# Changing Oceans Affect Shellfish Toxins

> **NIH NIH P01** · SITKA TRIBE OF ALASKA · 2024 · $187,579

## Abstract

Harmful algal blooms (HABs) of the dinoflagellate Alexandrium spp. threaten coastal populations of humans
and wildlife in Alaska. Toxins produced by Alexandrium can accumulate in shellfish and other filter feeders and
at high concentrations cause paralytic shellfish poisoning (PSP). In response to community concerns regarding
the safety of shellfish harvest Southeast Alaska Tribal Ocean Research (SEATOR), a network of coastal tribal
communities, created a robust and expansive monitoring program for HABs, shellfish toxins, and ocean
acidification (OA). A major concern for coastal Alaskan communities is how changing climate conditions will
affect the safety of subsistence shellfish harvest. Warming sea surface temperatures, air temperatures, and
increasing acidity have the potential to alter production of toxins by Alexandrium and increase the potential
bloom window into seasons not typically associated with HABs. This uncertainty will be addressed in this
project using a multi-faceted and rigorous approach. Aim 1 will leverage long term monitoring data from
SEATOR (n=3,433 shellfish samples), in situ environmental measurements, remote sensing products, and
traditional ecological knowledge to generate machine learning and mixed effects harmonic models predicting
shellfish toxins from environmental variables. These models will be used to predict future seasonal shellfish
toxin dynamics by incorporating regional downscaled climate projections. Congener specific data generated in
Project 2 will also be analyzed for species specific and spatial trends in association with environmental
variables. Aim 2 will analyze 919 discrete OA samples collected by coastal communities paired with 1,814
previously analyzed discrete samples to investigate spatiotemporal relationships between OA parameters (i.e.
pCO2) on shellfish toxin dynamics. Using OA parameters constrained from Aim 2 and future climate scenarios,
Aim 3 will use in vivo experimentation to examine the effects of changing ocean conditions (temperature,
pCO2) on toxin accumulation and maximum toxicity in subsistence shellfish species. This project creates an
important linkage between empirical models of HABs and shellfish toxicity and climate adaptation planning,
creating outputs of future HAB dynamics which are actionable and will be shared with tribal partners and
communities.

## Key facts

- **NIH application ID:** 10733891
- **Project number:** 1P01ES035551-01
- **Recipient organization:** SITKA TRIBE OF ALASKA
- **Principal Investigator:** John Harley
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $187,579
- **Award type:** 1
- **Project period:** 2024-03-20 → 2029-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10733891

## Citation

> US National Institutes of Health, RePORTER application 10733891, Changing Oceans Affect Shellfish Toxins (1P01ES035551-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10733891. Licensed CC0.

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