The danger of potentially lethal paralytic shellfish poisoning has led to the closure of recreational harvesting of all species of shellfish all along the Strait of Juan de Fuca, including Sequim Bay and Discovery Bay, and beaches on Port Ludlow and Mats Mats Bay.

Shellfish harvesting is OK according to the state Department of Health (DOH) on Oak Bay and Kilisut Harbor including Mystery Bay, with the exception of butter clams and varnish clams. Those two species hold onto toxins longer than others.

High levels of the marine biotoxin that causes paralytic shellfish poisoning (PSP) were found this week in samples of shellfish all along the areas closed to recreational harvesting.

Commercially harvested shellfish are sampled separately, and products on the market are safe to eat, health officials have said.

Closures of North Olympic Peninsula beaches to shellfish harvesting due to PSP are not unusual for this time of year, according to DOH.

Jefferson County Public Health has posted warning signs at public access points in Discovery Bay, Mats Mats Bay and Port Ludlow.

Pacific Ocean beaches are seasonally closed to harvesting of all species of shellfish.

“All species” refers to clams (including geoduck), oysters, mussels and other invertebrates such as moon snails. All areas also are closed to the sport harvest of scallops.

The closure does not apply to shrimp.

Crab meat is not known to contain the biotoxin, but the guts can contain unsafe levels. To be safe, clean crab thoroughly and discard the guts.

PSP can kill. It is caused by eating shellfish contaminated with toxins from the naturally occurring marine plankton Alexandrium.

The biotoxin is not destroyed by cooking or freezing contaminated shellfish.

Symptoms of PSP can appear within minutes or hours and usually begin with tingling lips and tongue, moving to the hands and feet, followed by difficulty breathing and paralysis.

Anyone experiencing such symptoms after consuming shellfish should contact a health care provider immediately.

For extreme reactions, call 911.

In most cases, the algae that contains the toxins cannot be seen and must be detected using laboratory testing.

To find out which areas in Washington are safe to harvest shellfish, check the Shellfish Safety map at www.doh.wa.gov/ShellfishSafety.htm or call the Biotoxin Hotline at 1-800-562-5632.