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Pretorius LE, Bester MN, Connan M, Hofmeyr GJG. Canine morphometrics as a tool for distinguishing species, sex, and age class in Southern Ocean fur seals. J Morphol 2022; 283:1546-1560. [PMID: 36223543 PMCID: PMC9828835 DOI: 10.1002/jmor.21521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 09/14/2022] [Accepted: 10/07/2022] [Indexed: 01/19/2023]
Abstract
Carcasses resulting from natural mortalities are invaluable for use in scientific studies, provided species, sex, and age class are known. When such data are unavailable, identifying skeletal remains is necessary if one is to use the information contained within samples. Teeth are amongst the best preserved skeletal remains owing to the durability of enamel and dentine. Here, we tested whether external measurements of canines could be used to distinguish two partially sympatric species of Southern Ocean fur seals, the Antarctic Arctocephalus gazella and Sub-Antarctic A. tropicalis fur seals. We also investigated whether the external measurements of canines could be used to determine the age, sex, as well as island of origin of the animals. Eight morphological variables (crown length, root length, crown width, root width, crown thickness, root thickness, total canine length, and count of external surface annular ridges) were recorded from canines of 340 individuals of known species, sex, and island of origin. The count of external annular ridges provided a good estimate of age, which was confirmed by counting the growth layer groups of sectioned teeth, especially for older animals (> 9 years old). External canine measurements proved useful in distinguishing species, as well as sex within and between species, particularly in adult animals. Species were more difficult to distinguish in females than in males. The islands of origin could only be inferred in male Antarctic fur seals. This study indicates that fur seal teeth of unknown provenance, found either in breeding colonies or as vagrants, provide evidence on species, sex, and age of the animal, which increases the value of associated samples. It further highlights the importance of external measurements of skeletal remains such as canine teeth in separating closely related species.
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Affiliation(s)
- Liezl E. Pretorius
- Department of Zoology and Entomology, Mammal Research InstituteUniversity of PretoriaPretoriaSouth Africa
| | - Marthán N. Bester
- Department of Zoology and Entomology, Mammal Research InstituteUniversity of PretoriaPretoriaSouth Africa
| | - Maëlle Connan
- Marine Apex Predator Research Unit, Department of Zoology, Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - G. J. Greg Hofmeyr
- Marine Apex Predator Research Unit, Department of Zoology, Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa,Port Elizabeth Museum at BayworldGqeberhaSouth Africa
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2
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Viral metagenomics reveals persistent as well as dietary acquired viruses in Antarctic fur seals. Sci Rep 2022; 12:18207. [PMID: 36307519 PMCID: PMC9616810 DOI: 10.1038/s41598-022-23114-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 10/25/2022] [Indexed: 12/31/2022] Open
Abstract
Viruses linked to animals inhabiting Antarctic latitudes remain poorly studied. Remote environments hosting large pinniped populations may be prone to exposure of immunologically naïve animals to new infectious agents due to increasing human presence or introduction of new animal species. Antarctic fur seals (Arctocephalus gazella) inhabiting the Western Antarctic Peninsula and the South Shetland Islands are challenged because of climate change and increased anthropogenic activity. In the present study, the fecal and serum virome of A. gazella was characterized by applying target enrichment next generation sequencing. The resulting viromes were dominated by CRESS-DNA sequences. Viruses known to infect vertebrate and invertebrate hosts were also observed in fecal samples. Fur seal picornavirus was present in all the fecal pools studied suggesting it is a prevalent virus in these species. Six different viruses presenting similarities with previously described A. gazella viruses or other otariids and mammal viruses were identified as potential new A. gazella viruses. Also, diet-derived viruses such as crustacean viruses were present in fecal content. Penguin viruses, but not fish viruses, were also detected. Obtained results contribute to a better understanding of the viral community present in these species, which is relevant for its conservation.
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3
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Sub-Antarctic fur seal, Arctocephalus tropicalis, crossing hemispheres far offshore at São Pedro and São Paulo archipelago, Brazil. Polar Biol 2022. [DOI: 10.1007/s00300-022-03046-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Demographic Reconstruction of Antarctic Fur Seals Supports the Krill Surplus Hypothesis. Genes (Basel) 2022; 13:genes13030541. [PMID: 35328094 PMCID: PMC8954904 DOI: 10.3390/genes13030541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/10/2022] [Indexed: 11/16/2022] Open
Abstract
Much debate surrounds the importance of top-down and bottom-up effects in the Southern Ocean, where the harvesting of over two million whales in the mid twentieth century is thought to have produced a massive surplus of Antarctic krill. This excess of krill may have allowed populations of other predators, such as seals and penguins, to increase, a top-down hypothesis known as the ‘krill surplus hypothesis’. However, a lack of pre-whaling population baselines has made it challenging to investigate historical changes in the abundance of the major krill predators in relation to whaling. Therefore, we used reduced representation sequencing and a coalescent-based maximum composite likelihood approach to reconstruct the recent demographic history of the Antarctic fur seal, a pinniped that was hunted to the brink of extinction by 18th and 19th century sealers. In line with the known history of this species, we found support for a demographic model that included a substantial reduction in population size around the time period of sealing. Furthermore, maximum likelihood estimates from this model suggest that the recovered, post-sealing population at South Georgia may have been around two times larger than the pre-sealing population. Our findings lend support to the krill surplus hypothesis and illustrate the potential of genomic approaches to shed light on long-standing questions in population biology.
