Arctic | Fishes and Fish Habitats DOCTORATE POSTER PRESENTATION
Trophic resource use by Arctic fishes across Beaufort Sea coastal lagoons Presenter: Sydney Wilkinson , swilkinson4@alaska.edu, University of Alaska Fairbanks Vanessa von Biela , vvonbiela@usgs.gov, USGS Alaska Science Center Benjamin Barst , , University of Fairbanks Lara Horstmann , lahorstmann@alaska.edu, University of Alaska Fairbanks Todd Sformo , todd.sformo@north-slope.org, North Slope Borough Dept. of Wildlife Management Trent Sutton , tmsutton@alaska.edu, University of Alaska Fairbanks Carla SimsKayotuk , Carla.SimsKayotuk@north-slope.org, North Slope Borough Nora Jane Burns , Norajane.Burns@north-slope.org, North Slope Borough Kenneth Dunton , ken.dunton@utexas.edu, University of Texas at Austin Katrin Iken , kbiken@alaska.edu, University of Alaska - Fairbanks
The Arctic is heating up nearly four times faster than the rest of the planet as reflected by warming ocean and coastal waters, reduced sea ice extent, thawing permafrost, and eroding coastlines. These changes affect the availability of organic matter from various marine or terrestrial origins that form the base of coastal lagoon food webs. The consequences to nearshore food webs for fish are manifested through shifts in their species composition, abundance, growth, and reproduction. Such adjustments can differ regionally or by species. Here, we aim to determine trophic resource use in multiple marine and diadromous fish species from several Arctic Beaufort Sea coastal lagoons using short and long time-scale markers of diet. First, a short-term diet snapshot was determined from stomach contents of Arctic fishes (Arctic cod, saffron cod, Arctic cisco, least cisco, fourhorn sculpin, Dolly Varden) from three regions (Utqiaġvik, Prudhoe Bay, Kaktovik). Analysis of diet composition revealed differences among species and by region. Secondly, trophic niche width, trophic position, and ultimate carbon sources of these six fish species at longer time scales (months) were determined by fatty acid analysis, bulk carbon and nitrogen stable isotopic analysis, and compound-specific amino acid carbon stable isotope analysis. Long-term markers indicated that marine residents assimilated carbon at higher tropic levels with strong connections to marine primary producers. Conversely, diadromous species feed at lower trophic levels and source carbon from a wider variety of organic matter sources. Our findings provide a better understanding of the current trophic resource for fish species that are important ecologically and for local subsistence. This work demonstrates the diversity of carbon sources that are seasonally available to sustain coastal fish populations in the context of anticipated ecosystem disruptions associated with climate warming.
Alaska Marine Science Symposium 2023 219
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