave will stick around long enough to cause long-reaching problems like the Blob or if a shift in weather patterns will break it up. Forecasts show the heat wave moderating but continuing for months.