June 13, 2024

Impacts of U.S. Navy Training Events on Blainville’s Beaked Whale (Mesoplodon densirostris) Foraging Dives in Hawaiian Waters


Roanne Manzano-Roth, E. Elizabeth Henderson, Stephen W. Martin, Cameron Martin, and Brian Matsuyama


Abstract: Blainville’s beaked whales (Mesoplodon densirostris) were detected in recorded acoustic data collected before, during, and after February and August U.S. Navy training events in 2011, 2012, and 2013 at the Pacific Missile Range Facility in Kauai, Hawaii. Beaked whale clicks were automatically detected and manually verified to ensure they fit characteristics of foraging echolocation clicks. Verified foraging click detections were spatially and temporally clustered to represent group vocal periods (GVPs) of beaked whale foraging dives. More GVPs were detected before training events than during or after the training events, and GVPs were detected more on hydrophones at the edges and in the southern portion of the range during sonar activity. However, there were also interannual differences in GVP counts across training event phases, indicating that baseline variability in Blainville’s beaked whale GVPs must be distinguished from reduced foraging dive activity during training events with sonar activity to understand the true impact of sonar.
Key Words: Navy activity, mid-frequency active sonar, Blainville’s beaked whales, Mesoplodon densirostris, beaked whale behavior, Hawaii beaked whales, beaked whale group vocal periods
Document Type: Research Article
DOI: https://doi.org/10.1578/AM.42.4.2016.507
Page Numbers: 507-518


Info SKU: Vol__42__Iss__4__Manzano_Roth Category: