Blainville's Beaked Whale Mesoplodon Research Articles

The post-mortem history of a bone revealed by its trace element signature: The case of a fossil whale rostrum

Studies dedicated to palaeoenvironments and taphonomy have made wide use of rare earth elements (REE) contents of fossil bones as proxies. However, the complex diagenetic history of individual specimens combined with intra-bone REE fractionation and the uncertain timing of REE uptake generally prevents the robust interpretation of REE patterns. In this case study we show that combining REE analysis with, on the one hand, histology and microstructural observations and, on the other hand, additional analyses of other trace elements, allows deciphering at least three distinct trace element uptake stages, as well as one leaching event.More than 35 trace elements (including the REE) are analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) within compact rostrum bones of the Miocene-Pliocene beaked whale Globicetus hiberus from deep-sea deposits and a comparable extant specimen (Blainville's beaked whale Mesoplodon densirostris). Comparison of the extinct and the extant bones allows a better quantification of the diagenetic trace element content.This study highlights the crucial role played by diagenetic minerals such as the Fe-Mn oxyhydroxides in the uptake and release of trace elements (Co, Ni, Ti, V, Zr, Hf and Nb) and REE by bones, in response to changes of the diagenetic fluid redox conditions over time. Such changes of the geochemical environment help constraining the post-mortem history of the bone and its interaction with diagenetic fluids. We conclude that the unique interpretation of geochemical proxies within individual fossil bones requires a thorough investigation of each individual specimen.

Physiological, morphological, and ecological tradeoffs influence vertical habitat use of deep-diving toothed-whales in the Bahamas.

Dive capacity among toothed whales (suborder: Odontoceti) has been shown to generally increase with body mass in a relationship closely linked to the allometric scaling of metabolic rates. However, two odontocete species tagged in this study, the Blainville’s beaked whale Mesoplodon densirostris and the Cuvier’s beaked whale Ziphius cavirostris, confounded expectations of a simple allometric relationship, with exceptionally long (mean: 46.1 min & 65.4 min) and deep dives (mean: 1129 m & 1179 m), and comparatively small body masses (med.: 842.9 kg & 1556.7 kg). These two species also exhibited exceptionally long recovery periods between successive deep dives, or inter-deep-dive intervals (M. densirostris: med. 62 min; Z. cavirostris: med. 68 min). We examined competing hypotheses to explain observed patterns of vertical habitat use based on body mass, oxygen binding protein concentrations, and inter-deep-dive intervals in an assemblage of five sympatric toothed whales species in the Bahamas. Hypotheses were evaluated using dive data from satellite tags attached to the two beaked whales (M. densirostris, n = 12; Z. cavirostris, n = 7), as well as melon-headed whales Peponocephala electra (n = 13), short-finned pilot whales Globicephala macrorhynchus (n = 15), and sperm whales Physeter macrocephalus (n = 27). Body mass and myoglobin concentration together explained only 36% of the variance in maximum dive durations. The inclusion of inter-deep-dive intervals, substantially improved model fits (R2 = 0.92). This finding supported a hypothesis that beaked whales extend foraging dives by exceeding aerobic dive limits, with the extension of inter-deep-dive intervals corresponding to metabolism of accumulated lactic acid. This inference points to intriguing tradeoffs between body size, access to prey in different depth strata, and time allocation within dive cycles. These tradeoffs and resulting differences in habitat use have important implications for spatial distribution patterns, and relative vulnerabilities to anthropogenic impacts.

Tracking marine mammals in 3D using electronic tag data

Summary Information about at‐depth behaviour of marine mammals is fundamental yet very hard to obtain from direct visual observation. Animal‐borne multisensor electronic tags provide a unique window of observation into such behaviours. Electronic tag sensors allow the estimation of the animal's 3‐dimensional (3D) orientation, depth and speed. Using tag flow noise level to provide an estimate of animal speed, we extend existing approaches of 3D track reconstruction by allowing the direction of movement to differ from that of the animal's longitudinal axis. Data are processed by a hierarchical Bayesian model that allows processing of multisource data, accounting for measurement errors and testing hypotheses about animal movement by comparing models. We illustrate the approach by reconstructing the 3D track of a 52‐min deep dive of a Blainville's beaked whale Mesoplodon densirostris adult male fit with a digital tag (DTAG) in the Bahamas. At depth, the whale alternated regular movements at large speed (>1·5 m s ‐1) and more complex movements at lower speed (<1·5m s‐1) with differences between movement and longitudinal axis directions of up to 28. The reconstructed 3D track agrees closely with independent acoustic‐based localizations. The approach is potentially applicable to study the underwater behaviour (e.g. response to anthropogenic disturbances) of a wide variety of species of marine mammals fitted with triaxial magnetometer and accelerometer tags.