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Elephant seals (Mirounga leonina) at Potter Peninsula, King George Island, Antarctica: genetic variation of the breeding colony and gene flow with other colonies. Polar Biol 2022. [DOI: 10.1007/s00300-021-02996-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Weinberger CS, Vianna JA, Faugeron S, Marquet PA. Inferring the impact of past climate changes and hunting on the South American sea lion. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Constanza S. Weinberger
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Juliana A. Vianna
- Departamento de Ecosistemas y Medio Ambiente Facultad de Agronomía e Ingeniería Forestal Pontifícia Universidad Católica de Chile Santiago Chile
- Centro Cambio Global UC Pontificia Universidad Católica de Chile Santiago Chile
| | - Sylvain Faugeron
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
- IRL3614 Evolutionary Biology and Ecology of Algae CNRS Sorbonne Université Pontificia Universidad Católica de ChileUniversidad Austral de ChileStation Biologique Roscoff France
| | - Pablo A. Marquet
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
- Centro Cambio Global UC Pontificia Universidad Católica de Chile Santiago Chile
- Instituto de Ecología y Biodiversidad (IEB) Santiago Chile
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7
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Cleary AC, Hoffman JI, Forcada J, Lydersen C, Lowther AD, Kovacs KM. 50,000 years of ice and seals: Impacts of the Last Glacial Maximum on Antarctic fur seals. Ecol Evol 2021; 11:14003-14011. [PMID: 34707834 PMCID: PMC8525082 DOI: 10.1002/ece3.8104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/22/2021] [Accepted: 08/26/2021] [Indexed: 11/11/2022] Open
Abstract
Ice is one of the most important drivers of population dynamics in polar organisms, influencing the locations, sizes, and connectivity of populations. Antarctic fur seals, Arctocephalus gazella, are particularly interesting in this regard, as they are concomitantly reliant on both ice-associated prey and ice-free coastal breeding areas. We reconstructed the history of this species through the Last Glacial Maximum (LGM) using genomic sequence data from seals across their range. Population size trends and divergence events were investigated using continuous-time size estimation analysis and divergence time estimation models. The combined results indicated that a panmictic population present prior to the LGM split into two small refugial populations during peak ice extent. Following ice decline, the western refugial population founded colonies at the South Shetlands, South Georgia, and Bouvetøya, while the eastern refugial population founded the colony on Iles Kerguelen. Postglacial population divergence times closely match geological estimates of when these coastal breeding areas became ice free. Given the predictions regarding continued future warming in polar oceans, these responses of Antarctic fur seals to past climate variation suggest it may be worthwhile giving conservation consideration to potential future breeding locations, such as areas further south along the Antarctic Peninsula, in addition to present colony areas.
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Affiliation(s)
- Alison C. Cleary
- Department of Natural SciencesUniversity of AgderKristiansandNorway
- Norwegian Polar InstituteFram CentreTromsøNorway
| | - Joseph I. Hoffman
- Department of Animal BehaviourUniversity of BielefeldBielefeldGermany
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Khoyetskyy P. The status of the fur seal population (Arctocephalus gazelle) on the southern border of the distribution area (the Argentine Islands archipelago). THERIOLOGIA UKRAINICA 2021. [DOI: 10.15407/tu2115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The study of the population status of Arctocephalus gazella (Peters, 1875) in waters of the Argentine Islands was carried out in the period from April 2015 to March 2016 in accordance with the objectives of the State Target Scientific and Technical Research Program of Ukraine in Antarctica for 2011–2020. The aim of the article is to study the population dynamics and distribution of the southern fur seal in waters of the Argentine Islands. Due to the lack of data on the specifics of the seal’s dispersal in different periods of the year and the dynamics of the species population at the southern border of the distribution range, the results of the research are relevant and of great importance. In the second half of the 20th century, some publications presented the results of monitoring of pinnipeds at the Argentine Islands and adjacent territories, but the objects of these studies usually were other seal species: Hydrurga leptonyx, Lobodon carcinophagus, Leptonychotes weddelli, and Mirounga leonina. In the early 21st century, monitoring of the fauna of the Argentine Islands was carried out by Ukrainian biologists. However, they focused on Leptonychotes weddelli and less on other species of pinnipeds. The field material was collected in waters of the Argentine Islands, which is located in the Pacific sector of Antarctica. The fur seal population census and distribution studies were conducted according to the generally accepted methods. After breeding season on the subantarctic islands, during the migration southwards, fur seals reach the Argentine Islands, usually in the third decade of January. In the summer of 2016, the first fur seal was recorded within the archipelago on 31 January. During the study period, the largest number of animals within the archipelago was recorded in March–April and it ranged from 300 to 400 individuals. On the islands of the archipelago, the main resting places of seals were identified. The movement of animals northwards starts in May, consequently a decrease in the number of animals in this region is observed at that time. The last individuals are recorded in the first half of August. In 2015, migration began in May and ended in early August. There are several periods that were characterized by intensive migration of the animals: late June, 5–8 July, and 29 July to 6 August. In winter, one individual was last found within the archipelago on 12 August. The migration is launched by the worsening of weather conditions, formation of a continuous ice cover, reduced availability of food, and other factors.
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9
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Paijmans AJ, Stoffel MA, Bester MN, Cleary AC, De Bruyn PJN, Forcada J, Goebel ME, Goldsworthy SD, Guinet C, Lydersen C, Kovacs KM, Lowther A, Hoffman JI. The genetic legacy of extreme exploitation in a polar vertebrate. Sci Rep 2020; 10:5089. [PMID: 32198403 PMCID: PMC7083876 DOI: 10.1038/s41598-020-61560-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/24/2020] [Indexed: 12/12/2022] Open
Abstract
Understanding the effects of human exploitation on the genetic composition of wild populations is important for predicting species persistence and adaptive potential. We therefore investigated the genetic legacy of large-scale commercial harvesting by reconstructing, on a global scale, the recent demographic history of the Antarctic fur seal (Arctocephalus gazella), a species that was hunted to the brink of extinction by 18th and 19th century sealers. Molecular genetic data from over 2,000 individuals sampled from all eight major breeding locations across the species' circumpolar geographic distribution, show that at least four relict populations around Antarctica survived commercial hunting. Coalescent simulations suggest that all of these populations experienced severe bottlenecks down to effective population sizes of around 150-200. Nevertheless, comparably high levels of neutral genetic variability were retained as these declines are unlikely to have been strong enough to deplete allelic richness by more than around 15%. These findings suggest that even dramatic short-term declines need not necessarily result in major losses of diversity, and explain the apparent contradiction between the high genetic diversity of this species and its extreme exploitation history.
