Long surveillance dataset links warmer, more open Arctic waters to higher algal toxin concentrations in marine mammals

Kathy (Warren West program) presented 19 years of toxin surveillance and analysis showing a quantitative relationship between ocean warming, open water area, and harmful algal toxin concentrations in Arctic marine mammals. Using 205 bowhead whale fecal samples and environmental data, the team looked at accumulated heat flux 10–20 days prior to sampling and found that higher accumulated heat and larger open‑water anomalies were associated with higher domoic acid and saxitoxin concentrations and higher yearly prevalence of detectable toxins.

"We show statistically and quantitatively that warmer ocean conditions and more open water area is linked to higher toxin concentrations for both of these harmful algal bloom species in the Bowhead Sea," Kathy said, summarizing model results and violin‑plot prevalence analyses. She explained that saxitoxin was detected in a high proportion of samples across years (never falling below ~45% prevalence in the 19‑year record she presented) and that domoic acid prevalence has varied year to year, occasionally reaching 100% prevalence in the sampled animals.

Kathy also reported two well‑documented wildlife poisoning events attributed to saxitoxin: northern fur seals on St. Paul Island (August 2024) and a separate event on St. George Island (August 2025). She said those events, along with the prevalence data, create a clear public‑health and subsistence concern and argued for continued surveillance and improved local laboratory capacity and reporting pathways.

Why it matters: the statistical linkage of short‑term accumulated heat and open‑water anomalies with toxin concentrations signals a climate‑mediated risk pathway into Arctic food webs. The presentation emphasized implications for marine mammal health, subsistence food safety, and community monitoring needs.