Paralytic shellfish poisoning (PSP)
Documented Alaska PSP fatalities date back to 1799 when the crew of Alexander Baranof of the Russian American Trading Company ate contaminated blue mussels at the now notorious Poison Cove in Southeast Alaska. Since 1973 over 150 PSP outbreaks have been reported. The Alaska Division of Epidemiology estimates there has been a 7-fold increase in PSP events since 1973. In 1997-98, reported PSP illnesses occurred at Southeast Alaska, Kodiak Island, the Alaska Peninsula, and the Aleutian Islands. In 1997, nine cases of illness occurred resulting in one death, and in 2010 PSP cases occurred from Southeast Alaska to the Aleutian Islands with two deaths, notably one was from eating PSP-tainted Dungeness crab.
The Aleutian Pribilof Islands Association (APIA) senior scientist, Bruce Wright reacted to this new twist in PSP toxicity by investigating PSP-tainted Dungeness crab; a paper entitled “Is there a life-threatening risk from PSP in Dungeness crab in Southeast Alaska?” is available at http://environmentalaska.us/psp-in-dungeness-crab.html. The research effort and paper describe the risks associated with consuming PSP-tainted crab and the lack of oversight by Alaska regulatory agencies which put people at risk of poisoning.
In 2012, Wright was informed that several Kittlitz’s murrelets (Brachyramphus brevirostris) died in Kodiak Island nesting sites from consuming PSP containing sandlance (Ammodytes americanus). Sand lance are a nearshore small forage fish that are consumed by many marine predators including several that are species of concerned; endangered Steller sea lions, threatened fur seals, threatened sea otters (up to 12% of their diet can be sand lance), Pacific salmon and many other predators. In 2014 APIA’s Wright is studying PSP in sand lance in the Aleutian Islands.
So far, Wright has found that in 1978 in Massachusetts over 70 Common Terns (Sterna hirundo) and other terns and gulls were killed by PSP. PSP toxin was detected at lethal levels in sandlance, the terns’ principal food (Nisbet 1983). In the Pacific, data from the Coastal Observation and Seabird Survey Team (COASST) project includes unexplained birds mortality events, bird wrecks, that indicate the healthy-looking birds died from a marine toxin event. Elevated PSP has also been found in Alaska marine mammals. Shumway et al. (2003) stated, “the full impact of PSP on marine predators is undetermined and consequences from chance encounters with schools of toxic sand lance should be investigated.” This is the goal of our PSP research.
Sand lance are implicated in obtaining high levels of PSP likely from feeding on the zooplanktons that feed on the organisms that produce the PSP toxins, a marine dinoflagellate, Alexandrium sp. The transfer of the PSP toxin to marine predators may be common along the North Pacific coast and may be impacting marine predator populations. Some of the hypotheses to consider when analyzing the data are:
H1: Marine predator population numbers may fluctuate in response to consumption of PSP-tainted sand lance.
H2: PSP-tainted sand lance occur in the Aleutian Islands marine waters.
H3: PSP levels peak in sand lance in conjunction with the peak of PSP in the environment, in bivalves and Alexandrium sp. blooms.
H4: All large marine predators that feed on sand lance can die from consuming PSP-tainted fish including whales, salmon, seals, birds, sea otters, sea lions, etc.
These hypotheses are discussed in the popular press article at: http://www.alaskadispatch.com/article/20140214/tiny-fish-could-be-blame-crashing-alaska-sea-life-populations
During the 2014 research effort, sand lance will be collected using cast nets, beach seine and digging from the sand from locations currently monitored for PSP in bivalves to determine levels of PSP in the sand lance. This directed sampling will incorporate information from local residents, but the PI has already identified several locations in the Aleutian Islands where sand lance can be collected and areas that usually have elevated PSP levels.
Already Aleutian Island residents are describing incidents of dead and dying sea birds and shoals of dead sand lance. NOAA’s Auke Bay Laboratory researchers have surveyed many of the beaches in the Aleutian Islands; they found sand lance at every sandy beach. The potential for wide spread die-offs from PSP, via PSP-tainted sand lance, appears high.
The APIA PSP research and monitoring project has been collecting PSP data since 2006 near many Aleutian Island communities. The latest data can be found at: http://environmentalaska.us/paralytic-shellfish-poisoning-in-alaska.html.
Protect Yourself From Paralytic Shellfish Poisoning:
There is a way you can protect yourself from PSP poisoning.
I. Don’t Eat Them: The easiest and best way you can protect yourself from PSP poisoning is to not eat bivalves (clams, mussels, scallops, cockles) from Alaska beaches. Shellfish sold at wholesale and retail markets require PSP testing and are considered safe for human consumption.
II. Know the Species: But if you do eat bivalves from Alaska’s beaches you can reduce your risk by avoiding the most dangerous species, butter clams and blue mussels. 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. The official policy of the state of Alaska is that all shellfish that are untested are unsafe to eat. This includes littleneck clams since there have been recorded toxin levels. Littleneck clams are safer than other shellfish, but there is no guarantee they are safe when there is a PSP problem in the area with other species. 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.
Crabs feeding on toxic shellfish can accumulate PSP toxin in their digestive system, so Wright recommends that before cooking, remove the back shell of the crab and clean out all the dark soft tissues that compose the digestive system and crab butter.
III. Practice safe harvest strategy: Catch – Hold – Test
Follow these steps and you will decrease the likelihood of becoming ill from PSP:
1. Identify a beach in the community where a harvest will be scheduled.
2. Notify community members of the harvest location and date.
3. Monitor the beach for toxin levels at least once prior to the harvest date and during the same tide cycle as the harvest by collecting sample(s) of the target species and testing for toxin at the ADEC laboratory (see Appendices A-C). Since this is not a regularly scheduled event and timely notice of results is essential, DEC should be notified in advance of any collection and shipment to be sure the DEC lab has the testing supplies on hand and can provide timely notice. Contact Matthew Forester, Bio-Analysis Section Manager, Department of Environmental Conservation, Environmental Health Lab., Phone: 907.375.8204, Email: Matthew.Forester@Alaska.gov
4. If the samples are acceptable for harvest (less than 80 ug PSP/100 grams of tissue), the community will be notified that the harvest will proceed.
5. The beach boundaries for harvest will be marked, and on the day of harvest, harvesters will be supervised by a selected community representative to assure they are harvesting the correct species and remain within the boundary of the harvest.
6. Harvesters will be instruction to refrigerate and hold their harvest until an official PSP test of the harvest is completed.
7. Sample(s) of shellfish will be taken from the harvest and tested by ADEC laboratory. This should require 24-96 hours.
8. Test results will be delivered to the community and through local broadcast media.
9. Harvesters will be instructed to return the shellfish to the beach if PSP results are unacceptable.
PSP is a public health emergency and should be reported immediately to Alaska Section of Epidemiology by health care providers or citizens. To report, please call 907-269-8000 Mon-Fri 8 AM-5PM, or 1-800-478-0084 after-hours. Early symptoms include tingling of the lips and tongue, which may begin within minutes of eating toxic shellfish or may take an hour or two to develop. Symptoms may progress to tingling of fingers and toes and then loss of control of arms and legs, followed by difficulty in breathing. Some people feel nauseous or experience a sense of floating. If a person consumes enough toxin, muscles of the chest and abdomen become paralyzed, including muscles used for breathing, and the victim can suffocate. Death from PSP has occurred in less than 30 minutes.
For more information, contact the APIA Climate Change – Harmful Algal Bloom Project Manager:
Aleutian Pribilof Islands Association
1131 E. International Airport Rd.
Anchorage, AK 99518-1408