2023_programme: Exploring the relationship between odontocete foraging vocalizations and the Bering Sea Cold Pool

• Session: 05. Marine Bioacoustics
  Organiser(s): Jennifer Miksis-Olds
• Lecture: Exploring the relationship between odontocete foraging vocalizations and the Bering Sea Cold Pool [invited]
  Paper ID: 1871
  Author(s): Miksis-Olds Jennifer, Seger Kerri, Johnson Jennifer
  Presenter: Miksis-Olds Jennifer
  Abstract: The Cold Pool is a subsurface layer that is formed in the summer due to stratification and is characterized by previous winter conditions and water temperatures below 2oC. This area of relatively cooler temperatures impacts zooplankton dynamics, driving two different energetic pathways. The cold regime pathway favors larger zooplankton species which increases forage fish biomass, whereas the warm regime pathway favors smaller zooplankton species which decreases forage fish biomass. Since odontocetes rely on forage fish for survival and use echolocation to find them, tracking foraging vocalizations could lead to a better understanding of the implications of a variable Cold Pool on the Bering Sea’s food web. Passive acoustic data that captured odontocete vocal activity was examined in the context of co-located environmental data to determine whether odontocete vocal presence is related to Cold Pool dynamics and if odontocete foraging behavior changes as a function of Bering Sea climate regime. Cold Pool strength and presence is linked to Bering Sea climate regimes and was observed to have an impact on odontocete presence and foraging behavior. Vocal foraging dynamics suggest that sperm whales spend more time searching for prey in warm years when the Cold Pool is reduced but are more successful at capturing prey during cold years when the Cold Pool is stronger. Beluga whale vocal activity was relatively consistent across regimes but peaked during the warm regime. Killer whale vocal activity peaked in both warm and cold regimes with indicators of increased prey capture during cold years when the Cold Pool was well established. A reduced Cold Pool presence is increasingly likely as Arctic and sub-Arctic water temperatures rise. Foraging activity of apex predators may serve as a sentinel indicator or early warning signal of future ecosystem change related to prey availability linked to Cold Pool dynamics.
• Corresponding author: Dr Jennifer Miksis-Olds
  Affiliation: University of New Hampshire, Center for Acoustics Research & Education
  Country: United States
  e-mail: