Global phylogeography and genetic diversity of the long-finned pilot whale Globicephala melas, with new data from the southeastern Pacific

Abstract

The matrilineal long-finned pilot whale presents an antitropical distribution and is divided into two subspecies, one in the temperate seas of the Southern Hemisphere and the other restricted to the north Atlantic and Mediterranean. Until now, population genetic and phylogeographic studies have included localities of most of its Northern Hemisphere distribution, while only the southwestern Pacific has been sampled in the Southern Hemisphere. We add new genetic data from the southeastern Pacific to the published sequences. Low mitochondrial and nuclear diversity was encountered in this new area, as previously reported for other localities. four haplotypes were found with only one new for the species. fifteen haplotypes were detected in the global dataset, underlining the species' low diversity. As previously reported, the subspecies shared two haplotypes and presented a strong phylogeographic structure. the extant distribution of this species has been related to dispersal events during the Last Glacial Maximum. Using the genetic data and Approximate Bayesian calculations, this study supports this historical biogeographic scenario. from a taxonomic perspective, even if genetic analyses do not support the subspecies category, this study endorses the incipient divergence process between hemispheres, thus maintaining their status and addressing them as Demographically independent populations is recommended. Cetaceans have a diverse-and many times contrasting-array of geographic distributions. Some of the widest ranging species include the cosmopolitan sperm whale Physeter macrocephalus 1 and the orca Orcinus orca 2. Other species, especially small-sized odontocetes, generally present coastal and more restricted distributions, like the extreme case of the vaquita, Phocoena sinus 3. Some cetaceans have a particular distribution pattern known as disjunct or antitropical, in which the taxon is present at high latitudes in both hemispheres while being absent from lower latitudes 4. Examples include the mysticete genus Eubalaena, with E. borealis inhabiting the North Pacific, E. japonica the North Atlantic and their austral equivalent in the Southern Hemisphere, E. australis 5. The phocoenid species pair Phocoena phocoena and P. spinipinnis is another example, found in the Northern Hemisphere and the coasts of South America, respectively 6. Among delphinids, the two Lissodelphis species also present this antitropical distribution pattern; L. peronii is present around the Southern Hemisphere, while L. borealis is found in the North Pacific 7. A similar antitropical distribution is presented by the two subspecies of long-finned pilot whales Globicephala melas, where G. m. edwardii inhabits the temperate to subpolar waters of the Southern Hemisphere, while G. m. melas is restricted to the North Atlantic 8. Extinct populations of long-finned pilot whales have been reported in the North Pacific, from Japan 9 and Alaska 10 , dating back 8 000-12 000 years and 2 500-3 500 years, respectively 9,10. Pilot whales are a highly social ...

Sharp decreases in survival probabilities in the long-finned pilot whales in Strait of Gibraltar

“…The different populations of the Mediterranean share common ancestors, but genetic distances indicate that the Strait of Gibraltar population differs from other Mediterranean populations, showing a very low rate of recent migration (Verborgh 2015;Kraft et al 2020).…”

“…One of these resident species is the long-finned pilot whale, Globicephala melas (de Stephanis et al 2008a). The matrilineal long-finned pilot whale is divided into two subspecies, one in the temperate seas of the Southern Hemisphere and the other restricted to the North Atlantic Ocean and Mediterranean, and a strong genetic differentiation is observed between the North Atlantic and Mediterranean populations (Kraft et al 2020). Long-finned pilot whales are protected in the ACCOBAMS agreement (http:// www.…”

Research on whales, dolphins, and porpoises

“…Phylogeographic studies may help us identify the key factors driving genetic evolution of extant species, and thus improve our understanding of their population history and taxonomic classification (Gagnaire 2020;Kraft et al 2020). In this volume, Zhao et al (2021)…”

New haplotypes found in stranded long‐finned pilot whales (Globicephala melas) in the eastern North Atlantic and adjacent waters

“…Until 2018, long‐finned pilot whales were classified on the IUCN red list as “data deficient” and despite reclassification to “least concern,” knowledge of population distribution and trends is scarce, requiring further research to bolster our understanding of the conservation needs of this species (Minton et al, 2018). Previous mitochondrial (mtDNA) studies of long‐finned pilot whales report haplotype diversity for a 345 bp fragment of the control region (CR) to be generally low worldwide, with only 17 haplotypes recorded (Kraft et al, 2020; Monteiro et al, 2015; Oremus et al, 2009). This is lower than haplotype numbers reported in other worldwide studies of cetaceans with comparable social structure (Alexander et al, 2016; Hoelzel et al, 2002; Morin et al, 2010).…”

“…This is lower than haplotype numbers reported in other worldwide studies of cetaceans with comparable social structure (Alexander et al, 2016; Hoelzel et al, 2002; Morin et al, 2010). Across the Southern Hemisphere, 13 of the known 17 345 bp mtDNA CR haplotypes have been recorded (Kraft et al, 2020; Oremus et al, 2009). Only seven of the 17 345 bp mtDNA CR haplotypes have been recorded in the North Atlantic, of which four are not shared with the Southern Hemisphere (Monteiro et al, 2015; Oremus et al, 2009; Sabatier et al, 2015; Siemann, 1994).…”