Arctic | Mammals
From phytoplankton to walruses: Developing trophic-transfer models of saxitoxins in a crucial Alaskan food chain Presenter: Patrick Charapata , patrick.charapata@noaa.gov, NOAA Northwest Fisheries Science Center
Evie Fachon , efachon@whoi.edu, Arctic Research Consortium of the United States Donald Anderson , danderson@whoi.edu, Woods Hole Oceanographic Institution Gay Sheffield , ggsheffield@alaska.edu, University of Alaska Fairbanks Emily Bowers , emily.bowers@noaa.gov, NOAA Northwest Fisheries Science Center Robert Pickart , rpickart@whoi.edu, Woods Hole Oceanographic Institute Kathi Lefebvre , kathi.lefebvre@noaa.gov, Northwest Fisheries Science Center (NOAA)
The high levels of paralytic shellfish toxins (PSTs), including saxitoxins (STXs), produced during harmful algal bloom (HAB) events by the dinoflagellate Alexadrium catenella threaten wildlife and human health. Previous reports of A. catenella blooms in northern and western Alaska were rare because the cold waters of the northern Bering, Chukchi, and Beaufort Seas suppressed cyst germination, which initiates blooms. However, increasing ocean temperatures has resulted in a reduction in the extent, duration, and quality of sea ice and the subsequent documentation of multiple dangerous HABs in western and northern Alaskan waters. Further, STXs have been measured in various marine mammal species indicating STXs are present throughout Alaskan food webs. Currently, it is unknown how these toxins are transferred throughout the food web, nor do we know the exposure levels of STXs that result in deleterious effects to Alaskan marine wildlife. The objective of this study is to construct trophic transfer models of STXs throughout a prominent Alaskan food chain (phytoplankton [A. catenella] --> clams --> walruses) using opportunistic samples collected during 2019-2022 from the Bering, Chukchi, and Beaufort Seas. Specifically, STXs were measured in phytoplankton pellets consisting of A. catenella, homogenized clam samples, and walrus tissues (feces and stomach contents) to acquire empirical data for model development. Sample processing is ongoing and final sample sizes are unknown. We plan to present potential approaches for building trophic transfer and/or biokinetic models of STXs using empirical data and model parameters (e.g., filtration, elimination, and ingestion rates) from the literature. The results of this study will provide a blueprint for developing additional predictive trophic transfer models of STXs for other important Alaskan food chains. The optimization and validation of these models will provide a tool for management and researchers to identify bloom conditions that may threaten a variety of essential marine resources for coastal communities throughout northern and western Alaska.
Alaska Marine Science Symposium 2023 282
Made with FlippingBook flipbook maker