A new marine heat wave has formed off the West Coast that is similar to "The Blob" that devastated sea life and ravaged runs of Pacific salmon.
Although the similarities are striking, whether the new system will cause the same havoc is yet to be seen.
Like The Blob, which formed in 2014 and peaked in 2015, the new mass of warm water emerged over the course of a few months. A persistent weather pattern has becalmed winds that typically stir up the ocean's surface to keep it cool. The heat wave is relatively new and right now mostly has affected the upper layers of the ocean. If weather patterns shift, it could break up rapidly, according to the National Oceanic and Atmospheric Administration (NOAA).
"It looks bad, but it could also go away pretty quickly," said Nate Mantua, a research scientist at NOAA's Southwest Fisheries Science Center in La Jolla, California, in a news release Thursday.
The Blob upended the West Coast marine ecosystem, resulting in the deaths of millions of animals, from seabirds to sea lions. Salmon runs cratered, adding to the stress on animals that eat them, including endangered southern resident killer whales.
The new expanse of unusually warm water is eerily similar: It has quickly grown in much the same way, in the same area, to almost the same size, stretching from roughly Alaska to California. It is the second-largest marine heat wave in terms of area in the northern Pacific Ocean in the last 40 years, after the earlier Blob.
"It's on a trajectory to be as strong as the prior event," said Andrew Leising, a research scientist at the Southwest Fisheries Science Center. About five years ago, sea temperatures peaked at close to 7 degrees Fahrenheit above average. This year's heat wave already is almost as large and almost as warm, with temperatures as much as 6 degrees Fahrenheit above normal over a very large area. The size and intensity of the heat wave are ominous signs of its potential danger to marine life.
Effects can travel high up the food chain. During The Blob, sea lion mothers had to forage farther from their rookeries in the Channel Islands off Southern California. Hungry pups setting out on their own to feed became stranded.
Last time around there were unexpected outcomes, including much higher stranding rates of gray whales. That was because the whales migrating up the coast encountered crab fishermen out later than usual -- with gear in which the whales became entangled. The crab fishery was delayed because of the largest harmful algae bloom ever recorded on the West Coast in 2015.
The 2015 bloom was detonated by unusually warm water, and shut down crabbing and clamming for months. Multiple fishery disasters were declared.
This time around, Washington is already seeing a widespread harmful algae bloom that could be related to the warm water mass, said Stephanie Moore, research oceanographer for NOAA's Northwest Fisheries Science Center.
The bloom is quite large and poisonous, stretching from the outer coast to the Strait of Juan de Fuca, the San Juan Islands and into Puget Sound. Harvest of any shellfish species from the area — clams, geoducks, scallops, mussels, oysters and other invertebrates such as snails (not crab or shrimp) — is to be avoided, under an advisory from the state Department of Health. Crabs should be very carefully cleaned before eating, Moore said.
There is no risk from contact with the water for people or pets, Moore said. Shellfish are filter feeders and concentrate the poison in their tissues; eating shellfish imbued with the toxin delivers a powerful dose of neurotoxin that induces paralysis and even death. Mussels tested were eight times more toxic than the regulatory limit for safe seafood.
"These are pretty high levels of this toxin that is very dangerous," Moore said. There is no antidote.
The same weather conditions that gave rise to the marine heat wave are stoking the bloom. And the warm water is also helping it grow.
The heat wave also has the potential to shift the ranges of animals, with cold-water species such as salmon going deeper, making them harder to catch, and warm-water species moving into areas where they usually don't thrive. The warm water also concentrates predators, potentially lethal for baby salmon.
The nutritional level of the food available to young salmon entering the ocean this year probably is degraded by the warm water mass. That is bad news for salmon returns years from now -- denting hopes for a turnaround in what now are four years of salmon scarcity.
Federal scientists are continuing to monitor the heat wave. Forecasts now show it moderating, but continuing for months.
"There are definitely concerning implications for the ecosystem," said Nick Bond, a research meteorologist with the Joint Institute for the Study of the Atmosphere and Ocean, a collaboration between NOAA and the University of Washington.
"It's all a matter of how long it lasts and how deep it goes."
The last disturbance spewed heat to a depth of 5o0 meters in the sea and that heat still has not entirely dissipated, said Toby Garfield, director of the Environmental Research Division of the Southern Fisheries Science Center. So far, the heat from this event is only in about the top 50 meters of the ocean.
Some animals never have experienced a normal ocean in their lives: Salmon coming back in such poor numbers now went to sea during the last heat wave, and are coming back as this one started setting up.