Beaked Whale Strandings and Naval Exercises

Abstract

Mass strandings of beaked whales (family Ziphiidae) have been reported in the scientific literature since 1874. Several recent mass strandings of beaked whales have been reported to coincide with naval active sonar exercises. To obtain the broadest assessment of surface ship naval active sonar operations coinciding with beaked whale mass strandings, a list of global naval training and antisubmarine warfare exercises was compiled from openly available sources and compared by location and time with historic stranding records. This list includes activities of navies of other nations but emphasizes recent U.S. activities because of what is available in publicly accessible sources. Of 136 beaked whale mass stranding events reported from 1874 to 2004, 126 occurred between 1950 and 2004, after the introduction and implementation of modern, high-power mid-frequency active sonar (MFAS). Of these 126 reports, only two reported details on the use, timing, and location of sonar in relation to mass strandings. Ten other mass strandings coincided in space and time with naval exercises that may have included MFAS. An additional 27 mass stranding events occurred near a naval base or ship but with no direct evidence of sonar use. The remaining 87 mass strandings have no evidence for a link with any naval activity. Six of these 87 cases have evidence for a cause unrelated to active sonar. The large number of global naval activities annually with potential MFAS usage in comparison to the relative rarity of mass stranding events suggests that most MFAS operations take place with no reported stranding events and that for an MFAS operation to cause a mass stranding of beaked whales, a confluence of several risk factors is probably required. Identification of these risk factors will help in the development of measures to reduce the risk of sonar-related strandings.

Effective beam pattern of the Blainville's beaked whale (Mesoplodon densirostris) and implications for passive acoustic monitoring

“…Similar data have also been obtained from Cuvier's beaked whale (Ziphius cavirostris), another species considered to be sensitive to sonar (D'Amico et al, 2009). These data have been used to design PAM systems (Mellinger et al, 2007) and to predict the detection rate of beaked whales as a function of sound propagation conditions and ambient noise level (Zimmer et al, 2008).…”

“…Within the last decade, the sensitivity of some species of beaked whales (Cetacea: Odontoceti: Ziphiidae) to naval sonar has been well documented D'Amico et al, 2009), creating a need for effective monitoring in regions where their presence overlaps with navy sonar use. One of the sensitive species, Blainville's beaked whale (Mesoplodon densirostris), dives to great depths to forage, spending only a short period of time at the surface, resulting in a low probability of visual detection Barlow, 1999).…”

The Challenges of Analyzing Behavioral Response Study Data: An Overview of the MOCHA (Multi-study OCean Acoustics Human Effects Analysis) Project

“…The first such BRS was conducted in 2007 and 2008 in the Bahamas (Tyack et al, 2011) with the aim of collecting baseline data on animal behavior, and conducting CEEs to measure responses to different sound stimuli. A major focus of the Bahamas work was beaked whales, which are thought to be some of the species most vulnerable to sounds from sonar exercises as they make up the majority of animals stranded in association with naval sonar exercises (D'Amico et al, 2009). A second project, 3S (for "Sea mammals, Sonar, Safety"), which aimed to determine behavioral responses of killer, sperm and pilot whales to different sonar frequencies, commenced in 2006 with funding from The Royal Norwegian and Dutch Navies, and in 2008 additional US-Naval support allowed a significant expansion of the effort .…”

Risk mapping for sensitive species to underwater anthropogenic sound emissions: Model development and validation in two Mediterranean areas

“…sea turtles) (Klima et al, 1988;McCauley et al, 1999McCauley et al, , 2000. Some high energy sound sources have been, in fact, correlated to mortality events of marine mammals, the majority of these involving atypical mass strandings of beaked whales (D'Amico et al, 2009;Evans and Miller, 2004;Freitas, 2004;Frantzis, 1998;Martín Martel, 2002;Martín et al, 2004;Parsons et al, 2008;Simmonds and Lopez-Jurado, 1991). Beaked whales represent one of the groups of large marine mammals whose behavior and ecology is largely unknown (MacLeod and Mitchell, 2006;MacLeod and D'Amico, 2006).…”

“…Even though the overall knowledge about beaked whale biology is increasing with recent studies, the exact mechanisms by which anthropogenic sound production may affect beaked whales are still unclear (Cox et al, 2006;MacLeod and D'Amico, 2006;Parsons et al, 2008). According to D'Amico et al (2009) the majority of beaked whale strandings do not apparently correlate in space and time with naval activities.…”