Search

Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but increased markedly after the development of naval mid-frequency active sonar (MFAS). The temporal and spatial associations between atypical BW MSEs and naval exercises were first observed in the Canary Islands, Spain, in the mid-1980s. Further research on BWs stranded in association with naval exercises demonstrated pathological findings consistent with decompression sickness (DCS). A 2004 ban on MFASs around the Canary Islands successfully prevented additional BW MSEs in the region, but atypical MSEs have continued in other places of the world, especially in the Mediterranean Sea, with examined individuals showing DCS. A workshop held in Fuerteventura, Canary Islands, in September 2017 reviewed current knowledge on BW atypical MSEs associated with MFAS. Our review suggests that the effects of MFAS on BWs vary among individuals or populations, and predisposing factors may contribute to individual outcomes. Spatial management specific to BW habitat, such as the MFAS ban in the Canary Islands, has proven to be an effective mitigation tool and mitigation measures should be established in other areas taking into consideration known population-level information. [ABSTRACT FROM AUTHOR]

The article offers information on topics related to beaked whales. Topics mentioned include the rostrum deformities of whales, its behavior, and the species diversity of whales. Topics mentioned include the health management of marine mammals, the stranded northern bottlenose whale, and the causes of deformities in whales including acquired malformations, predation, and competition.

Data on 27 mesoplodont whales are compiled from the original nineteenth century published records from Britain, Ireland, Europe and the United States. These data comprise the type specimen of Sowerby's beaked whale (Mesoplodon bidens) and 26 other records, all referred to the taxon M. bidens. Records may include the following information: specimen total length, sex, date of discovery and the locality, pigmentation pattern, external morphology, osteology and soft-tissue anatomy. This information is summarized here from the original descriptions. Only a handful of these specimens was externally complete when described at first hand. [ABSTRACT FROM AUTHOR]

James Sowerby's life in London, his zoological works, and his natural history collections are briefly reviewed. The location and date of the stranding and subsequent description of the type specimen of Mesoplodon bidens is discussed. This and other information pertaining to the two original publications by Sowerby is reviewed and the history of the type cranium and mandible is described. [ABSTRACT FROM AUTHOR]

The article explores the presence of the Longman's beaked whale, Indopacetus pacifus, in Maui, Hawaii based on a stranding and necropsy findings. It emphasizes that the presence of such whale is confirmed through genetic testing of the specimen. It mentions the detection of morbillivirus infection in the species. It also notes the role of encephalitis in the stranding if there is a neurological dysfunction in the whale.

The article presents a study which investigates the increased behavior of beaked whales (BW) in Aleutian Islands, Alaska due to several mass strandings that have been linked to military sonar exercises. It mentions that the study deployed a high-frequency acoustic recording package to BW. It notes that due to inaccessible and remote location of sea during much of the year, longterm autonomous acoustic monitoring may guide to further understanding of the ecology and behavior of beaked whales.

Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom- mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2-3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2-3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 μPa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define disturbance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

`There have been several incidents when Navy sonar operations at sea coincided in time and location with the mass stranding of marine mammals, particularly beaked whales. Filadelfo et al. (this issue) compiled historical data on large-scale naval exercises and found significant correlations with whale mass strandings in some locations but not in others. In the present study, we compile information on Navy operations off southern California and single strandings of several cetacean species to see if there is a correlation between strandings and Navy exercises in this area. We use information on the state of decomposition of the stranded animals to treat the actual time of stranding as a random variable, and we simulate the correlation between Navy activity and strandings with a Monte Carlo model. For gray whales (Eschrichtius robustus), the 95% confidence interval (CI) for the ratio of odds of a stranding occurring as a result of Navy exercises to the odds of a stranding occurring naturally was (0.879, 1.582), consistent with the null hypothesis of no difference in stranding rates between times of Navy exercises and other times. For other species, the 95% CI for the odds ratio was (0.716, 1.394), which is, again, consistent with the null hypothesis. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented concerning implication of naval sonar operations in mass strandings particularly of beaked whales in the Canary Islands.

On 29 February 2011 a strap-toothed beaked whale Mesoplodon layardii stranded in the mouth of the Pyin Sa Lu and Thaung Du rivers bordering the northern Indian Ocean in Myanmar at approximately 16°N of the equator. This stranding occurred more than 5000 km from the normal distribution of the species in cold temperate waters below 35°S. Mesoplodonts are the most poorly known of all cetaceans; however, due to the large number of documented strandings and the species' distinctive appearance, the distribution of strap-toothed beaked whales is probably the best known of the genus. For these reasons, the Myanmar stranding is believed to be an anomalous extra-limital occurrence rather than an extension of the species' normal distribution. [ABSTRACT FROM AUTHOR]

On 25 March 2008, a stranded Cuvier's beaked whale was discovered on the southern coast of the Moray Firth in north-east Scotland. Whilst strandings of the species are not uncommon in Scotland, the vast majority occur along the Atlantic coasts to the west of Scotland and Ireland. By comparison, records from the North Sea coast are notably absent, and this event is believed to be the first documented stranding of a Ziphius cavirostris from this mainland coastal region until now. Due to the severe state of decomposition of the specimen, no necropsy was made and therefore the cause of death could not be determined. However, this event may have been linked to a number of other beaked whale strandings in Scotland at this time. Whilst the North Sea region is considered to be an entrapment area for several species of oceanic whale, the Cuvier's beaked whale is rarely thought to travel far enough north to enter this trap. However, the phenology of these and other recent Cuvier's beaked whale strandings would suggest a possible northern range expansion for this species in UK waters, which may explain the increasing number of incidental events now being observed. [ABSTRACT FROM PUBLISHER]