A mass stranding of seven Longman’s beaked whales (Indopacetus pacificus) in New Caledonia, South Pacific

International audienceSeven Longman’s beaked whales (Indopacetus pacificus) stranded together in southern New Caledonia on 16 November 2013 (one adult male, two adult females, two subadult females, one calf, and one unknown). At this time, we have no evidence to suggest that this event was an “atypical” mass stranding associated with active naval sonar or other anthropogenic activities. The adult females were slightly larger (618–640 cm) than the adult male (590 cm). The length of the calf (ca. 300 cm) suggests it was less than a year old. Five of the whales were sampled for mitochondrial (mt) DNA analysis to confirm species identification. All shared the same haplotype over 680 bp of the mtDNA control region. High concentrations of Hg, Fe, Se, Zn (all in the liver), and Cd (in the kidneys) were detected. Necropsies revealed plastic debris in the stomach of two of the whales. One of these same whales had chronic gastritis while the other had acute pleurisy and also tested positive for morbillivirus. This infection may have been a major factor behind this mass stranding event

Resurrection of Mesoplodon hotaula Deraniyagala 1963: A new species of beaked whale in the tropical Indo-Pacific

We present genetic and morphological evidence supporting the recognition of a previously synonymized species of Mesoplodon beaked whale in the tropical Indo-Pacific, Mesoplodon hotaula. Although the new species is closely-related to the rare ginkgo-toothed beaked whale M. ginkgodens, we show that these two lineages can be differentiated by maternally (mitochondrial DNA), biparentally (autosomal), and paternally (Y chromosome) inherited DNA sequences, as well as by morphological features. The reciprocal monophyly of the mtDNA genealogies and the largely parapatric distribution of these lineages is consistent with reproductive isolation. The new lineage is currently known from at least seven specimens: Sri Lanka (1), Gilbert Islands, Republic of Kiribati (1+), Palmyra Atoll, Northern Line Islands, U.S.A. (3), Maldives (1), and Seychelles (1). The type specimen (Sri Lanka) was described as a new species, M. hotaula, in 1963, but later synonymized with M. ginkgodens. This discovery brings the total number of Mesoplodon species to 15, making it, by far, the most speciose yet least known genus of cetaceans.Keywords: Species delimitation, Mesoplodon, Nuclear introns, Taxonomy, Y-chromosome, mtDNA, Morphology, Speciation, Beaked whal

Biogeography in the deep : hierarchical population genomic structure of two beaked whale species

Funding for this research was provided by the Office of Naval Research, Award numbers N000141613017 and N000142112712. ABO was supported by a partial studentship from the University of St Andrews, School of Biology; OEG by the Marine Alliance for Science and Technology for Scotland (Scottish Funding Council grant HR09011); ELC by a Rutherford Discovery Fellowship from the Royal Society of New Zealand Te Aparangi; NAS by a Ramon y Cajal Fellowship from the Spanish Ministry of Innovation; MLM by the European Union’s Horizon 2020 Research and Innovation Programme (Marie Skłodowska-Curie grant 801199); CR by the Marine Institute (Cetaceans on the Frontier) and the Irish Research Council; and MTO by the Hartmann Foundation.The deep sea is the largest ecosystem on Earth, yet little is known about the processes driving patterns of genetic diversity in its inhabitants. Here, we investigated the macro- and microevolutionary processes shaping genomic population structure and diversity in two poorly understood, globally distributed, deep-sea predators: Cuvier’s beaked whale (Ziphius cavirostris) and Blainville’s beaked whale (Mesoplodon densirostris). We used double-digest restriction associated DNA (ddRAD) and whole mitochondrial genome (mitogenome) sequencing to characterise genetic patterns using phylogenetic trees, cluster analysis, isolation-by-distance, genetic diversity and differentiation statistics. Single nucleotide polymorphisms (SNPs; Blainville’s n = 43 samples, SNPs=13988; Cuvier’s n = 123, SNPs= 30479) and mitogenomes (Blainville’s n = 27; Cuvier’s n = 35) revealed substantial hierarchical structure at a global scale. Both species display significant genetic structure between the Atlantic, Indo-Pacific and in Cuvier’s, the Mediterranean Sea. Within major ocean basins, clear differentiation is found between genetic clusters on the east and west sides of the North Atlantic, and some distinct patterns of structure in the Indo-Pacific and Southern Hemisphere. We infer that macroevolutionary processes shaping patterns of genetic diversity include biogeographical barriers, highlighting the importance of such barriers even to highly mobile, deep-diving taxa. The barriers likely differ between the species due to their thermal tolerances and evolutionary histories. On a microevolutionary scale, it seems likely that the balance between resident populations displaying site fidelity, and transient individuals facilitating gene flow, shapes patterns of connectivity and genetic drift in beaked whales. Based on these results, we propose management units to facilitate improved conservation measures for these elusive species.Publisher PDFPeer reviewe

