High PSP Levels in Clams

Observation: The paralytic shellfish poisoning (PSP) results for King Cove, Alaska (butter clams collected 2/6/2014) had PSP toxin levels of 86.8 micrograms/100 grams. The February sample exceeded the FDA limit of 80 micrograms/100 grams. See the data on the attached graph or the Environment Alaska webpage.

PSP levels will likely be different in adjacent beaches and will change with time. Littleneck clams usually do not reach as high of toxicity levels as butter clams and littleneck clam toxicity levels usually drop off quicker than butter clams. If you harvest/consume clams from Alaska beaches you should become familiar with all the clam species. Extreme caution should be taken when consuming any clams, scallops and mussels from Alaska’s beaches. I recommend not eating dead or sick looking forage fish found on Alaska beaches and report these events to me. Forage fish, such as sand lance (sand eels) can become toxic with PSP too.

Shellfish harvesters should be advised that PSP is a serious health risk when consuming personally harvested shellfish. Crabs feeding on toxic mussels, clams or fish (sand lance) can accumulate PSP toxin in their digestive system, so I recommend that before cooking, remove the back shell of the crab and clean out all the dark soft tissues that comprise the digestive system and crab butter. Most shellfish sold at wholesale and retail markets require PSP testing and are considered safe for human consumption, but crabs are not regularly tested for PSP.

The samples for this project are all analyzed by the Alaska Department of Environmental Conservation using approved analytical methods. Note that the FDA limit for PSP is 80 micrograms/100 grams, the red line on the attached graph. The data collection for this project will continue to Fall 2014. Data tables are at Environment Alaska.

Resource:

University of Fairbanks, Marine Advisory Program – Paralytic Shellfish Poisoning: The Alaska Problem, an article in the Alaska's Marine Resources publication. "Written by experts at the University of Alaska Fairbanks and the University of Washington, and medical doctors, this publication is an excellent summary of the PSP problem in Alaska. PST poisoning is caused by neurologically damaging saxitoxins that are byproducts of microscopic algae called dinoflagellates." Ray RaLonde, Professor Emeritus, is the technical editor for this issue of Alaska's Marine Resources. He is the Marine Advisory Program's Aquaculture Specialist. Ray retired from the University of Alaska in October, 2015