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Affiliation(s)
- Anneke J Paijmans
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany.
| | - Martin A Stoffel
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH9 3FL, United Kingdom
| | - Marthán N Bester
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Alison C Cleary
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway
- Department of Natural Sciences, University of Agder, 4630, Kristiansand, Norway
| | - P J Nico De Bruyn
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Jaume Forcada
- British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 OET, UK
| | - Michael E Goebel
- Antarctic Ecosystem Research Division, Southwest Fisheries Science Center, National Marine Fisheries, National Oceanographic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, USA
- Institute of Marine Science, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA
| | - Simon D Goldsworthy
- South Australian Research and Development Institute, 2 Hamra Avenue, West Beach, South Australia, 5024, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé (CEBC), CNRS and Université de La Rochelle - UMR 7372, 79360, Villiers en Bois, France
| | | | - Kit M Kovacs
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway
| | - Andrew Lowther
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway
| | - Joseph I Hoffman
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany.
- British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 OET, UK.
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10
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Rogers AD, Frinault BAV, Barnes DKA, Bindoff NL, Downie R, Ducklow HW, Friedlaender AS, Hart T, Hill SL, Hofmann EE, Linse K, McMahon CR, Murphy EJ, Pakhomov EA, Reygondeau G, Staniland IJ, Wolf-Gladrow DA, Wright RM. Antarctic Futures: An Assessment of Climate-Driven Changes in Ecosystem Structure, Function, and Service Provisioning in the Southern Ocean. ANNUAL REVIEW OF MARINE SCIENCE 2020; 12:87-120. [PMID: 31337252 DOI: 10.1146/annurev-marine-010419-011028] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this article, we analyze the impacts of climate change on Antarctic marine ecosystems. Observations demonstrate large-scale changes in the physical variables and circulation of the Southern Ocean driven by warming, stratospheric ozone depletion, and a positive Southern Annular Mode. Alterations in the physical environment are driving change through all levels of Antarctic marine food webs, which differ regionally. The distributions of key species, such as Antarctic krill, are also changing. Differential responses among predators reflect differences in species ecology. The impacts of climate change on Antarctic biodiversity will likely vary for different communities and depend on species range. Coastal communities and those of sub-Antarctic islands, especially range-restricted endemic communities, will likely suffer the greatest negative consequences of climate change. Simultaneously, ecosystem services in the Southern Ocean will likely increase. Such decoupling of ecosystem services and endemic species will require consideration in the management of human activities such as fishing in Antarctic marine ecosystems.
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Affiliation(s)
- A D Rogers
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom;
- REV Ocean, 1366 Lysaker, Norway
| | - B A V Frinault
- School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, United Kingdom
| | - D K A Barnes
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - N L Bindoff
- Antarctic Climate and Ecosystems Cooperative Research Centre and CSIRO Oceans and Atmospheres, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - R Downie
- WWF, Living Planet Centre, Surrey GU21 4LL, United Kingdom
| | - H W Ducklow
- Lamont-Doherty Earth Observatory and Department of Earth and Environmental Sciences, Columbia University, Palisades, New York 10964-8000, USA
| | - A S Friedlaender
- Institute for Marine Sciences, University of California, Santa Cruz, California 95060, USA
| | - T Hart
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom;
| | - S L Hill
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - E E Hofmann
- Center for Coastal Physical Oceanography, Old Dominion University, Norfolk, Virginia 23508, USA
| | - K Linse
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - C R McMahon
- Integrated Marine Observing System Animal Tracking Facility, Sydney Institute of Marine Science, Sydney, New South Wales 2088, Australia
| | - E J Murphy
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - E A Pakhomov
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Aquatic Ecosystems Research Lab, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - G Reygondeau
- Aquatic Ecosystems Research Lab, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - I J Staniland
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - D A Wolf-Gladrow
- Alfred-Wegener-Institut Helmholtz Zentrum für Polar- und Meeresforschung (AWI), 27570 Bremerhaven, Germany
| | - R M Wright
- Tyndall Centre, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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11
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Rexer-Huber K, Veale AJ, Catry P, Cherel Y, Dutoit L, Foster Y, McEwan JC, Parker GC, Phillips RA, Ryan PG, Stanworth AJ, van Stijn T, Thompson DR, Waters J, Robertson BC. Genomics detects population structure within and between ocean basins in a circumpolar seabird: The white-chinned petrel. Mol Ecol 2019; 28:4552-4572. [PMID: 31541577 DOI: 10.1111/mec.15248] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 08/29/2019] [Accepted: 09/09/2019] [Indexed: 02/06/2023]
Abstract
The Southern Ocean represents a continuous stretch of circumpolar marine habitat, but the potential physical and ecological drivers of evolutionary genetic differentiation across this vast ecosystem remain unclear. We tested for genetic structure across the full circumpolar range of the white-chinned petrel (Procellaria aequinoctialis) to unravel the potential drivers of population differentiation and test alternative population differentiation hypotheses. Following range-wide comprehensive sampling, we applied genomic (genotyping-by-sequencing or GBS; 60,709 loci) and standard mitochondrial-marker approaches (cytochrome b and first domain of control region) to quantify genetic diversity within and among island populations, test for isolation by distance, and quantify the number of genetic clusters using neutral and outlier (non-neutral) loci. Our results supported the multi-region hypothesis, with a range of analyses showing clear three-region genetic population structure, split by ocean basin, within two evolutionary units. The most significant differentiation between these regions confirmed previous work distinguishing New Zealand and nominate subspecies. Although there was little evidence of structure within the island groups of the Indian or Atlantic oceans, a small set of highly-discriminatory outlier loci could assign petrels to ocean basin and potentially to island group, though the latter needs further verification. Genomic data hold the key to revealing substantial regional genetic structure within wide-ranging circumpolar species previously assumed to be panmictic.
