Local shellfish gatherers are advised to steer clear of the beach near Shoemaker Bay, after specimens tested positive for paralytic shellfish poisoning (PSP).
The alert was posted to the Southeast Alaska Tribal Ocean Research website at http://www.seator.org/data on Monday. A sampling of butterclams collected by the Wrangell Cooperative Association’s Indian Environmental General Assistance Program (IGAP) staff and sent in to Sitka for testing turned out to have more than twice the state’s threshold for saxitoxin, the cause of PSP.
The sample measured at 212 micrograms, above the limit of 80. Saxitoxin is produced by Alexandrium, a genus of phytoplankton which can bloom in large enough groups to taint nearby waters. Being filter-feeders, clams and other bivalves ingest and absorb the toxins from the water, taking months or even years to process them.
IGAP technician Kim Wickman said the offending sample had been collected on August 16. A followup sampling of blue mussels was collected from the same beach on Monday, but were found only to have 54 micrograms of saxitoxin. So far an examination of the water has turned up no algal blooms, suggesting the toxins could have been absorbed from a prior bloom.
“I haven’t seen any Alexandrium,” Wickman said.
When ingested by humans, saxitoxin causes PSP, which is manifested in its first signs by a numbness of the oral membranes. Severe cases can include nausea, vomiting, neurological effects, respiratory failure and ultimately death.
The SEATOR site points out the findings are not certified, and are merely precautionary. With the shellfish collecting season soon coming, it reminds gatherers to exercise caution before eating any finds. Additional information on the different harmful algal blooms and their effects can be found at http://www.seator.org/resources, as well as how to identify different species of bivalve.
“That’s going to be everyone’s best bet,” said Wickman.
This spring the IGAP office began collecting water and tissue samples from local beaches, working through the Southeast Alaska Tribal Toxins network. The SEATT works with 14 different tribal partners, state and federal agencies, and several fishing groups in order to find and identify threats to local food security.
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