The Effect of Deep-Water Multibeam Mapping Activity on the Foraging Behavior of Cuvier’s Beaked Whales and the Marine Acoustic Environment

• Main Author: Kates Varghese, Hilary Suzanne Curran
• Format: Text
• Language: unknown
• Published: University of New Hampshire Scholars' Repository 2021
• Subjects: Before-After Control-Impact; Cuvier's beaked whale; foraging behavior; multibeam echosounder; ocean mapping; soundscape; toothed whales
• Online Access: https://scholars.unh.edu/dissertation/2648; https://scholars.unh.edu/cgi/viewcontent.cgi?article=3652&context=dissertation

Sound can propagate great distances underwater and is an important mode for marine life to obtain information. Human activities in the ocean such as global shipping, coastal construction, gas and oil exploration, and mapping navigation routes intentionally and unintentionally emit sound into the ocean, potentially interacting with marine life. Therefore, it is essential that the effects of anthropogenic noise on marine life and the ambient marine acoustic environment be understood. Most of the work, to date, has focused on the impact of low-frequency (<1 kHz) sources such as shipping noise, which is ubiquitous in the ocean, and mid-frequency (1-10 kHz) sources such as naval sonar, to which many marine mammals have shown to be sensitive. The effect of these sources can be as salient as a mass stranding event or as benign as an animal swimming away from a source of noise with no other effect. Less work has focused on higher frequency sources (>10 kHz), including ocean-mapping sonar systems. However, most marine mammals, namely toothed whales (odontocetes), are capable of hearing mapping-sonar signals. The exposure of marine mammals to anthropogenic sound sources in the open ocean is regulated by the National Marine Fisheries Services through the Marine Mammal Protection Act (MMC 2015), the Endangered Species Act (DoI 2003), and the National Environmental Policy Act. Without a better understanding of the interaction of mapping sonar with marine mammals, the current guidelines imposed for marine mammal protection may not be protective enough, or alternatively, may be too conservative. To gain a better understanding of the potential effect of mapping sonar and marine mammals, a scenario was examined that is possible to occur and has a high potential for a biologically meaningful interaction between mapping sonar and a sensitive marine mammal species: a 12-kHz multibeam echosounder (MBES) mapping survey and beaked whale foraging. This represents a possible interaction since 1) the relatively low frequency of the ...