Elevated toxin levels found in shellfish at City Park and Shoemaker

Wrangell Cooperative Association’s most recent test for paralytic shellfish toxins in blue mussels at two sites in town showed unhealthy levels.

“Paralytic shellfish toxins (PST) levels are above the FDA regulatory limit. … PSTs cause paralytic shellfish poisoning (PSP), and eating wild shellfish from these sites may increase the risk of PSP,” WCA published in a report May 17 after tests from shellfish at City Park and Shoemaker helipad came back with elevated levels of toxins.

The toxins are caused by Alexandrium, a type of phytoplankton. When Alexandrium multiply quickly, or bloom, the shellfish that feed on the plankton can become contaminated. Cooking or freezing contaminated shellfish does not make them safe to eat.

According to Southeast Alaska Tribal Ocean Research, the toxins can temporarily paralyze a person, even causing death in serious cases by making it impossible to breathe. Early symptoms include numbness and tingling in the lips and fingertips.

Symptoms can develop either immediately or several hours after consuming contaminated shellfish. With medical care, patients with PSP can recover fully in hours or days.

WCA typically collects blue mussels for testing every two weeks, said Kim Wickman, WCA Earth Branch tech. The Sitka Tribe of Alaska conducts the testing and it usually takes about a week to get results back.

Since the most recent test showed elevated levels of toxins, WCA will test weekly until they have three tests in a row with safe levels. They will then collect butter clams and cockles for testing as well, as those species tend to hold on to toxins longer, Wickman said. Butter clams can hold PST toxins for two to four years, she added.

The phytoplankton blooms that cause the toxins typically last about a week, but can be unpredictable, Wickman said, adding that although they usually occur during warmer months, they can happen any time of year.

To ensure safe consumption of shellfish, Wickman said individuals should collect shellfish from City Park or the Shoemaker helipad, the same sites WCA tests, around the same time WCA collects. Individuals should process and freeze the shellfish and wait to eat any until tests come back clear. If the tests come back with elevated levels, Wickman said people should dispose of the shellfish.

Individuals can also contact WCA to arrange for testing of their shellfish.


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