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Affiliation(s)
- Kalinka Rexer-Huber
- Department of Zoology, University of Otago, Dunedin, New Zealand.,Parker Conservation, Dunedin, New Zealand
| | - Andrew J Veale
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Paulo Catry
- MARE - Marine and Environmental Sciences Centre, ISPA - Instituto Universitário, Lisboa, Portugal
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-La Rochelle Université, Villiers-en-Bois, France
| | - Ludovic Dutoit
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Yasmin Foster
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - John C McEwan
- Invermay Agricultural Centre, AgResearch, Mosgiel, New Zealand
| | | | - Richard A Phillips
- British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
| | - Peter G Ryan
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
| | | | | | - David R Thompson
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
| | - Jonathan Waters
- Department of Zoology, University of Otago, Dunedin, New Zealand
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12
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Far away from home: presence of fur seal (Arctocephalus sp.) in the equatorial Atlantic Ocean. Polar Biol 2019. [DOI: 10.1007/s00300-019-02461-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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13
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Halanych KM, Mahon AR. Challenging Dogma Concerning Biogeographic Patterns of Antarctica and the Southern Ocean. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2018. [DOI: 10.1146/annurev-ecolsys-121415-032139] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Antarctica is enormous, cold, remote, and particularly sensitive to climate change. Most biological research below 60°S has focused on the isolated nature of the biota and how organisms have adapted to the cold and ice. However, biogeographic patterns in Antarctica and the Southern Ocean, and the processes explaining how those patterns came about, still await adequate explanation. Both terrestrial and marine organisms have been influenced by climatic change (e.g., glaciation), physical phenomena (e.g., oceanic currents), and/or potential barriers to gene flow (e.g., steep thermal gradients). Whereas the Antarctic region contains diverse and complex marine communities, terrestrial systems tend to be comparatively simple with limited diversity. Here, we challenge the current dogma used to explain the diversity and biogeographic patterns present in the Antarctic. We assert that relatively modern processes within the last few million years, rather than geo-logical events that occurred in the Eocene and Miocene, account for present patterns of biodiversity in the region. Additionally, reproductive life history stages appear to have little influence in structuring genetic patterns in the Antarctic, as currents and glacial patterns are noted to be more important drivers of organismal patterns of distribution. Finally, we highlight the need for additional sampling, high-throughput genomic approaches, and broad, multinational cooperation for addressing outstanding questions of Antarctic biogeography and biodiversity.
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Affiliation(s)
- Kenneth M. Halanych
- Molette Biology Laboratory for Environmental and Climate Change Studies, Department of Biological Sciences, Auburn University, Auburn, Alabama 36849, USA
| | - Andrew R. Mahon
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan 48859, USA
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14
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Hoffman JI, Bauer E, Paijmans AJ, Humble E, Beckmann LM, Kubetschek C, Christaller F, Kröcker N, Fuchs B, Moreras A, Shihlomule YD, Bester MN, Cleary AC, De Bruyn PJN, Forcada J, Goebel ME, Goldsworthy SD, Guinet C, Hoelzel AR, Lydersen C, Kovacs KM, Lowther A. A global cline in a colour polymorphism suggests a limited contribution of gene flow towards the recovery of a heavily exploited marine mammal. ROYAL SOCIETY OPEN SCIENCE 2018; 5:181227. [PMID: 30473858 PMCID: PMC6227926 DOI: 10.1098/rsos.181227] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/18/2018] [Indexed: 06/09/2023]
Abstract
Evaluating how populations are connected by migration is important for understanding species resilience because gene flow can facilitate recovery from demographic declines. We therefore investigated the extent to which migration may have contributed to the global recovery of the Antarctic fur seal (Arctocephalus gazella), a circumpolar distributed marine mammal that was brought to the brink of extinction by the sealing industry in the eighteenth and nineteenth centuries. It is widely believed that animals emigrating from South Georgia, where a relict population escaped sealing, contributed to the re-establishment of formerly occupied breeding colonies across the geographical range of the species. To investigate this, we interrogated a genetic polymorphism (S291F) in the melanocortin 1 receptor gene, which is responsible for a cream-coloured phenotype that is relatively abundant at South Georgia and which appears to have recently spread to localities as far afield as Marion Island in the sub-Antarctic Indian Ocean. By sequencing a short region of this gene in 1492 pups from eight breeding colonies, we showed that S291F frequency rapidly declines with increasing geographical distance from South Georgia, consistent with locally restricted gene flow from South Georgia mainly to the South Shetland Islands and Bouvetøya. The S291F allele was not detected farther afield, suggesting that although emigrants from South Georgia may have been locally important, they are unlikely to have played a major role in the recovery of geographically more distant populations.
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Affiliation(s)
- J. I. Hoffman
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET, UK
| | - E. Bauer
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - A. J. Paijmans
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - E. Humble
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - L. M. Beckmann
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - C. Kubetschek
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - F. Christaller
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - N. Kröcker
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - B. Fuchs
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - A. Moreras
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - Y. D. Shihlomule
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - M. N. Bester
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - A. C. Cleary
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
| | - P. J. N. De Bruyn
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - J. Forcada
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET, UK
| | - M. E. Goebel
- Antarctic Ecosystem Research Division, Southwest Fisheries Science Center, National Marine Fisheries, National Oceanographic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA 92037, USA
| | - S. D. Goldsworthy
- South Australian Research and Development Institute, 2 Hamra Avenue, West Beach, South Australia 5024, Australia
| | - C. Guinet
- Centre d'Etudes Biologiques de Chizé (CEBC), CNRS and Université de La Rochelle - UMR 7372, 79360 Villiers en Bois, France
| | - A. R. Hoelzel
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - C. Lydersen
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
| | - K. M. Kovacs
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
| | - A. Lowther
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
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15
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Dussex N, Taylor HR, Stovall WR, Rutherford K, Dodds KG, Clarke SM, Gemmell NJ. Reduced representation sequencing detects only subtle regional structure in a heavily exploited and rapidly recolonizing marine mammal species. Ecol Evol 2018; 8:8736-8749. [PMID: 30271541 PMCID: PMC6157699 DOI: 10.1002/ece3.4411] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/17/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022] Open
Abstract
Next-generation reduced representation sequencing (RRS) approaches show great potential for resolving the structure of wild populations. However, the population structure of species that have shown rapid demographic recovery following severe population bottlenecks may still prove difficult to resolve due to high gene flow between subpopulations. Here, we tested the effectiveness of the RRS method Genotyping-By-Sequencing (GBS) for describing the population structure of the New Zealand fur seal (NZFS, Arctocephalus forsteri), a species that was heavily exploited by the 19th century commercial sealing industry and has since rapidly recolonized most of its former range from a few isolated colonies. Using 26,026 neutral single nucleotide polymorphisms (SNPs), we assessed genetic variation within and between NZFS colonies. We identified low levels of population differentiation across the species range (<1% of variation explained by regional differences) suggesting a state of near panmixia. Nonetheless, we observed subtle population substructure between West Coast and Southern East Coast colonies and a weak, but significant (p = 0.01), isolation-by-distance pattern among the eight colonies studied. Furthermore, our demographic reconstructions supported severe bottlenecks with potential 10-fold and 250-fold declines in response to Polynesian and European hunting, respectively. Finally, we were able to assign individuals treated as unknowns to their regions of origin with high confidence (96%) using our SNP data. Our results indicate that while it may be difficult to detect population structure in species that have experienced rapid recovery, next-generation markers and methods are powerful tools for resolving fine-scale structure and informing conservation and management efforts.
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Affiliation(s)
- Nicolas Dussex
- Department of AnatomyUniversity of OtagoDunedinNew Zealand
- Department of Bioinformatics and GeneticsSwedish Museum of Natural HistoryStockholmSweden
| | | | | | - Kim Rutherford
- Department of AnatomyUniversity of OtagoDunedinNew Zealand
| | - Ken G. Dodds
- Invermay Agricultural CentreAgResearchPuddle AlleyMosgielNew Zealand
| | - Shannon M. Clarke
- Invermay Agricultural CentreAgResearchPuddle AlleyMosgielNew Zealand
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RAD Sequencing and a Hybrid Antarctic Fur Seal Genome Assembly Reveal Rapidly Decaying Linkage Disequilibrium, Global Population Structure and Evidence for Inbreeding. G3-GENES GENOMES GENETICS 2018; 8:2709-2722. [PMID: 29954843 PMCID: PMC6071602 DOI: 10.1534/g3.118.200171] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recent advances in high throughput sequencing have transformed the study of wild organisms by facilitating the generation of high quality genome assemblies and dense genetic marker datasets. These resources have the potential to significantly advance our understanding of diverse phenomena at the level of species, populations and individuals, ranging from patterns of synteny through rates of linkage disequilibrium (LD) decay and population structure to individual inbreeding. Consequently, we used PacBio sequencing to refine an existing Antarctic fur seal (Arctocephalus gazella) genome assembly and genotyped 83 individuals from six populations using restriction site associated DNA (RAD) sequencing. The resulting hybrid genome comprised 6,169 scaffolds with an N50 of 6.21 Mb and provided clear evidence for the conservation of large chromosomal segments between the fur seal and dog (Canis lupus familiaris). Focusing on the most extensively sampled population of South Georgia, we found that LD decayed rapidly, reaching the background level by around 400 kb, consistent with other vertebrates but at odds with the notion that fur seals experienced a strong historical bottleneck. We also found evidence for population structuring, with four main Antarctic island groups being resolved. Finally, appreciable variance in individual inbreeding could be detected, reflecting the strong polygyny and site fidelity of the species. Overall, our study contributes important resources for future genomic studies of fur seals and other pinnipeds while also providing a clear example of how high throughput sequencing can generate diverse biological insights at multiple levels of organization.
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Grandi MF, Loizaga de Castro R, Terán E, Santos MR, Bailliet G, Crespo EA. Is recolonization pattern related to female philopatry? An insight into a colonially breeding mammal. Mamm Biol 2018. [DOI: 10.1016/j.mambio.2017.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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Emami-Khoyi A, Paterson AM, Hartley DA, Boren LJ, Cruickshank RH, Ross JG, Murphy EC, Else TA. Mitogenomics data reveal effective population size, historical bottlenecks, and the effects of hunting on New Zealand fur seals (Arctocephalus forsteri). Mitochondrial DNA A DNA Mapp Seq Anal 2017; 29:567-580. [PMID: 28539070 DOI: 10.1080/24701394.2017.1325478] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The New Zealand fur seal (Arctocephalus forsteri) passed through a population bottleneck due to commercial sealing during the eighteenth to nineteenth centuries. To facilitate future management options, we reconstructed the demographic history of New Zealand fur seals in a Bayesian framework using maternally inherited, mitochondrial DNA sequences. Mitogenomic data suggested two separate clades (most recent common ancestor 5000 years ago) of New Zealand fur seals that survived large-scale human harvest. Mitochondrial haplotype diversity was high, with 45 singletons identified from 46 individuals although mean nucleotide diversity was low (0.012 ± 0.0061). Variation was not constrained geographically. Analyses of mitogenomes support the hypothesis for a population bottleneck approximately 35 generations ago, which coincides with the peak of commercial sealing. Mitogenomic data are consistent with a pre-human effective population size of approximately 30,000 that first declined to around 10,000 (due to the impact of Polynesian colonization, particularly in the first 100 years of their arrival into New Zealand), and then to 100-200 breeding individuals during peak of commercial sealing.
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Affiliation(s)
- Arsalan Emami-Khoyi
- a Center for Ecological Genomics and Wildlife Conservation , University of Johannesburg , Auckland Park , South Africa.,b Department of Ecology , Lincoln University , Lincoln , New Zealand
| | - Adrian M Paterson
- b Department of Ecology , Lincoln University , Lincoln , New Zealand
| | | | - Laura J Boren
- d New Zealand Department of Conservation , Wellington-Te Aro , New Zealand
| | | | - James G Ross
- b Department of Ecology , Lincoln University , Lincoln , New Zealand.,e Centre for Wildlife Management and Conservation , Lincoln University , Lincoln , New Zealand
| | - Elaine C Murphy
- b Department of Ecology , Lincoln University , Lincoln , New Zealand.,e Centre for Wildlife Management and Conservation , Lincoln University , Lincoln , New Zealand
| | - Terry-Ann Else
- f Department of Basic Science , Touro University , NV , USA
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Collins CJ, Chilvers BL, Osborne A, Taylor M, Robertson BC. Unique and isolated: population structure has implications for management of the endangered New Zealand sea lion. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-0969-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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20
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Moon KL, Chown SL, Fraser CI. Reconsidering connectivity in the sub-Antarctic. Biol Rev Camb Philos Soc 2017; 92:2164-2181. [DOI: 10.1111/brv.12327] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 02/09/2017] [Accepted: 02/15/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Katherine L. Moon
- School of Biological Sciences; Monash University; Clayton 3800 Australia
- Fenner School of Environment and Society; Australian National University; Acton 2601 Australia
| | - Steven L. Chown
- School of Biological Sciences; Monash University; Clayton 3800 Australia
| | - Ceridwen I. Fraser
- Fenner School of Environment and Society; Australian National University; Acton 2601 Australia
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21
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Dussex N, Robertson BC, Salis AT, Kalinin A, Best H, Gemmell NJ. Low Spatial Genetic Differentiation Associated with Rapid Recolonization in the New Zealand Fur Seal Arctocephalus forsteri. J Hered 2016; 107:581-592. [PMID: 27563072 DOI: 10.1093/jhered/esw056] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 08/15/2016] [Indexed: 11/14/2022] Open
Abstract
Population declines resulting from anthropogenic activities are of major consequence for the long-term survival of species because the resulting loss of genetic diversity can lead to extinction via the effects of inbreeding depression, fixation of deleterious mutations, and loss of adaptive potential. Otariid pinnipeds have been exploited commercially to near extinction with some species showing higher demographic resilience and recolonization potential than others. The New Zealand fur seal (NZFS) was heavily impacted by commercial sealing between the late 18th and early 19th centuries, but has recolonized its former range in southern Australia. The species has also recolonized its former range in New Zealand, yet little is known about the pattern of recolonization. Here, we first used 11 microsatellite markers (n = 383) to investigate the contemporary population structure and dispersal patterns in the NZFS (Arctocephalus forsteri). Secondly, we model postsealing recolonization with 1 additional mtDNA cytochrome b (n = 261) marker. Our data identified 3 genetic clusters: an Australian, a subantarctic, and a New Zealand one, with a weak and probably transient subdivision within the latter cluster. Demographic history scenarios supported a recolonization of the New Zealand coastline from remote west coast colonies, which is consistent with contemporary gene flow and with the species' high resilience. The present data suggest the management of distinct genetic units in the North and South of New Zealand along a genetic gradient. Assignment of individuals to their colony of origin was limited (32%) with the present data indicating the current microsatellite markers are unlikely sufficient to assign fisheries bycatch of NZFSs to colonies.
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Affiliation(s)
- Nicolas Dussex
- From the Department of Zoology, University of Otago, Dunedin, New Zealand (Dussex, Robertson, and Salis); Allan Wilson Centre, Dunedin, New Zealand (Dussex and Gemmell); Department of Anatomy, University of Otago, PO Box 913, Dunedin 9054, New Zealand (Dussex and Gemmell); School of Biological Sciences, University of Canterbury, Christchurch, New Zealand (Robertson, Kalinin, and Gemmell); and Marine Conservation Unit, Department of Conservation, Wellington, New Zealand (Best)
| | - Bruce C Robertson
- From the Department of Zoology, University of Otago, Dunedin, New Zealand (Dussex, Robertson, and Salis); Allan Wilson Centre, Dunedin, New Zealand (Dussex and Gemmell); Department of Anatomy, University of Otago, PO Box 913, Dunedin 9054, New Zealand (Dussex and Gemmell); School of Biological Sciences, University of Canterbury, Christchurch, New Zealand (Robertson, Kalinin, and Gemmell); and Marine Conservation Unit, Department of Conservation, Wellington, New Zealand (Best)
| | - Alexander T Salis
- From the Department of Zoology, University of Otago, Dunedin, New Zealand (Dussex, Robertson, and Salis); Allan Wilson Centre, Dunedin, New Zealand (Dussex and Gemmell); Department of Anatomy, University of Otago, PO Box 913, Dunedin 9054, New Zealand (Dussex and Gemmell); School of Biological Sciences, University of Canterbury, Christchurch, New Zealand (Robertson, Kalinin, and Gemmell); and Marine Conservation Unit, Department of Conservation, Wellington, New Zealand (Best)
| | - Aleksandr Kalinin
- From the Department of Zoology, University of Otago, Dunedin, New Zealand (Dussex, Robertson, and Salis); Allan Wilson Centre, Dunedin, New Zealand (Dussex and Gemmell); Department of Anatomy, University of Otago, PO Box 913, Dunedin 9054, New Zealand (Dussex and Gemmell); School of Biological Sciences, University of Canterbury, Christchurch, New Zealand (Robertson, Kalinin, and Gemmell); and Marine Conservation Unit, Department of Conservation, Wellington, New Zealand (Best)
| | - Hugh Best
- From the Department of Zoology, University of Otago, Dunedin, New Zealand (Dussex, Robertson, and Salis); Allan Wilson Centre, Dunedin, New Zealand (Dussex and Gemmell); Department of Anatomy, University of Otago, PO Box 913, Dunedin 9054, New Zealand (Dussex and Gemmell); School of Biological Sciences, University of Canterbury, Christchurch, New Zealand (Robertson, Kalinin, and Gemmell); and Marine Conservation Unit, Department of Conservation, Wellington, New Zealand (Best)
| | - Neil J Gemmell
