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Paralytic Shellfish Poisoning

Posted by on January 23, 2013

While attending law school in the late ’70’s I got a degree in Law and Marine Affairs.  This entailed studying resource management and the Law of the Sea.  We  learned a bit about pollution, fish processing and product safety.

One subject that has become a concern in recent years regards Paralytic Shellfish Poisoning (PSP).  often referred to as “red tide”.  When I was a kid we spent summers cruising in the San Juan Islands and Puget Sound and we never worried about PSP.  In fact, we pretty much dug clams and picked oysters where ever we found them (on public beaches of course).  Those were the days.

PSP concerns should not be confused with contamination from pollution.  Such contamination, often cause by sewage leaks and septic tank drain fields is separate and apart from PSP, and another subject altogether.

Beginning in the 1980’s we all started to hear about “red tide” and hideous stories of people getting PSP and nearly dying.  I think the the most famous account is a story that appears in the annual Wagoneers Cruising Guide.Danger Sign - Shellfish Area CLosed

For a long time I suspected that the scare was an effort to conserve gradually disappearing clams and oysters.  What better way to keep people from digging clams or picking oysters than to tell them they will die?

But the truth seems to be that testing for the toxin has greatly improved (both in scope and quality) and scientists can  detect the toxin at low levels.   Some think it’s due to warmer water and some think it’s due to increased pollution.  I don’t know.  In any event, it is not unusual for entire counties to be closed to shellfish harvesting every summer.  Often the mass closures have exceptions for areas where there are commercial growing operations.  Those operations are required to do frequent testing and those areas are often open for public harvesting.  (For example, Mitchell Bay on San Juan Island.)

In British Columbia vast areas are frequently closed.  Usually the entire area from Queen Charlotte Strait to Alaska is closed   A couple years ago I asked a resource officer about it.  He told me they did not have enough money to test all the beaches in central and north British Columbia so they just close them down. Keep this in mind before you buy an expensive, non-resident British Columbia fishing license.  If all you want to do is dig clams or collect oysters you may find the license to do so isn’t much use due to beach closures and restrictions.

I was told if I wanted to pay to test a particular beach they would do so and then could open it up.  (He said this is the procedure some First Nations groups use to open harvesting in aboriginal areas.)

Regardless  of the reasons for all the PSP closures, I don’t suggest you ignore the warnings or disobey the restrictions.   When a beach or area  is closed, that’s it.  You are not supposed to dig there or pick up oysters, or get scallops, etc.  In some areas, you are allowed to take oysters, but no clams.  In other areas, you can take some clam species but not others.  Often, harvesting butter clams is prohibited because they can be the biggest hazard.   (Butter clams  retain the toxins for long periods of time.)  Crabs are not included in the PSP closures but it is recommended that crabs be cleaned of all visera and guts before cooking.

Cooking shellfish does not make the toxin go away.  Shellfish contaminated with the PSP toxin are just as dangerous after they are cooked.  I have been told that before eating shellfish natives used to rub the raw shellfish on their lips and wait to see if they got a tingling numbness.  (Tingling and numbness are symptoms of PSP poisoning.)  I don’t know if this is true but as a precaution I will often “kiss” my shucked oysters before eating them.  (My wife thinks this is weird.)  Most people think it is best just not to eat shellfish if you are uncertain about safety.

The only way to keep all this straight is to heed the warnings.  Call the hotlines or visit the websites.  Don’t take shellfish from closed areas.

If you like fresh shellfish always check the PSP status.  Washington State Dep’t of Health has a website called Shellfish Safety Information.

The Washington State hotline number is:    1-800-562-5632.

For Canadian information in general visit the Fisheries and Oceans website.  http://www.pac.dfo-mpo.gc.ca/fm-gp/contamination/biotox-eng.htm.

For information about specific fishery areas, go here:  http://www-ops2.pac.dfo-mpo.gc.ca/xnet/content/fns/index.cfm?pg=view_notice&lang=en&ID=recreational&ispsp=1 

Caution:  The Canadians have made it very complicated to figure out what is permitted and what is closed.  The website has a long list of closed areas, with sub-areas and various species exemptions.  You really have to study the list and it’s is impossible to remember so you must print the copy and keep it with you.  Then, just to be sure, you need to check the webpage to get updates.  This can be difficult when you are on a boat with no internet connection so usually it’s best to call by phone.   In British Columbia, you can call 1-866-431-3474.

My best advice is if you like to eat oysters or clams, check the PSP status before you depart and then behave accordingly.  A Washington State shellfish license is cheap and since crab are abundant and exempt from PSP closures it’s usually worth buying the license just to get some crab.  In British Columbia it’s a different story.

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