8 research outputs found

    Genetic diversity and connectivity of southern right whales (Eubalaena australis) found in the Brazil and Chile-Peru wintering grounds and the South Georgia (Islas Georgias del Sur) feeding ground

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    As species recover from exploitation, continued assessments of connectivity and population structure are warranted to provide information for conservation and management. This is particularly true in species with high dispersal capacity, such as migratory whales, where patterns of connectivity could change rapidly. Here we build on a previous long-term, large-scale collaboration on southern right whales (Eubalaena australis) to combine new (nnew) and published (npub) mitochondrial (mtDNA) and microsatellite genetic data from all major wintering grounds and, uniquely, the South Georgia (Islas Georgias del Sur: SG) feeding grounds. Specifically, we include data from Argentina (npub mtDNA/microsatellite=208/46), Brazil (nnew mtDNA/microsatellite=50/50), South Africa (nnew mtDNA/microsatellite=66/77, npub mtDNA/microsatellite=350/47), Chile-Peru (nnew mtDNA/microsatellite=1/1), the Indo-Pacific (npub mtDNA/microsatellite=769/126), and SG (npub mtDNA/microsatellite=8/0, nnew mtDNA/microsatellite=3/11) to investigate the position of previously unstudied habitats in the migratory network: Brazil, SG and Chile-Peru. These new genetic data show connectivity between Brazil and Argentina, exemplified by weak genetic differentiation and the movement of one genetically identified individual between the South American grounds. The single sample from Chile-Peru had a mtDNA haplotype previously only observed in the Indo-Pacific and had a nuclear genotype that appeared admixed between the Indo-Pacific and South Atlantic, based on genetic clustering and assignment algorithms. The SG samples were clearly South Atlantic, and were more similar to the South American than the South African wintering grounds. This study highlights how international collaborations are critical to provide context for emerging or recovering regions, like the SG feeding ground, as well as those that remain critically endangered, such as Chile-Peru

    A deep learning approach to photo–identification demonstrates high performance on two dozen cetacean species

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    We thank the countless individuals who collected and/or processed the nearly 85,000 images used in this study and those who assisted, particularly those who sorted these images from the millions that did not end up in the catalogues. Additionally, we thank the other Kaggle competitors who helped develop the ideas, models and data used here, particularly those who released their datasets to the public. The graduate assistantship for Philip T. Patton was funded by the NOAA Fisheries QUEST Fellowship. This paper represents HIMB and SOEST contribution numbers 1932 and 11679, respectively. The technical support and advanced computing resources from University of Hawaii Information Technology Services—Cyberinfrastructure, funded in part by the National Science Foundation CC* awards # 2201428 and # 2232862 are gratefully acknowledged. Every photo–identification image was collected under permits according to relevant national guidelines, regulation and legislation.Peer reviewedPublisher PD

    Status of blue whales off Isla de Chiloe, Chile, during 2007 field season

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    Since 2004, a collaborative research program of the Alfaguara Project on blue whales off Isla de Chiloe, Chile, has produce important new information on present day conservation status of this population. This paper presents preliminary findings from 2007 and compares such data with that reported in previous years. Land-based monitoring in 2007 resulted in 36 days of observations with 262.85 h of land-based effort. The maximum number of individuals sighted from land ranged from 2 to 44, with an average of 18.14 individuals per day (SD=12.00 ; CI95% =14.08 - 22.20). Preliminary results on fifteen of seventeen photo-identification surveys conducted in 2007 resulted in the documentation of 123 blue whale groups comprising 156 individuals. The number of whales encountered does not include animals resighted on same day. Individual photo-identification of left and right side respectively, resulted in 80 individual blue whales, including seven between years and sixteen within year recaptures; and 74 individual blue whales, including nine between years and fourteen within year recaptures. The combined photo-identification catalogue (2004-2007) is comprised of 143 individual blue whales (left-side) and 137 (right-side). A photo-identification recapture from different areas provides evidence that the blue whale feeding ground off southern Chile is extensive and dynamic. A recapture analysis of 2005 and 2006 whales shows an overall return rate of 10.8% (left side) and 11.4% (right side) highlighting the northwestern Isla de Chiloe as an important long-term feeding area for this population. Of the 80 individuals recorded this season, 56.8% (n=42) were recorded to be “skinny”, including 5.4% (n=4) with ribs clearly visible. The 2007 proportions of skinny whales are the highest documented to date. It is unknown if these skinny whales represents any potential threat to this population. Therefore, it is essential that long-term photo-identification research continue to monitor this condition

