Off-range beaked whale study: Behavior and demography of Cuvier s beaked whale at the Azores
Abstract
One of the prime Life Sciences research topics at ONR involves behavioral responses of marine mammals to man-made sounds. There is a pattern of atypical mass strandings of several beaked whale species that coincide with naval sonar exercises; the cause(s) of stran"ding remain unknown, but might include strong avoidance responses, resulting in prolonged deep dives. Strandings, but also sub-letha"l changes in behavior and habitat-use resulting from sonar exposure pose a significant risk of negative effects at the population-le"vel. The type and severity of behavioral responses can strongly vary with the context of the exposure, and may be subject to previou""s experience. Therefore, there is a critical need for the study of off-range and natural behavior of beaked whales to enable assessm""ent of the universality and biological significance of on-rangte responses, to provide a full scientific basis for Navy mitigation m"easures. The proposed research will help fill these data gaps and provide a better scientific basis for monitoring and mitigation policies. Advances in our knowledge of th"e effects of naval sonar on beaked whale behavior, originating from BRSs have confirmed that beaked whales, and Cuvier s beaked whal""e in particular, are sensitive to naval sonar. They generally exhibit strong responses to experimental exposure which have the poten"tial to translate to effects at population level. The relatively small number of individuals tested typically show an avoidance resp"osne, coupled with prolonged and deeper dives, cessation of vocalizing and feeding (Tyack et al 2011, DeRuite et al 2013). Results,"" however, also indicate strong potential for context dependent behavioral response and sensitivity (DeRuite et al 2013, Miller et al" 2015). A concern therefore with the status of our scientific knowledge is that most of this information has been collected on our c"lose to US Naval ranges (Harris & Thomas 2015). Due to habituation, sensitization, or migration form the area, the behavior of indiv"iduals in those areas may not be representative for beaked whales from inhabiting off-range habitats. Specific concern extends to on"-range population size and demography (Claridge 2013). Furthermore, given the limited knowledge on the natural behavior of beaked wh""ales, responses of a small subset of individuals are not easily interpreted at larger scales; i.e. it remains challenging to interpr""et how context influences responsiveness, what is the severity of an observed response within the spectrum of natural behavior and t""o what degree responsiveness varies across populations (Harris & Thomas 2015). In turn, this limits accurate environmental assessmen""t of sonar effects. Here, we" aim to advance the knowledge on the natural behavior and population demography of Cuvier s beaked whale in an off-range habitat (th"e Azores, North Atlantic) to further our understanding of Cuvier s beaked whale behavioral response to sonar and enhance the ability"" for effective, science-based mitigation measures. Building on an existing data-set, this study will aim to enhance understanding of"" Cuvier s beaked whale behavior, demography and behavioral resposne by 1) providing new data, and 2) enabling comparison of behavior"al patterns and population demography between different study sites and on- and off-range areas through expert collaborations.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 07, 2017
- Source ID
- N000141712715
Entities
People
- Fleur Visser
Organizations
- Office of Naval Research
- United States Navy