Leslie Matthew S.

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Leslie
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Matthew S.
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  • Article
    Body size data collected non-invasively from drone images indicate a morphologically distinct Chilean blue whale (Blaenoptera musculus) taxon
    (Inter Research, 2020-11-05) Leslie, Matthew S. ; Perkins-Taylor, Colin M. ; Durban, John W. ; Moore, Michael J. ; Miller, Carolyn A. ; Chanarat, Proud ; Bahamonde, Paulina A. ; Chiang, Gustavo ; Apprill, Amy
    The blue whale Balaenoptera musculus (Linnaeus, 1758) was the target of intense commercial whaling in the 20th century, and current populations remain drastically below pre-whaling abundances. Reducing uncertainty in subspecific taxonomy would enable targeted conservation strategies for the recovery of unique intraspecific diversity. Currently, there are 2 named blue whale subspecies in the temperate to polar Southern Hemisphere: the Antarctic blue whale B. m. intermedia and the pygmy blue whale B. m. brevicauda. These subspecies have distinct morphologies, genetics, and acoustics. In 2019, the Society for Marine Mammalogy’s Committee on Taxonomy agreed that evidence supports a third (and presently unnamed) subspecies of Southern Hemisphere blue whale subspecies, the Chilean blue whale. Whaling data indicate that the Chilean blue whale is intermediate in body length between pygmy and Antarctic blue whales. We collected body size data from blue whales in the Gulfo Corcovado, Chile, during the austral summers of 2015 and 2017 using aerial photogrammetry from a remotely controlled drone to test the hypothesis that the Chilean blue whale is morphologically distinct from other Southern Hemisphere blue whale subspecies. We found the Chilean whale to be morphologically intermediate in both overall body length and relative tail length, thereby joining other diverse data in supporting the Chilean blue whale as a unique subspecific taxon. Additional photogrammetry studies of Antarctic, pygmy, and Chilean blue whales will help examine unique morphological variation within this species of conservation concern. To our knowledge, this is the first non-invasive small drone study to test a hypothesis for systematic biology.
  • Article
    Marine mammal skin microbiotas are influenced by host phylogeny
    (The Royal Society, 2020-05-20) Apprill, Amy ; Miller, Carolyn A. ; Van Cise, Amy M. ; U'Ren, Jana M. ; Leslie, Matthew S. ; Weber, Laura ; Baird, Robin W. ; Robbins, Jooke ; Landry, Scott ; Bogomolni, Andrea L. ; Waring, Gordon T.
    Skin-associated microorganisms have been shown to play a role in immune function and disease of humans, but are understudied in marine mammals, a diverse animal group that serve as sentinels of ocean health. We examined the microbiota associated with 75 epidermal samples opportunistically collected from nine species within four marine mammal families, including: Balaenopteridae (sei and fin whales), Phocidae (harbour seal), Physeteridae (sperm whales) and Delphinidae (bottlenose dolphins, pantropical spotted dolphins, rough-toothed dolphins, short-finned pilot whales and melon-headed whales). The skin was sampled from free-ranging animals in Hawai‘i (Pacific Ocean) and off the east coast of the United States (Atlantic Ocean), and the composition of the bacterial community was examined using the sequencing of partial small subunit (SSU) ribosomal RNA genes. Skin microbiotas were significantly different among host species and taxonomic families, and microbial community distance was positively correlated with mitochondrial-based host genetic divergence. The oceanic location could play a role in skin microbiota variation, but skin from species sampled in both locations is necessary to determine this influence. These data suggest that a phylosymbiotic relationship may exist between microbiota and their marine mammal hosts, potentially providing specific health and immune-related functions that contribute to the success of these animals in diverse ocean ecosystems.
  • Article
    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
    (Oxford University Press, 2020-04-29) Carroll, Emma ; Ott, Paulo H. ; McMillan, Louise F. ; Galletti Vernazzani, Bárbara ; Neveceralova, Petra ; Vermeulen, Els ; Gaggiotti, Oscar E. ; Andriolo, Artur ; Baker, C. Scott ; Bamford, Connor ; Best, Peter B. ; Cabrera, Elsa ; Calderan, Susannah ; Chirife, Andrea ; Fewster, Rachel M. ; Flores, Paulo A. C. ; Frasier, Timothy ; Freitas, Thales R. O. ; Groch, Karina ; Hulva, Pavel ; Kennedy, Amy S. ; Leaper, Russell ; Leslie, Matthew S. ; Moore, Michael J. ; Oliveira, Larissa ; Seger, Jon ; Stepien, Emilie N. ; Valenzuela, Luciano ; Zerbini, Alexandre N. ; Jackson, Jennifer A.
