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Date of Award

Spring 2023

Document Type

Masters Thesis

Department or Program Affiliation

Marine and Estuarine Science Program of E.S

Degree Name

Master of Science (MS)


Environmental Sciences

First Advisor

Hatch, Marco B. A.

Second Advisor

Peacock, Misty

Third Advisor

Sofield, Ruth M.


Anthropogenic forcing of marine ecosystems is disproportionately impacting Indigenous food systems and the health of coastal Indigenous communities. With increasing harmful algal events, there is rising concern for access and health of coastal communities who rely on shellfish for commercial, food, subsistence, and ceremonial harvest. In the U.S West Coast, the dinoflagellate Alexandrium spp. may produce paralytic shellfish toxins, which can cause shellfish to become toxic and is of especial concern. While recent research has led to greater awareness of the risks associated with paralytic shellfish toxins (PSTs), the concern for harmful algae is not new. Coastal Indigenous communities have long been aware of harmful algae and have relied on traditional ecological knowledge to reduce impacts from harmful algae since time immemorial. In particular, traditional ecological knowledge relevant to the preparation of clams has been used to reduce risk from harmful algae. To analyze paralytic shellfish toxins in butter clams (Saxidomus gigantea), S. gigantea were collected between April 2022-November 2022 in Bellingham Bay, WA. Clams were partitioned into five distinct tissue groups, and enzyme-linked immunosorbent assay (ELISA) was used to quantify paralytic shellfish toxins within the siphon, siphon tip, gills, digestive tract, and rest of body. Results from this study show that the concentration of paralytic shellfish toxins is temporally variable in S. gigantea. We also quantified that the toxin contribution of different tissues varied over the course of two Alexandrium spp. blooms, with disproportionately higher contributions from the siphon, relative to other tissues studied. The selective removal of tissues can significantly reduce exposure to PSTs, however this may not mitigate PSTs completely. The benefit of selectively removing S. gigantea tissues and the cost of sacrificing tissue for consumption to reduce exposure also varied throughout the study period, though discarding the siphon tip, and siphon, and at times the digestive tract commonly showed potential to reduce exposure while optimizing the mass available for consumption.




butter clams, paralytic shellfish poisoning, paralytic shellfish toxins, traditional ecological knowledge


Western Washington University

OCLC Number


Subject – LCSH

Saxidomus giganteus--Pacific Coast (U.S.); Paralytic shellfish poisoning--Pacific Coast (U.S.); Alexandrium--Pacific Coast (U.S.); Traditional ecological knowledge--Pacific Coast (U.S.)

Geographic Coverage

Pacific Coast (U.S.)




masters theses




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