Paralytic Shellfish Poisoning in the Aleutian Islands

Author: Bruce Wright, Senior Scientist, Aleutian Pribilof Islands Association

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 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 describes that research.

In 2012, several Kittlitz’s murrelets died in Kodiak Island nesting sites from consuming PSP containing sandlance. 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 Aleutian Pribilof Islands Association (APIA) began studying PSP in sand lance in the Aleutian Islands (http://www.apiai.org/services/community-services/environmental-programs/paralytic-shellfish-poisoning-psp/).

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

The APIA PSP research and monitoring project has been collecting PSP data since 2006 near many Aleutian Island communities. The data has been useful informing local residents of the risks of eating bivalves collected on some local beaches. The education and outreach of the projects and presentations of PSP data have been valuable in changing people’s behaviors and far fewer people have been sickened by PSP in the Aleut region since the project began. The latest data can be found at: http://environmentalaska.us/paralytic-shellfish-poisoning-in-alaska.html.

Paralytic shellfish poisoning in butter clams for the King Cove Lagoon 2006-2014. Breaks in the data represent breaks in funding and/or sample collections. Data for additional sites found at http://environmentalaska.us/paralytic-shellfish-poisoning-in-alaska.html.

Paralytic shellfish poisoning in butter clams for the King Cove Lagoon 2006-2014. Breaks in the data represent breaks in funding and/or sample collections. Data for additional sites found at http://environmentalaska.us/paralytic-shellfish-poisoning-in-alaska.html.

GunnersCoveReef_Hoffman2009_Hawadax

 

Header photo credit: Brian Hoffman, Hamline University. Gunners Cove, Hawadax. 2009.

 

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