BLAINE - A new health threat has been discovered in Whatcom County shellfish. Samples from Semiahmoo Spit reveal unsafe levels of the biotoxin that causes diarrhetic shellfish poisoning, or DSP.

All county beaches have been closed since early July to recreational shellfish harvesting due to high levels of the toxin responsible for paralytic shellfish poisoning.

The DSP samples were the first ever from Whatcom County. The toxin first appeared in the state in July 2011, in Sequim Bay.

Symptoms of DSP include diarrhea and vomiting, and last up to three days. The county Department of Health will continue to monitor shellfish toxicity and report any changes in harvest status.

Call the state shellfish hotline at 1-800-562-5632 before taking shellfish for consumption from state beaches.

Shellfish available in stores and restaurants are tested for biotoxins before going to market.

Reach RALPH SCHWARTZ at ralph.schwartz@bellinghamherald.com or call 360-715-2266.