    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 1 genetically identified individual between the South American grounds. The single sample from Chile–Peru had an 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.
  • Article
    Have whales returned to a historical hotspot of industrial whaling? the pattern of southern right whale Eubalaena australis recovery at South Georgia
    (Inter Research, 2020-11-05) Jackson, Jennifer A. ; Kennedy, Amy S. ; Moore, Michael J. ; Andriolo, Artur ; Bamford, Connor C. G. ; Calderan, Susannah ; Cheeseman, Ted ; Gittins, George ; Groch, Karina ; Kelly, Natalie ; Leaper, Russell ; Leslie, Matthew S. ; Lurcock, Sarah ; Miller, Brian S. ; Richardson, Jessica ; Rowntree, Victoria ; Smith, Patrick ; Stepien, Emilie N. ; Stowasser, Gabriele ; Trathan, Phil N. ; Vermeulen, Els ; Zerbini, Alexandre N. ; Carroll, Emma
    Around 176500 whales were killed in the sub-Antarctic waters off South Georgia (South Atlantic) between 1904 and 1965. In recent decades, whales have once again become summer visitors, with the southern right whale (SRW) the most commonly reported species until 2011. Here, we assess the distribution, temporal pattern, health status and likely prey of SRWs in these waters, combining observations from a summertime vessel-based expedition to South Georgia, stable isotope data collected from SRWs and putative prey and sightings reports collated by the South Georgia Museum. The expedition used directional acoustics and visual surveys to localise whales and collected skin biopsies and photo-IDs. During 76 h of visual observation effort over 19 expedition days, SRWs were encountered 15 times (~31 individuals). Photo-IDs, combined with publicly contributed images from commercial vessels, were reconciled and quality-controlled to form a catalogue of 6 fully (i.e. both sides) identified SRWs and 26 SRWs identified by either left or right sides. No photo-ID matches were found with lower-latitude calving grounds, but 3 whales had gull lesions supporting a direct link with Península Valdés, Argentina. The isotopic position of SRWs in the South Georgia food web suggests feeding on a combination of copepod and krill species. Opportunistic reports of SRW sightings and associated group sizes remain steady over time, while humpback whales provide a strong contrast, with increased sighting rates and group sizes seen since 2013. These data suggest a plateau in SRWs and an increasing humpback whale presence in South Georgia waters following the cessation of whaling.
  • Article
    Shaped by their environment: variation in Blue Whale morphology across three productive coastal ecosystems
    (Oxford University Press, 2023-11-20) Barlow, Dawn R. ; Bierlich, Kevin C. ; Oestreich, William K. ; Chiang, Gustavo ; Durban, John W. ; Goldbogen, Jeremy A. ; Johnston, David W. ; Leslie, Matthew S. ; Moore, Michael J. ; Ryan, John P. ; Torres, Leigh G.
    Species ecology and life history patterns are often reflected in animal morphology. Blue whales are globally distributed, with distinct populations that feed in different productive coastal regions worldwide. Thus, they provide an opportunity to investigate how regional ecosystem characteristics may drive morphological differences within a species. Here, we compare physical and biological oceanography of three different blue whale foraging grounds: (1) Monterey Bay, California, USA; (2) the South Taranaki Bight (STB), Aotearoa New Zealand; and (3) the Corcovado Gulf, Chile. Additionally, we compare the morphology of blue whales from these regions using unoccupied aircraft imagery. Monterey Bay and the Corcovado Gulf are seasonally productive and support the migratory life history strategy of the Eastern North Pacific (ENP) and Chilean blue whale populations, respectively. In contrast, the New Zealand blue whale population remains in the less productive STB year-round. All three populations were indistinguishable in total body length. However, New Zealand blue whales were in significantly higher body condition despite lower regional productivity, potentially attributable to their non-migratory strategy that facilitates lower risk of spatiotemporal misalignment with more consistently available foraging opportunities. Alternatively, the migratory strategy of the ENP and Chilean populations may be successful when their presence on the foraging grounds temporally aligns with abundant prey availability. We document differences in skull and fluke morphology between populations, which may relate to different feeding behaviors adapted to region-specific prey and habitat characteristics. These morphological features may represent a trade-off between maneuverability for prey capture and efficient long-distance migration. As oceanographic patterns shift relative to long-term means under climate change, these blue whale populations may show different vulnerabilities due to differences in migratory phenology and feeding behavior between regions.