Biogeography in the deep: hierarchical population genomic structure of two beaked whale species

The deep sea is the largest ecosystem on Earth, yet little is known about the processes driving patterns of genetic diversity in its inhabitants. Here, we investigated the macro- and microevolutionary processes shaping genomic population structure and diversity in two poorly understood, globally distributed, deep-sea predators: Cuvier’s beaked whale (Ziphius cavirostris) and Blainville’s beaked whale (Mesoplodon densirostris). We used double-digest restriction associated DNA (ddRAD) and whole mitochondrial genome (mitogenome) sequencing to characterise genetic patterns using phylogenetic trees, cluster analysis, isolation-by-distance, genetic diversity and differentiation statistics. Single nucleotide polymorphisms (SNPs; Blainville’s n=43 samples, SNPs=13988; Cuvier’s n=123, SNPs= 30479) and mitogenomes (Blainville’s n=27; Cuvier’s n=35) revealed substantial hierarchical structure at a global scale. Both species display significant genetic structure between the Atlantic, Indo-Pacific and in Cuvier’s, the Mediterranean Sea. Within major ocean basins, clear differentiation is found between genetic clusters on the east and west sides of the North Atlantic, and some distinct patterns of structure in the Indo-Pacific and Southern Hemisphere. We infer that macroevolutionary processes shaping patterns of genetic diversity include biogeographical barriers, highlighting the importance of such barriers even to highly mobile, deep-diving taxa. The barriers likely differ between the species due to their thermal tolerances and evolutionary histories. On a microevolutionary scale, it seems likely that the balance between resident populations displaying site fidelity, and transient individuals facilitating gene flow, shapes patterns of connectivity and genetic drift. Based on these results, we propose management units to facilitate improved conservation measures for these elusive species

Worldwide population structure in Cuvier's beaked whales: identification of units for conservation

Small bone samples from over 500 Cuvier's beaked whales (Ziphius cavirostris) representing populations worldwide were collected from museums and other institutions. Genetic analysis of mitochondrial DNA (mtDNA) control region and cytochrome b diversity is underway. These data will be used for a robust statistical assessment of genetic differentiation between populations at regional and ocean basin levels and estimation of rates of dispersal, allowing units for conservation to be identified. Information on the mtDNA haplotype and sex of each specimen will also be provided. Preliminary median-spanning network reconstructions and analyses of molecular variance (AMOVA) for a subset of samples (control region--317 base pairs, n = 219; cytochrome b--326 base pairs, n = 190) revealed strong differentiation among the three ocean basins (North Atlantic, North Pacific, and Southern Hemisphere) at the haplotype and nucleotide level (p < 0.0001). There is also possible evidence of historical movements of these whales between the Atlantic and Pacific Oceans prior to the closure of the Isthmus of Panama approximately 3 million years ago. DNA extraction and sequencing are ongoing. The final deliverables for these contracts are expected in approximately 6 months' time.JG133F05SE6342, JG133F07SE2186

