Gastrointestinal Parasitism and Mercury in Pacific Walrus

• Main Author: Sweitzer, Danielle N.
• Other Authors: Beechler, Brianna R., Sanders, Justin L., Rothenberg, Sarah E., Oregon State University. Honors College
• Format: Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Chukchi; Chukchi Sea; Alaska; Siberia; walrus*
• Online Access: https://ir.library.oregonstate.edu/concern/honors_college_theses/pc289r103

The Pacific Walrus population that lives within the Chukchi Sea near Alaska and the Russian territory Siberia have traditionally held a diet composed of molluscs and benthic invertebrates, with the main dietary choice being clams or other bivalves. Due to global warming, the availability of stable ice resting surfaces has decreased. Without these ice resting surfaces, it is possible that walrus resort to feeding on species within their diets that are higher in trophic level, resulting in an overall change in their nutrient and parasite intake. The objective of this research is to quantify and categorize the parasites in feces of the Pacific Walrus as well as to quantify and explore links between fecal mercury and parasitic numbers. Correlations between parasite richness and MeHg levels, parasite number and MeHg levels, parasite richness and THg levels, and parasite number and THg levels were all deemed statistically insignificant, likely in part due to low sample sizes. This thesis is a pilot study for further insight into the survival of the Pacific Walrus and with further data collection may provide a link between global warming and a change in walrus health. Key Words: walrus, parasite, mercury, Alaska, microbiome