- From the Department of Zoology, University of Otago, Dunedin, New Zealand (Dussex, Robertson, and Salis); Allan Wilson Centre, Dunedin, New Zealand (Dussex and Gemmell); Department of Anatomy, University of Otago, PO Box 913, Dunedin 9054, New Zealand (Dussex and Gemmell); School of Biological Sciences, University of Canterbury, Christchurch, New Zealand (Robertson, Kalinin, and Gemmell); and Marine Conservation Unit, Department of Conservation, Wellington, New Zealand (Best)
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Hoffman JI, Kowalski GJ, Klimova A, Eberhart-Phillips LJ, Staniland IJ, Baylis AMM. Population structure and historical demography of South American sea lions provide insights into the catastrophic decline of a marine mammal population. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160291. [PMID: 27493782 PMCID: PMC4968474 DOI: 10.1098/rsos.160291] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 06/23/2016] [Indexed: 06/06/2023]
Abstract
Understanding the causes of population decline is crucial for conservation management. We therefore used genetic analysis both to provide baseline data on population structure and to evaluate hypotheses for the catastrophic decline of the South American sea lion (Otaria flavescens) at the Falkland Islands (Malvinas) in the South Atlantic. We genotyped 259 animals from 23 colonies across the Falklands at 281 bp of the mitochondrial hypervariable region and 22 microsatellites. A weak signature of population structure was detected, genetic diversity was moderately high in comparison with other pinniped species, and no evidence was found for the decline being associated with a strong demographic bottleneck. By combining our mitochondrial data with published sequences from Argentina, Brazil, Chile and Peru, we also uncovered strong maternally directed population structure across the geographical range of the species. In particular, very few shared haplotypes were found between the Falklands and South America, and this was reflected in correspondingly low migration rate estimates. These findings do not support the prominent hypothesis that the decline was caused by migration to Argentina, where large-scale commercial harvesting operations claimed over half a million animals. Thus, our study not only provides baseline data for conservation management but also reveals the potential for genetic studies to shed light upon long-standing questions pertaining to the history and fate of natural populations.
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Affiliation(s)
- J. I. Hoffman
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
| | - G. J. Kowalski
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
- Animal Ecology Group, Institute of Biochemistry and Biology, University of Potsdam, Maulbeerallee 1, 14469, Potsdam, Germany
| | - A. Klimova
- Centro de Investigaciones Biológicas del Noroeste Baja California Sur, La Paz, Mexico
| | - L. J. Eberhart-Phillips
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
| | - I. J. Staniland
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - A. M. M. Baylis
- South Atlantic Environmental Research Institute, Stanley FIQQ1ZZ, Falkland Islands
- Falklands Conservation, Stanley FIQQ1ZZ, Falkland Islands
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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23
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Corrigan LJ, Fabiani A, Chauke LF, McMahon CR, Bruyn M, Bester MN, Bastos A, Campagna C, Muelbert MMC, Hoelzel AR. Population differentiation in the context of Holocene climate change for a migratory marine species, the southern elephant seal. J Evol Biol 2016; 29:1667-79. [PMID: 27012933 DOI: 10.1111/jeb.12870] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/03/2016] [Accepted: 03/22/2016] [Indexed: 11/30/2022]
Affiliation(s)
- L. J. Corrigan
- School of Biological and Biomedical Sciences Durham University Durham UK
| | - A. Fabiani
- School of Biological and Biomedical Sciences Durham University Durham UK
- Dipartimento di Biologia Università degli Studi di Roma Tor Vergata Roma Italy
- Elephant Seal Research Group Sea Lion Island Falkland Islands
| | - L. F. Chauke
- School of Biological and Biomedical Sciences Durham University Durham UK
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
| | - C. R. McMahon
- Sydney Institute of Marine Science Mosman NSW Australia
| | - M. Bruyn
- School of Biological and Biomedical Sciences Durham University Durham UK
| | - M. N. Bester
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
| | - A. Bastos
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
| | - C. Campagna
- Marine Program Wildlife Conservation Soc Buenos Aires Argentina
| | - M. M. C. Muelbert
- Instituto de Oceanografia Universidade Federal do Rio Grande Rio Grande Brasil
| | - A. R. Hoelzel
- School of Biological and Biomedical Sciences Durham University Durham UK
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Oosthuizen WC, de Bruyn PJN, Wege M, Bester MN. Geographic variation in subantarctic fur seal pup growth: linkages with environmental variability and population density. J Mammal 2015. [DOI: 10.1093/jmammal/gyv181] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Marine predator populations are sensitive to temporal variation in prey availability, but prey dynamics are often difficult to quantify. Long-term measures of offspring growth is a useful performance attribute to gauge the potential demographic direction for such predator populations, especially where other metrics (e.g., population size estimates) are lacking. Subantarctic fur seal ( Arctocephalus tropicalis ) females are central place foragers during a protracted lactation period, and their foraging success determines the growth and vitality of their offspring. Using data spanning over 2 decades, we assessed geographic and temporal variation in growth rates and weaning mass of subantarctic fur seal pups at 2 of the species’ principal populations (Gough and Marion islands) and identified environmental conditions that may, through assumed bottom-up mechanisms, affect body mass at weaning. While Marion Island pups grew at an average rate of between 0.040 and 0.067kg/day early in lactation (comparable to conspecific growth at Amsterdam Island), the mean growth rate at Gough Island (approximately 0.030kg/day) was lower than the growth rate represented by the bottom 5% of the body mass distribution at Marion Island. Notwithstanding substantial interannual variability, we found support for a negative trend in weaning mass at both populations, suggesting a rise in limiting factors that is hypothesized to relate to concurrent local population size increases. Weaning mass tended to be higher when sea surface temperatures were warmer (with a stronger positive effect at Gough Island) and during positive phases of the Southern Oscillation Index (La Niña events), with a stronger positive effect in males. Given the low weaning mass of Gough Island fur seal pups, continued population growth here seems unlikely. While density-dependent regulation appears to have increased in strength at Marion Island, terminating rapid population growth, current weaning weights remain above the physiological limits of growth in subantarctic fur seals.