BakerCScottFisheriesWildlifeResurrectionMesoplodonHotaula_FiguresS1-S6.docx

We present genetic and morphological evidence supporting the recognition of a previously synonymized species of Mesoplodon beaked whale in the tropical Indo-Pacific, Mesoplodon hotaula. Although the new species is closely-related to the rare ginkgo-toothed beaked whale M. ginkgodens, we show that these two lineages can be differentiated by maternally (mitochondrial DNA), biparentally (autosomal), and paternally (Y chromosome) inherited DNA sequences, as well as by morphological features. The reciprocal monophyly of the mtDNA genealogies and the largely parapatric distribution of these lineages is consistent with reproductive isolation. The new lineage is currently known from at least seven specimens: Sri Lanka (1), Gilbert Islands, Republic of Kiribati (1+), Palmyra Atoll, Northern Line Islands, U.S.A. (3), Maldives (1), and Seychelles (1). The type specimen (Sri Lanka) was described as a new species, M. hotaula, in 1963, but later synonymized with M. ginkgodens. This discovery brings the total number of Mesoplodon species to 15, making it, by far, the most speciose yet least known genus of cetaceans.Keywords: Speciation, Mesoplodon, Species delimitation, mtDNA, Y-chromosome, Nuclear introns, Taxonomy, Morphology, Beaked whaleKeywords: Speciation, Mesoplodon, Species delimitation, mtDNA, Y-chromosome, Nuclear introns, Taxonomy, Morphology, Beaked whal

BakerCScottFisheriesWildlifeResurrectionMesoplodonHotaula_TablesS1-S5.docx

We present genetic and morphological evidence supporting the recognition of a previously synonymized species of Mesoplodon beaked whale in the tropical Indo-Pacific, Mesoplodon hotaula. Although the new species is closely-related to the rare ginkgo-toothed beaked whale M. ginkgodens, we show that these two lineages can be differentiated by maternally (mitochondrial DNA), biparentally (autosomal), and paternally (Y chromosome) inherited DNA sequences, as well as by morphological features. The reciprocal monophyly of the mtDNA genealogies and the largely parapatric distribution of these lineages is consistent with reproductive isolation. The new lineage is currently known from at least seven specimens: Sri Lanka (1), Gilbert Islands, Republic of Kiribati (1+), Palmyra Atoll, Northern Line Islands, U.S.A. (3), Maldives (1), and Seychelles (1). The type specimen (Sri Lanka) was described as a new species, M. hotaula, in 1963, but later synonymized with M. ginkgodens. This discovery brings the total number of Mesoplodon species to 15, making it, by far, the most speciose yet least known genus of cetaceans.Keywords: Speciation, Species delimitation, Taxonomy, Nuclear introns, Y-chromosome, Morphology, Mesoplodon, Beaked whale, mtDNAKeywords: Speciation, Species delimitation, Taxonomy, Nuclear introns, Y-chromosome, Morphology, Mesoplodon, Beaked whale, mtDNAKeywords: Speciation, Species delimitation, Taxonomy, Nuclear introns, Y-chromosome, Morphology, Mesoplodon, Beaked whale, mtDNAKeywords: Speciation, Species delimitation, Taxonomy, Nuclear introns, Y-chromosome, Morphology, Mesoplodon, Beaked whale, mtDN

Cetacean records from Tristan da Cunha, South Atlantic

The cetacean fauna at the Tristan da Cunha archipelago has been assessed from ship-based, aerial and land-based observations from 1983–2000, from strandings on Tristan da Cunha and Inaccessible Island between 1983 and 1995, and from whaling catch data from 1934–1967. Five species (Eubalaena australis, Megaptera novaeangliae, Tasmacetus shepherdi, Globicephala melas and Orcinus orca) have been sighted within the territorial waters of the archipelago, eight species (Balaenoptera physalus, B. borealis, B. acutorostrata/bonaerensis, Physeter macrocephalus, Mesoplodon mirus, M. bowdoini, Delphinus sp. and Lissodelphis peronii) have been seen or taken within 200 nautical miles (360 km) of the group or have been found stranded on its shores, while another two species (Caperea marginata and Lagenorhynchus obscurus) have been recorded close enough to be considered likely to occur within 200 nautical miles. The records of Mesoplodon mirus and M. bowdoini represent significant extensions to their known distribution. Apart from its possible importance as a mid-oceanic nursery area for southern right whales, the waters of the Tristan Archipelago seem to be a concentration area for T. shepherdi, one of the least-known of the world’s cetaceans