Acoustic-Based Density Estimates for Cuvier’s Beaked Whales in the Gulf of Alaska

Goal: To use acoustic data collected during the Gulf of Alaska Line Transect Survey (GOALS II) marine mammal survey to estimate densities of Cuvier’s beaked whales in the Gulf of Alaska.

Time Period: 2015

Our Role: To use PAMGuard’s Viewer Mode software to estimate perpendicular distances to beaked whales detected acoustically during the GOALS II survey. To create robust models to estimate the abundance of Cuvier’s beaked whales (and, if there are sufficient numbers of encounters, Baird’s beaked whales) using acoustic data collected during the GOALS II survey.

Bio-Waves, Inc. is using acoustic data collected during the 2013 GOALS II marine mammal shipboard survey to create robust models for density estimation of Cuvier’s beaked whales and, if possible, Baird’s beaked whales in the Gulf of Alaska. Density estimation is important for setting regulatory requirements under the Marine Mammal Protection Act (MMPA) and the Endangered Species Act (ESA), however beaked whale distribution and abundance in the Gulf of Alaska is currently poorly known. Beaked whales spend the vast majority of their time submerged, regularly dive to depths of hundreds to thousands of meters, typically occur in small groups, and behave inconspicuously at the surface. These factors make beaked whales extremely difficult to detect and observe using visual methods. They can be differentiated acoustically from other odontocetes by the unique characteristics of their echolocation clicks, and new capabilities in PAM software now make it possible to use the distinctive features of these echolocation clicks to acoustically detect, localize, and classify different species of beaked whales. These acoustic data can be post-processed and analyzed further for the purpose of density estimation and habitat modeling. The data collected in the Gulf of Alaska provide an important opportunity to assess the distribution, habitat use, and abundance of beaked whales in this region the first time. Results of these efforts can, in turn, be used to better inform conservation and management efforts for this ecologically diverse and important region.

Collaborators/Partners: Brenda Rone (National Marine Mammal Laboratory, Alaska Fisheries Science Center), Cascadia Research Collective

Sponsors: NAVFAC Pacific and HDR

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