Alaska shellfish farms temporarily shuttered due to deadly toxin

Published on
July 6, 2017

High levels of paralytic shellfish poison (PSP) have temporarily left some of Alaska’s shellfish and oyster farmers out of commission.

Although the toxin has been previously spotted in areas such as Southeast Alaska, Prince William Sound and Kodiak, the last couple of years have seen PSP and its affects travel to troubling new locales, Kimberly Stryker, program manager for Alaska's Food Safety and Sanitation Program, told Alaska Dispatch News

"This is definitely something that is concerning for us," Stryker told the newspaper. "We are very fortunate to have pristine water in Alaska, but we have a long history with PSP. And it's a scary thing."

Naukati Bay-based Shikat Bay Oysters, on the Prince of Wales Island, is one farm currently navigating higher levels of PSP, which were first recorded in early June 2017. The farm shut down its operations one week later after oysters tested over the limit of 80 micrograms per 100 grams of the toxin, said Abby Twyman, Shikat Bay Oysters' director of operations. The farm remains closed as of July.

As of 30 June, recreational shellfish monitoring firm Southeast Alaska Tribal Ocean Research had pinpointed elevated levels of the toxin in 10 spots in Southeast Alaska, which all have an advisory in place for all shellfish species. Many shellfish farms near to Shikat Bay Oysters have been testing “hot” for PSP since early June, Twyman told Alaska Dispatch News. 

"This is abnormal and we are just trying to get a sense of it, if this is the new reality," Twyman said of the shutdown, which has come during Shikat Bay Oysters’ busiest time of year – summer tourist season – when the farm typically conducts the majority of its sales. 

To continue operations, farms that have tested positive for high levels of PSP will need to produce three consecutive clean samples before they’re cleared to get back to business.  Samples must be taken a minimum of four days apart and species like oysters usually need several weeks to clear the toxin, Stryker said, meaning elongated closures are often experienced by afflicted farms. 

"Alaska seems to be a canary in the coal mine when it comes to these kinds of things," Stryker told Alaska Dispatch News. "We are vigilant and paying attention and trying to draw conclusions — but that takes a lot of research."  

Shikat Bay Oysters is prepared to wait it out as long as it takes, according to Twyman. In the downtime, the company will take inventory and develop new baby oysters. 

"We are hardy Alaska stock and we aren't going to let something like this keep us down," Twyman said. "We are just making a new plan."

A result of the Alexandrium algae bloom producing the saxitoxin chemical, PSP often accumulates in clams and oysters – and, in turn, shellfish-hungry crabs – to a degree that, while harmless for the mollusks, can be dangerous for humans. Eating large amounts of the toxin can potentially result in death for humans less than two hours after consumption, with numbness, difficulty breathing and paralysis also a part of the toxin’s adverse effects.      

In 2016, a clammer had to be hospitalized after coming in contact with PSP, and was placed on ventilators to assist with his breathing. In the 11 years between 1993 and 2014, 117 cases of PSP were recorded by the Alaska Department of Health and Social Services, with four resulting in death. 

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