    Preliminary report on the photo-identification of blue whales off Isla de Chiloé, Chile from 2004 to 2006

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    Photo identification of individual blue whales during summer and autumn off the northwestern Isla de Chiloé, southern Chile, were collected from marine surveys conducted from 2004 to 2006. Re-sightings of individual whales both within and between years may provide evidence of residency and site fidelity by blue whales in the area. These records further document the importance of the northwestern Isla de Chiloé as a feeding area for blue whales. These records also highlight the necessity of further comparisons with photographic catalogues from other areas in southern Chile, off the northwestern coast of South America and the Pacific coast of Central America to better understand seasonal movements, distribution of individuals along the eastern South Pacific, and their wintering areas

    COASTAL MIGRATORY CONNECTIONS OF HUMPBACK WHALES, MEGAPTERA NOVAEANGLIAE BOROWSKI, 1781, IN SOUTHERN CHILE

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    There is not published information on a comparative analysis about interchange of individual humpback whales between coastal areas of aggregation of the species along southern Chilean coast. Here we present a comparison of individually photo-identified humpback whales obtained off northwestern Chiloé Island, in Patagonian and Fuegian fjords and in the Strait of Magellan near Carlos III Island , to discover movements and interchange of individuals. Comparison of photographs resulted in conclusive matches of four individuals within the four study locations: two whales from Canal Wide (49°55'S, 74°30'W), one whale from Canal Cockburn (54°18'S, 72°15'W) and a mother-calf pair off northwestern Chiloé Island matched whales found near Carlos III. The minimum linear distance between these summering locations are approximately 80 km from Canal Cockburn to Carlos III, 540 km from Carlos III to Canal Wide, and 1300 km from Carlos III to northwestern Chiloé Island. The trip from Chiloé Island to Strait of Magellan during 38 days in the same summer season represented a minimum mean speed of transit of 34 km/day. This study provides the first evidence of direct connection of individual humpback whales along the coast of southern Chile

    “Type D” killer whale genomes reveal long-term small population size and low genetic diversity

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    Genome sequences can reveal the extent of inbreeding in small populations. Here, we present the first genomic characterization of type D killer whales, a distinctive eco/morphotype with a circumpolar, subantarctic distribution. Effective population size is the lowest estimated from any killer whale genome and indicates a severe population bottleneck. Consequently, type D genomes show among the highest level of inbreeding reported for any mammalian species (FROH ≥ 0.65). Detected recombination cross-over events of different haplotypes are up to an order of magnitude rarer than in other killer whale genomes studied to date. Comparison of genomic data from a museum specimen of a type D killer whale that stranded in New Zealand in 1955, with 3 modern genomes from the Cape Horn area, reveals high covariance and identity-by-state of alleles, suggesting these genomic characteristics and demographic history are shared among geographically dispersed social groups within this morphotype. Limitations to the insights gained in this study stem from the nonindependence of the 3 closely related modern genomes, the recent coalescence time of most variation within the genomes, and the nonequilibrium population history which violates the assumptions of many model-based methods. Long-range linkage disequilibrium and extensive runs of homozygosity found in type D genomes provide the potential basis for both the distinctive morphology, and the coupling of genetic barriers to gene flow with other killer whale populations
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