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Toxic Algal Bloom Spurred by Pacific 'Warm Blob' Wreaks Havoc for West Coast Crab Fishermen

By By Kevin Byrne, Staff Writer
November 25, 2015, 6:48:52 AM EST

A record-setting toxic algal bloom off the West Coast of North America, that has impacted marine life and fisheries since the spring, has delayed the start of California’s commercial Dungeness crab season.

On Nov. 3, The California Department of Public Health (CDPH) advised consumers not to eat Dungeness and Rock crabs that were caught in waters between the Oregon border and the southern Santa Barbara County line after dangerous levels of toxins produced by the algae were discovered in the shellfish.

"Recent test results have shown persistently high levels of domoic acid in Dungeness crab and Rock crab, which have been caught along the California coastline. The levels have exceeded the state’s action level for the crabs’ body meat as well as the viscera, commonly referred to as crab butter, and therefore pose a significant risk to the public if they are consumed," the CDPH said.


Following the health advisory, the California Department of Fish and Wildlife (CDFW) announced that both the commercial and recreational Dungeness crab seasons were delayed. The commercial season was scheduled to begin Nov. 15 while the recreational season was slated to open on Nov. 7.

"Crab is an important part of California’s culture and economy, and I did not make this decision lightly," CDFW Director Charlton H. Bonham said in a statement. "But doing everything we can to limit the risk to public health has to take precedence."

It is unclear when fishing can resume. The CDFW said they will continue to work with the CDPH to continue to test the crabs to determine when the fisheries can open safely.

"We need colder water temperatures to abate the algae bloom, then the [Dungeness] crabs will have to metabolize the domoic acid," said Jordan Traverso, a spokesperson for the CDFW, told AccuWeather. "It's all really in the hands of Mother Nature."

The size and duration of the bloom, which extends from Alaska to Southern California, has been attributed to the 'warm blob' in the Pacific, where water temperatures have been above normal. Algal blooms along the West coast are not uncommon, but they typically have dissipated by the time the Dungeness season starts.

Similar rules are now in effect in Oregon and Washington, according to fish and wildlife officials in both states.

AccuWeather Meteorologist Anthony Sagliani said the main contributor to the above-normal temperatures is a positive Pacific Decadal Oscillation (PDO), which is a horseshoe pattern of warmer-than-normal waters along the coast of western North America.

"Right now, water temperatures along the West coast range from about 55 degrees Fahrenheit (13 C) along the Washington and Oregon coast to around 68 F (20 C) in southern California," Sagliani said. "These temperatures are quite similar to what they were earlier this year during the [bloom]. In general, these temperatures continue to average 3-5 F (1-3 C) above normal."

"I would expect temperatures to fall a little bit during the rest of this fall and winter, but on average, they will remain 3-5 degrees above normal most likely," Sagliani said.

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The crab industry generated $170 million from the 2014 Dungeness crab harvest, according to the Associated Press. Commercial crabbers in California earned about $60 million alone in 2014 from Dungeness crab landings, Traverso said, adding that the retail value of the crab meat is much higher.

In addition to Dungeness crab, the CDFW closed its year-round commercial rock crab season. The algal bloom has already closed shellfish fisheries along parts of the Washington and Oregon coasts this year. Currently, Washington's shellfish managers have postponed razor clam digging on the state's ocean beaches, while Oregon has closed recreational razor clam harvests along the entire coast.

Cooking or freezing does not destroy domoic acid in shellfish, several state agencies warned. The CDPH said there have not been any reported illnesses due to this event.

According to the National Oceanic and Atmospheric Administration (NOAA), more than 35 birds and mammals have tested positive for domoic acid from Southern California to the Pacific Northwest, which could indicate widespread impacts of the algal bloom in marine food webs.

"The toxins are commonly present in the food web but this year, with this unprecedented bloom, they’re likely having a bigger impact than ever before,” Kathi Lefebvre, a research biologist at NOAA's Northwest Fisheries Science Center, said in a news release. “Our concern is that there does appear to be a link between warm water and bigger blooms, so what does this tell us about future years with warmer conditions?"

Animals with exposure to the toxin as far north as Washington is a major expansion from what researchers have seen in past events, according to Lefebvre.


Steve Fitz, the owner of Mr. Morgan Fisheries in Half Moon Bay, California, told the AP that he was optimistic that toxin levels will go down soon because crab represents the bulk of annual income for many in the fishing community.

"Needless to say, this is devastating," he said.

The loss of Dungeness crab is "very significant," Traverso said, as it's one of the most heavily fished shellfish, along with lobster, in the state. The season typically runs until June, but for several counties including Del Norte, Humboldt and Mendocino counties, it's the end of July, Traverso stated.

"Dungeness is one of our biggest seasons, and northern Californians have made it a very important part of our holiday routine," Traverso said. "We've replaced the Thanksgiving turkey with crab legs, and the Christmas goose with crab cioppino."

The CDFW is exploring the possibility of extending the season, but the demand is higher earlier in the season due to the holidays, she said.

Have questions, comments, or a story to share? Email Kevin Byrne at, follow him on Twitter at @Accu_Kevin. Follow us @breakingweather, or on Facebook and Google+.

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