Integrated Soundscape Analysis and Improved Tracking of Marine Mammals in Kotzebue Sound, Alaska
The primary objectives of this research are: to understand how natural abiotic, biological and anthropogenic sound sources contribute to the soundscape of Kotzebue Sound; and to analyze call behavior of marine mammals that are prioritized by the Native Village of Kotzebue, such as Bearded seals or Ugruk, to improve our knowledge of seasonal distribution, habitat use, and acoustic ecology.
A soundscape is a measure of all contributing factors to the ambient noise floor. Typically ocean soundscapes are a combination of biological noise, natural abiotic noise (ice, wind, weather, waves, and earthquakes) and anthropogenic noise (ships, echo sounders, seismic activity, construction, etc). Sound is particularly important in shallow basins like Kotzebue where sound waves reflect off the ocean bottom many times, augmenting their impact.
Marine mammals utilize sound for crucial life tasks such as communication, navigation, foraging and finding mates. Over evolutionary time, marine mammals have adapted acute hearing and calling abilities to facilitate acoustic communication in the rugged and vast ocean environment. As climate change continues to alter the physical environment by altering weather patterns, decreasing sea ice, and increasing access to the ocean for anthropogenic activities, marine soundscapes are changing drastically. As a result marine mammals may suffer not only from the direct environmental consequences of climate change but also from impaired communication ability.
Research tracking changes in ocean noise will allow for enhanced monitoring and management of ecologically important regions such as the Arctic. This project is a collaboration between researchers at UC Santa Cruz: Friedlaender Laboratory, California Ocean Alliance, Wildlife Conservation Society and the Native Village of Kotzebue and aims to describe soundscapes and marine mammal behavior through passive acoustic monitoring in Kotzebue Sound, Alaska. As marine mammals are valuable subsistence resources for Native Alaskan people, conservation of these stocks preserves cultural practices and food sovereignty for coastal indigenous communities. Results of this study will bolster the community’s own advocacy efforts to preserve the vitality of the region for marine mammal species during a period of rapid environmental change.
Acoustic data is being collected year round by moorings anchored to the seafloor throughout Kotzebue Sound. These moorings contain three instruments to detect various types of noise and to locate the mooring when it’s ready to be retrieved. Autonomous recorders will record calls produced by marine mammals such as bearded seals, walrus, beluga whale and killer whale. Based on the timing and structure of the calls we can learn when animals visit the region, where they go and what they’re doing there.