Paralytic Shellfish Poisoning (PSP) levels are rising above safe levels in Central Puget Sound

Paralytic Shellfish Poisoning (PSP) levels are rising above safe levels in Central Puget Sound. The state Department of Health urges recreational shellfish harvesters to check the department’s biotoxin hotline before they harvest.

Currently, all of King County is closed to all shellfish harvest. Large portions of Kitsap, Pierce, and Snohomish counties are also closed. The closure is only for recreational harvest at this time. Commercially harvested shellfish currently on the market have undergone thorough testing and are safe to eat.

Commonly called "Red Tide," PSP concentrations have reached significant levels in areas of the Central Sound. PSP levels can rise rapidly, and the public should not harvest shellfish from closed beaches. Mussels are the first species to concentrate the toxin in their tissue, and the health department cautions harvesters to especially avoid recreationally harvested mussels from these areas.

"We know that levels of PSP can increase to lethal levels in a very short time," said Frank Cox, biotoxin expert for the department. "We cannot predict where or when levels will become more dangerous. This is one of the reasons PSP is such a health risk."

PSP is generally more prevalent in summer months but can be present any time of the year. Tiny algae that grow in Puget Sound cause PSP. Shellfish eat the algae and concentrate the toxin in their tissues. Health officials believe that they are just seeing the beginning of the current "algae bloom" in Central Sound and expect to see toxin levels rise even higher over the next few weeks.

"Anyone who has recently harvested shellfish such as clams, oysters, cockles and mussels from these areas should not eat them," says Cox. "PSP can be deadly. If you have harvested shellfish from a closed area, the best thing to do is throw them out immediately."

A person who eats shellfish contaminated with PSP can become ill within minutes of eating. Symptoms of PSP include numbness and tingling of the lips, tongue, fingers and other extremities. In high doses it can cause difficulty swallowing and may lead to paralysis of the respiratory system, which can cause death without emergency life support. A person who suspects they have eaten contaminated shellfish should seek medical help immediately.

In August 2000, nine people became ill after eating mussels recreationally harvested from Pierce County’s Carr Inlet; five of the nine people required hospitalization. Cooking or freezing does not destroy the toxin. Shellfish containing the toxin do not look or taste any different than shellfish that are not contaminated. A laboratory test is the only way to tell if the toxin is present.

Harvesters should look for and obey warning signs that have been posted on many recreational beaches. However, there are miles of public and private shoreline that have not been posted.

The hotline — 1-800-562-5632 — and the Marine Biotoxin Web site.


  1. Elegbeleye Owoyemi Wahab Elegbeleye Owoyemi Wahab Nigeria says:

    There is need for extensive (global) studies on paralytic shellfish poisoning!

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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