Records of beaked whales (family Ziphiidae) in Western Australian waters

Western Australia has an extensive coastline extending 12889 km (excluding islands) from latitude 35 degrees in the south to 14 degrees in the north. The extensive coastline intersects the distribution of many species of beaked whale. A total of 74 Ziphiidae were recorded as stranded along the Western Australian coast between 1940 and 2010 (70 years). Ten of the 21 species of beaked whales currently recognized taxonomically worldwide have been observed in Western Australia with True's beaked whale Mesoplodon mirus and Shepherd's beaked whale Tasmacetus shepherdi recorded more than elsewhere in Australia. Western Australia has the highest species diversity (10) of beaked whale strandings compared to other Australian states and regions. Gray's beaked whale, Mesoplodon grayi, was the most commonly reported species (33 records) and had the largest mass stranding group size (seven) of the beaked whales stranded in Western Australia. The records presented in this paper confirm the distribution of Arnoux's beaked whale Berardius arnuxii, strap-toothed beaked whale Mesoplodon layardii, Shepherd's beaked whale, Blainville's beaked whale Mesoplodon densirostris in Western Australian waters. The records presented of True's beaked whale confirm its presence in Australian waters, with Western Australia a possible key location for this species. Factors causing strandings and death should be investigated in future wherever possible, particularly the rostral injuries reported for six beaked whales. Beaked whale species identification should be confirmed through genetic analysis in future to maximize certainty of species identification.

Trackline and point detection probabilities for acoustic surveys of Cuvier's and Blainville's beaked whales

Acoustic survey methods can be used to estimate density and abundance using sounds produced by cetaceans and detected using hydrophones if the probability of detection can be estimated. For passive acoustic surveys, probability of detection at zero horizontal distance from a sensor, commonly called g(0), depends on the temporal patterns of vocalizations. Methods to estimate g(0) are developed based on the assumption that a beaked whale will be detected if it is producing regular echolocation clicks directly under or above a hydrophone. Data from acoustic recording tags placed on two species of beaked whales (Cuvier's beaked whale-Ziphius cavirostris and Blainville's beaked whale-Mesoplodon densirostris) are used to directly estimate the percentage of time they produce echolocation clicks. A model of vocal behavior for these species as a function of their diving behavior is applied to other types of dive data (from time-depth recorders and time-depth-transmitting satellite tags) to indirectly determine g(0) in other locations for low ambient noise conditions. Estimates of g(0) for a single instant in time are 0.28 [standard deviation (s.d.) = 0.05] for Cuvier's beaked whale and 0.19 (s.d. = 0.01) for Blainville's beaked whale.

First record of Mesoplodon densirostris (Blainville 1817) from continental East Africa

Blainville's beaked whale Mesoplodon densirostris is one of the most widely distributed members of the family Ziphiidae (the beaked whales). However, its exact distribution in many parts of the world remains unknown. On 24 November 2004, the partly skeletonised carcass of an adult male Blainville's beaked whale was found on a beach north of the Sabaki River in Kenya (03°09′ S, 40°08′ E). This is the first confirmed record for this species for continental East Africa, and contributes to our knowledge of the distribution of Blainville's beaked whale in the western Indian Ocean.

First record of Blainville's Beaked Whale Mesoplodon densirostris in Fiji

LIttle Is known about the conservation status and geographic range of beaked whales. This note provides the first record of a Blainville's Beaked Whale Mesoplodon densirostris in Fijian waters, and contributes to the available knowledge of a species poorly known in the South Pacific region. On 11 November 2003, a female beaked whale stranded near Viti Levu, Fiji. A lack of suitable references and unfamiliarity with diagnostic morphological characters inhibited species identification at the time of stranding. However, we were able to identify this specimen by using molecular genetic information and applying a diagnostic character approach. DNA sequences from the unknown specimen exhibited nucleotide character states that unambiguously identified it as a Blainville's Beaked Whale. Unfortunately, a lack of associated data collected in this particular event emphasizes a common situation around the world: untrained or poorly equipped personnel (municipalities, governmental agencies or local residents) must manage stranded marine mammals out of necessity. However, information from these events or opportunistic beach surveys assists In furthering research of conservation status and management needs.

Review of the distribution of Mesoplodon species (order Cetacea, family Ziphiidae) in the North Atlantic

Four species of beaked whales of the genus Mesoplodon regularly occur in the North Atlantic. These are Sowerby's Beaked Whale Mesoplodon bidens, Blainville's Beaked Whale Mesoplodon densirostris, Gervais Beaked Whale Mesoplodon europaeus and True's Beaked Whale Mesoplodon mirus. These four species differ in their distribution within this area. M. bidens is the most northerly recorded species followed by M. mirus. M. densirostris and M. europaeus both generally occur further south and their distributions cross the equator. The distribution of Mesoplodon species may relate to variations in water temperature.