NOAA Fisheries’ Northwest Fisheries Science Center in Seattle has mobilized extra scientists to join a fisheries survey along the West Coast to chart an extensive harmful algal bloom (HAB) that spans much of the West Coast and has triggered numerous closures of important shellfish fisheries in Washington, Oregon and California.
HAB stretches from the Central California Coast north to Washington and possibly Alaska, and involves some of the highest concentrations of the natural toxin domoic acid ever observed in Monterey Bay and off the Central Oregon Coast, NOAA reports.
In early June elevated toxin levels led shellfish managers to close the southern Washington Coast to Dungeness crab fishing, the largest-ever closure of Washington’s multi-million-dollar crab fishery.
“We’re taking advantage of our active surveys to focus research on a serious concern for coastal communities and the seafood industry,” said Eileen Sobeck, assistant administrator for NOAA fisheries.
“The better we understand what’s happening out on the water, the better we can address the impacts.”
While localized blooms of marine algae that naturally produce domoic acid are common in spring, the bloom that began earlier this year has grown into the largest and most severe in more than a decade.
Sardines, anchovy and other fish that feed on the algae and other microorganisms known as plankton can accumulate the toxin, in turn poisoning birds and sea lions that feed on them.
“This is unprecedented in terms of the extent and magnitude of this harmful algal bloom and the warm water conditions we’re seeing offshore,” said Vera Trainer, manager of the Marine Microbes and Toxins Program at the Northwest Fisheries Science Center (NWFSC) in Seattle.
“Whether they’re related we can’t really say yet, but this survey gives us the opportunity to put these pieces together.”
Eastern Pacific Chlorophyll-A concentrations as measured by NASA's Terra and Aqua (MODIS) on June 15, 2015. Note: Chlorophyll-A does not necessarily mean HAB, it can indicate both HAB and Non-HAB. Image credit: NASA Aqua&Terra/MODIS. Acquired: June 15, 2015.
State agencies monitor toxin levels closely and impose harvest closures where necessary to ensure that all commercial seafood remains safe to eat.
NOAA Fisheries and others are also developing advanced robotic systems and models to better detect and forecast harmful algal blooms.
Research during previous harmful algal blooms found “hot spots” of toxin-producing organisms along the West Coast, Trainer said, and this year's survey will search for similar concentrations.
Concentrations of domoic acid at hot spots along the West Coast during 1998 harmful algal bloom. NOAA Fisheries is seeking to measure the hotspots again this year. Image credit: NOAA.
The Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) Research Program is completing a study of one such hot spot in California’s Monterey Bay and provides funding for UC Santa Cruz to analyze samples that will be collected during the survey.
The results will help investigate connections between the current bloom and unusually warm ocean temperatures that have dominated the West Coast since last year, which may offer a preview of ocean conditions likely to become more common with climate changem NOAA says.
California officials have warned against consuming recreationally harvested mussels and clams, commercially or recreationally caught anchovy and sardines, or the internal organs of commercially or recreationally caught crab taken from Monterey and Santa Cruz counties.
Officials in Oregon have halted all shellfish harvesting from the Columbia River south to Tillamook Head and closed the entire state coastline to razor clamming because of elevated levels of domoic acid. High levels of PSTs have led to the closure of mussel harvesting along the Oregon Coast north of Gold Beach. All coastal Washington beaches have also been closed to razor clamming, at an estimated loss of more than $9 million in revenue for coastal communities in the last month alone.
Featured image: This aerial photo shows the 2010 algal bloom on the St. Johns River, south of Buckman. Photo By Jerry Pinto, JU Marine Science Research Institute.