Arctic | Mammals
Characterization of contributors to the US Arctic soundscape Presenter: Catherine Berchok , catherine.berchok@noaa.gov, Alaska Fisheries Science Center/Marine Mammal Lab Manuel Castellote , manuel.castellote@noaa.gov, Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA Dimitri Ponirakis , dwp22@cornell.edu, K. Lisa Yang Center for Conservation Bioacoustics, Cornell University Eric Braen , eric.braen@noaa.gov, Cooperative Institute for Climate, Ocean & Ecosystem Studies, University of Washington Arial Brewer , arial.brewer@noaa.gov, Cooperative Institute for Climate, Ocean & Ecosystem Studies, University of Washington Stephanie Grassia , Stephanie.Grassia@noaa.gov, Cooperative Institute for Climate, Ocean & Ecosystem Studies, University of Washington Jenna Harlacher , Jenna.Harlacher@noaa.gov, Cooperative Institute for Climate, Ocean & Ecosystem Studies, University of Washington Brynn Kimber , Brynn.Kimber@noaa.gov, Cooperative Institute for Climate, Ocean & Ecosystem Studies, University of Washington Jessica Knoth , Jessica.Knoth@noaa.gov, Cooperative Institute for Climate, Ocean & Ecosystem Studies, University of Washington Daniel Woodrich , Daniel.Woodrich@noaa.gov, Cooperative Institute for Climate, Ocean & Ecosystem Studies, University of Washington Robyn Angliss , Robyn.Angliss@noaa.gov, Alaska Fisheries Science Center/Marine Mammal Lab As environmental conditions continue to change, contemporary information on the timing and location of marine mammals and the extent of their overlap with anthropogenic activities is important for effective mitigation of impacts from these activities. Long-term passive acoustic recorder moorings remain one of the most cost-effective methods available to observe the impact of this change on marine mammals year-round, and to monitor increases in anthropogenic activities. With funding from the U.S. Navy, we compared three years of results (2016-2019) from eleven mooring sites (some BOEM-funded) located from the Chirikov basin south of Bering Strait to Utqiaġvik on the North Slope. Here, we present and compare the 50th percentile spectrum for the background noise between years, seasons, and mooring sites. We then examine the contribution of each source to the soundscape (at all mooring sites and through all seasons) in three ways: using background noise level exceedence metrics (including contour, area, and compactness); comparing the proportion of temporal overlap of each species/source’s signals with those of other species/sources; and comparing the proportion of time each species/source contributes to its parent category. Results from our work show that biological sources are still the biggest contributors to the soundscape both in terms of prevalence and amplitude levels. There also were not many differences in sound contributions across the three years of this study. Although there have been studies directed toward measurements of background noise levels in the U.S. Arctic, this is the first of its kind to characterize the contributions down to a species level and over a large geographical and temporal scale. Looking forward, the continued decrease in the duration and extent of the ice season is expected to bring with it an increase in vessel shipping, as well as possible commerical fishing and energy exploration and development actitivites. Having an established method for comparison of changes in the composition and output of soundscape contributors, and the resulting increases in background noise, will allow for rapid trend monitoring and mitigation in the future.
Alaska Marine Science Symposium 2023 76
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