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 ...

Four fin whale sub-species are currently considered valid: Balaenoptera physalus physalus in the North Atlantic, B. p. velifera in the North Pacific, B. p. quoyi and B. p. patachonica in the Southern Hemisphere. The last, not genetically validated, was described as a pygmy-type sub-species, found in low to mid latitudes of the Southern Hemisphere. Genetic analyses across hemispheres show strong phylogeographic structure, yet low geographic coverage in middle latitudes of the Southern Hemisphere impeded an assessment within the area, as well as evaluating the validity of B. p. patachonica. New mtDNA sequences from the Southeastern Pacific allowed an improved coverage of the species’ distribution. Our phylogenetic analyses showed three main lineages and contrasting phylogeographic patterns between Northern and Southern Hemispheres. Absence of recurrent female mediated gene flow between hemispheres was found; however, rare dispersal events revealing old migrations were noted. The absence of genetic structure suggests the existence of one single taxa within the Southern Hemisphere. Thus, until further evidence supporting this subspecies can be produced, such as genetic, ecological, behavioral, or morphological data, we propose that all fin whales from the Southern Hemisphere, including those from middle latitudes of the Southeastern Pacific belong to B. p. quoyi subspecies. This information is important for the current assessment of fin whales, contributing to the evaluation of the taxonomic classification and the conservation of the species.

Commerson’s dolphins (Cephalorhynchus commersonii) are separated into the subspecies C. c. commersonii, found along southern South America (SA) and the Falkland Islands/Islas Malvinas (FI/IM), and C. c. kerguelenensis, restricted to the subantarctic Kerguelen Islands (KI). Following the dispersal model proposed for the genus, the latter is thought to have originated from SA after a long-distance dispersal event. To evaluate this biogeographic scenario, a distribution-wide, balanced sampling of mitochondrial DNA (mtDNA) control region sequences was designed. New tissue samples from southern Chile, Argentina, FI/IM, and KI were added to published sequences from SA and KI, for a total of 256 samples. Genetic diversity indices, genetic and phylogeographic structure, and migration rates were calculated. One haplotype was shared between subspecies, with which all haplotypes of C. c. kerguelenensis formed a distinct group in the haplotype network. A new haplotype for C. c. kerguelenensis is reported. Differentiation in haplotype frequencies was found among localities within the distribution of C. c. commersonii, yet the phylogeographic signal was only statistically significant between subspecies. Coalescent-based historical gene flow estimations indicated migration between the northern and southern portions of the species’ range in SA as well as between SA and the FI/IM, but not between these and the KI. The net nucleotide divergence between dolphins from SA and the FI/IM was lower than the recommended threshold value suggested for delimiting subspecies, unlike that found between C. c. commersonii and C. c. kerguelenensis. The results are consistent with the model of post-glacial colonization of KI by South American C. commersonii, followed by an ongoing divergence process and subspecies status. Thus, C. c. kerguelenensis may represent the most recent diversification step of Cephalorhynchus, where isolation from their source population is driving a process of incipient speciation.

Acoustic telemetry has helped overcome many of the challenges faced when studying the movement ecology of aquatic species, allowing to obtain unprecedented amounts of data. This has made it into one of the most widely used methods nowadays. Many ways to analyse acoustic telemetry data have been made available and deciding on how to analyse the data requires considering the type of research objectives, relevant properties of the data (e.g., resolution, study design, equipment), habits of the study species, researcher experience, among others. To ease this decision process, here we showcase (1) some of the methods used to estimate pseudo-positions and positions from raw acoustic telemetry data, (2) methods to estimate residency and (3) methods to estimate two-dimensional home and occurrence range using geometric or hull-based methods and density-distribution methods, a network-based approach, and three-dimensional methods. We provide examples of some of these were tested using a sample of real data. With this we intend to provide the necessary background for the selection of the method(s) that better fit specific research objectives when using acoustic telemetry.

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1. The sei whale (Balaenoptera borealis) presents a disjointed geographic distribution.Significant genetic divergence between sei whales from the North Atlantic (NA) and North Pacific (NP) have been recorded; however, limited samples from the Southern Hemisphere (SH) have precluded a global analysis.2. The largest recorded mass mortality event occurred in Golfo de Penas, southern Chile, providing a primary source of SH samples. A global mitochondrial DNA phylogeographic study was undertaken including 111 SH samples (98 from Golfo de Penas), and new sequences from the NP.3. A marked phylogeographic structure was observed between the three ocean basins' populations, with the highest Φ ST values between NA-NP and NA-SH, and a lower but still significant value between SH-NP. This structure, and the haplotype distribution pattern, suggest a more recent separation between SH-NP and an absence of recurrent gene flow among all three populations. Only one potential migratory event was detected from SH to NA. 4. These results support an ongoing phylogeographic differentiation between all populations, highlighting the identity of each and the importance of independent management. Therefore, each population should represent a separate management unit, which is important in the development of conservation strategies. Demographic analyses detected a recent reduction of population size in the SHand NA, but not in the NP. For all populations, estimated effective population sizes were higher than estimated census sizes. This suggests that most of the genetic diversity of pre-whaling populations is still retained; however, continued reduction in population sizes could lead to future loss of genetic diversity.6. This study highlights the necessity of local protection and systematic monitoring of the Golfo de Penas sei whale population. In such a remote area the use of remote sensing techniques could be a cost-effective option for evaluating the threat, periodicity and magnitude of mortalities and their effect on the local whale population. The integration of genetic and demographic approaches improves the understanding of the dynamics of populations, which is particularly useful in endangered species.

Cetacean strandings are a valuable source of information for several studies from species richness to conservation and management. During the examination of strandings, taxonomic and sex identification might be hindered for several reasons. Molecular techniques are valuable tools to obtain that missing information. This study evaluates how gene fragment amplification protocols can support the records of strandings done in the field in Chile by identifying, corroborating, or correcting the identification of the species and sex of the recorded individuals. Through a collaboration between a scientific laboratory and government institution in Chile, 63 samples were analyzed. Thirty-nine samples were successfully identified to the species level. In total, 17 species of six families were detected, including six species of conservation interest. Of the 39 samples, 29 corresponded to corroborations of field identifications. Seven corresponded to unidentified samples and three to corrected misidentifications, adding up to 28% of the identified samples. Sex was successfully identified for 58 of the 63 individuals. Twenty were corroborations, 34 were previously unidentified, and four were corrections. Applying this method improves the stranding database of Chile and provides new data for future management and conservation tasks.