Stay Happy as a Clam: Avoid Marine Biotoxins

My parents live on south Whidbey Island, and I spend many summer weekend days enjoying their private beach access (despite the overabundance of driftwood, seaweed and dead crab bits). The beach is also a popular spot for clamming, and I often see people hauling their buckets and shovels along the tide flats. It was no exception this past weekend, even though the Washington State Department of Health closed recreational shellfish harvest in several counties because of dangerous levels of paralytic shellfish poison biotoxin (PSP) found in many areas, which is as horrible as it sounds. It’s commonly called red tide.

My clam digging beach companions likely missed the warning sign posted at the beach. Luckily for them, a kind beachgoer warned everyone she saw with a bucket about the closure. She likely saved quite a few people from a trip to the emergency department since you can get very sick from eating shellfish contaminated with the toxin. Symptoms of PSP can appear within minutes or hours and usually begin with tingling lips and tongue, moving to the hands and feet. This is followed by difficulty breathing and potentially death. Anyone who has eaten shellfish and begins having these symptoms should get medical help immediately.

There will not always be a good Samaritan on the beach to stop you from harvesting potentially deadly shellfish, so keep this information from the Department of Health in mind:

Know Before You Dig!
A Shellfish Closures Bulletin and a toll-free Shellfish Safety Hotline, (800) 562-5632, identifies beaches that are closed to recreational harvest. The closure information is updated whenever changes occur. Always check these resources before harvesting in an area to make sure it is open.

Cooking does not destroy biotoxins
Cooking will kill the algae that produces the toxin, but the toxin itself is not affected by cooking and remains in the shellfish tissue.

There is no antidote for biotoxin poisoning
Victims must wait for the toxins to naturally flush from their body. Life support systems such as respirators and oxygen are used in extreme cases to keep the victim alive and stable.  See this link for more information about poison symptoms of specific types of biotoxins.

Harmful algal blooms don’t always color the water  
An area may be experiencing a massive bloom even though the water appears clear.  A popular misconception surrounds the term “red tide.” This term is commonly associated with PSP toxin, but algal blooms that color the water red are generally harmless to humans.

Species Matters

  •  Mussels accumulate toxins more quickly than other types of shellfish and are a good indicator species, alerting us that levels are on the rise.
  •  Varnish clams accumulate toxin at higher levels than other species. Their proximity to shallow beaches and fresh water sources (and thus potential pollution) are additional reasons to be especially aware of surrounding conditions when harvesting this species.
  •  Varnish clams and butter clams store toxins longer than other species, and can remain toxic for more than a year after a bloom subsides.  For this reason an area can be closed to varnish and butter clam harvest but open for other species.

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