Gulf of Alaska | Fishes and Fish Habitats DOCTORATE POSTER PRESENTATION Shifts in nearshore fish assemblages with the reintroduction of sea otters Presenter: Lia Domke , lkdomke@alaska.edu, University of Alaska Fairbanks Rebecca Cates , rebecca.cates@noaa.gov, NOAA Alaska Fisheries Science Center Jessica Whitney , jmwhitney2@alaska.edu, University of Alaska Southeast Alexandra Waldschmidt , ajwaldschmidt@gmail.com
Emma Beaver , beaverec@whitman.edu Bryce Noel , Bryce.noel2017@gmail.com Ginny Eckert , gleckert@alaska.edu, University of Alaska Fairbanks
The reintroduction of sea otters in Southeast Alaska provides the opportunity to explore the role of apex predators in affecting nearshore marine community structure. Nearshore marine regions are important because they are productive, diverse ecosystems that provide critical refuge, migratory, and residential habitat for a variety of species. We examined fish species composition and abundance using beach seines in areas with and without sea otters. We employed a before- after-control-impact framework to quantify shifts in nearshore fish communities and to distinguish which changes may be associated with recolonization of sea otters, while accounting for changes over time. Fish community composition from sites sampled before, after, and in control, and impacted locations did not differ, meaning that fish assemblages were similar across time and with sea recolonization. On the other hand, we found that species richness increased over time after sea otters colonized and did not differ over time in areas where they had not colonized. Further work is needed to identify potential mechanisms to explain these results. Potentially sea otters, through indirect impacts, allow for more niches or reduce interspecific competition, thereby increasing species richness. This work reinforces the role of apex predators, along with various environmental, interannual, and species-specific forces, as important to structuring nearshore marine fish assemblages.
Alaska Marine Science Symposium 2023 185
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