Gulf of Alaska | Lower Trophic Levels
Paralytic shellfish toxins in southern Alaska fish and invertebrates: Trophic transfer risks and implications Presenter: Lynn Wilking , lynn.wilking@noaa.gov, CSS Inc. Lauren Chacho , lauren.chacho@noaa.gov Bruce Wright , bwright@kniktribe.org, Knik Tribe
Julie Matweyou , jamatweyou@alaska.edu Rance Hardison , rance.hardison@noaa.gov Chris Holland , chris.holland@noaa.gov Xuining Du , xuiningdu@gmail.com Rob Campbell , rcampbell@pwssc.org, Prince William Sound Science Center Steve Kibler , steve.kibler@noaa.gov, NOAA
Annual blooms of the dinoflagellate Alexandrium catenella occur in Alaska each spring/summer, producing potent neurotoxins (PSTs) that cause paralytic shellfish poisoning (PSP). These PSTs can accumulate in shellfish, posing a human health risk, but can also transfer to zooplankton grazers, filter feeders, and other biota. PSTs in these other organisms have the potential to cascade through the food web via trophic transfer pathways. Here we report results from a project examining PSTs in marine fishes and invertebrates across southern Alaska where Alexandrium blooms and shellfish toxicity are known to occur. Samples were collected in Lower Cook Inlet, Prince William Sound, the Kodiak Archipelago, the Alaska Peninsula, the Aleutian Islands, and southeast Alaska from 2017-2022 and were analyzed via ELISA and HPLC. Data from 1,014 forage fish, 383 predatory fish, and 20 invertebrate taxa were analyzed, with the highest toxin concentrations observed in bivalve-consuming invertebrates such as crabs (1,560 µg STX Eq. 100 g-1) and sea stars (672 µg STX Eq. 100 g-1). These concentrations are well over the FDA regulatory limit of 80 µg STX Eq. 100 g-1. Forage fish contained up to 758 µg STX Eq. 100 g-1 and at least low PST levels (>5 µg STX Eq. 100 g-1) in 48% of samples. Toxins were present in tissues of predatory fish of all commercially important species with the highest concentrations observed in the kidney (170 µg STX Eq. 100 g-1), liver (103 µg STX Eq. 100 g-1), and digestive organs (54 µg STX Eq. 100 g-1). The prevalence of PSTs in key prey species such as the Pacific sand lance indicates significant trophic transfer risks to marine mammals, seabirds, and other marine predators. Low toxin levels in the muscle tissue of predatory fish suggest a low risk to human health and the Alaska seafood industry, however consumers of urchins and fish or invertebrate organs or byproducts may be at risk of PSP, especially during peak Alexandrium bloom season.
Alaska Marine Science Symposium 2023 127
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