New Forecast to Alert Area Officials to Toxic Alga
The goal of one project is to develop a forecasting ability to identify which areas of Puget Sound are at risk of experiencing blooms of the toxic dinoflagellate Alexandrium catenella, which produces potent neurotoxins that accumulate in shellfish. Paralytic shellfish poisoning, a potentially fatal illness contracted by humans when they consume shellfish contaminated by the toxins, frequently forces harvesting closures of productive shellfisheries in Puget Sound.
Similar to an annual hurricane season prediction, this forecast will provide seasonal predictions of the severity and location of toxic blooms – allowing public health and fisheries managers to plan and implement mitigation measures. It is based on annual surveys of seed-like Alexandrium cysts in sediments. The cysts form in autumn and sink to the bottom; blooms start the next spring when the cysts hatch. Cyst maps will be combined with information about the environmental conditions leading to cyst hatching and cell growth and models of water movements in Puget Sound.
“This kind of advanced warning will allow us to make proactive decisions to protect public health and make better use of resources,” said Frank Cox, biotoxin expert with the Washington State Department of Health. “If fisheries managers know that the coming year is going to be “bad” for toxic events, they can choose to harvest earlier in the year before the bloom season begins to minimize economic losses associated with shellfish closures.”
Mobile Lab to Investigate Key Driver in Fish-Killing Alga
The goal of a second project is to better understand the harmful alga Heterosigma akashiwo by building a laboratory that can be quickly mobilized to the coast when sightings occur. Catching this microalga in its most active stages will allow researchers to examine what triggers the cells’ toxicity.
Heterosigma has killed millions of aquaculture fish in Puget Sound since 1989, and has recently been implicated in the decline of a major natural salmon run. Currently, scientists do not fully understand the nature of the toxin, the mechanism by which it kills fish with no apparent impact on other animals and humans, and the environmental factors which control its toxicity.
“Catching this alga in its most active stages may unlock the clues to what turns this species toxic,” said Vera Trainer, project lead and oceanographer at NOAA’s Northwest Fisheries Science Center.
“This mobile lab will provide us with a capability we’ve never had before, and may be key to ensuring safe and economically secure finfish production in Puget Sound and other regions threatened by this harmful organism.”
Research for both projects will be carried out by the NOAA’s Northwest Fisheries Science Center (NWFSC) and their research partners at the University of Washington, the Romberg Tiburon Center at San Francisco State University, the University of Maine, the University of Western Ontario, Canada, Rensel Associates Aquatic Sciences and Woods Hole Oceanographic Institute.
Support for these projects is provided through the NOAA Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) Program, which strives to understand the causes and impacts of HABs in order to predict their occurrence and minimize their impacts. The ECOHAB programme was first authorised by the Harmful Algal Bloom and Hypoxia Research and Control Act in 1998.