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Affiliation(s)
- W. Chris Oosthuizen
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria , Private Bag X20, Hatfield 0028 , South Africa (WCO, PJNdB, MW, MNB)
| | - P. J. Nico de Bruyn
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria , Private Bag X20, Hatfield 0028 , South Africa (WCO, PJNdB, MW, MNB)
| | - Mia Wege
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria , Private Bag X20, Hatfield 0028 , South Africa (WCO, PJNdB, MW, MNB)
| | - Marthán N. Bester
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria , Private Bag X20, Hatfield 0028 , South Africa (WCO, PJNdB, MW, MNB)
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Haddad WA, Reisinger RR, Scott T, Bester MN, de Bruyn PJN. Multiple occurrences of king penguin (Aptenodytes patagonicus) sexual harassment by Antarctic fur seals (Arctocephalus gazella). Polar Biol 2014. [DOI: 10.1007/s00300-014-1618-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Wege M, Postma M, Tosh CA, de Bruyn PJN, Bester MN. First confirmed record of a leucistic Antarctic fur seal pup born outside the Scotia Arc Islands. Polar Biol 2014. [DOI: 10.1007/s00300-014-1573-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Bonin CA, Goebel ME, Forcada J, Burton RS, Hoffman JI. Unexpected genetic differentiation between recently recolonized populations of a long-lived and highly vagile marine mammal. Ecol Evol 2013; 3:3701-12. [PMID: 24198934 PMCID: PMC3810869 DOI: 10.1002/ece3.732] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 07/24/2013] [Indexed: 11/08/2022] Open
Abstract
Many species have been heavily exploited by man leading to local extirpations, yet few studies have attempted to unravel subsequent recolonization histories. This has led to a significant gap in our knowledge of the long-term effects of exploitation on the amount and structure of contemporary genetic variation, with important implications for conservation. The Antarctic fur seal provides an interesting case in point, having been virtually exterminated in the nineteenth century but subsequently staged a dramatic recovery to recolonize much of its original range. Consequently, we evaluated the hypothesis that South Georgia (SG), where a few million seals currently breed, was the main source of immigrants to other locations including Livingston Island (LI), by genotyping 366 individuals from these two populations at 17 microsatellite loci and sequencing a 263 bp fragment of the mitochondrial hypervariable region 1. Contrary to expectations, we found highly significant genetic differences at both types of marker, with 51% of LI individuals carrying haplotypes that were not observed in 246 animals from SG. Moreover, the youngest of three sequentially founded colonies at LI showed greater similarity to SG at mitochondrial DNA than microsatellites, implying temporal and sex-specific variation in recolonization. Our findings emphasize the importance of relict populations and provide insights into the mechanisms by which severely depleted populations can recover while maintaining surprisingly high levels of genetic diversity.
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Affiliation(s)
- Carolina A Bonin
- Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California San Diego 9500 Gilman Dr., La Jolla, California, 92093-0208
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Berry O, Spiller LC, Campbell R, Hitchen Y, Kennington WJ. Population recovery of the New Zealand fur seal in southern Australia: a molecular DNA analysis. J Mammal 2012. [DOI: 10.1644/11-mamm-a-206.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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de OLIVEIRA LR, LOIZAGA DE CASTRO R, CÁRDENAS-ALAYZA S, BONATTO SL. Conservation genetics of South American aquatic mammals: an overview of gene diversity, population structure, phylogeography, non-invasive methods and forensics. Mamm Rev 2011. [DOI: 10.1111/j.1365-2907.2011.00201.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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30
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Hoffman JI, Grant SM, Forcada J, Phillips CD. Bayesian inference of a historical bottleneck in a heavily exploited marine mammal. Mol Ecol 2011; 20:3989-4008. [PMID: 21895820 DOI: 10.1111/j.1365-294x.2011.05248.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Emerging Bayesian analytical approaches offer increasingly sophisticated means of reconstructing historical population dynamics from genetic data, but have been little applied to scenarios involving demographic bottlenecks. Consequently, we analysed a large mitochondrial and microsatellite dataset from the Antarctic fur seal Arctocephalus gazella, a species subjected to one of the most extreme examples of uncontrolled exploitation in history when it was reduced to the brink of extinction by the sealing industry during the late eighteenth and nineteenth centuries. Classical bottleneck tests, which exploit the fact that rare alleles are rapidly lost during demographic reduction, yielded ambiguous results. In contrast, a strong signal of recent demographic decline was detected using both Bayesian skyline plots and Approximate Bayesian Computation, the latter also allowing derivation of posterior parameter estimates that were remarkably consistent with historical observations. This was achieved using only contemporary samples, further emphasizing the potential of Bayesian approaches to address important problems in conservation and evolutionary biology.
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Affiliation(s)
- J I Hoffman
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany.
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Rivière-Dobigny T, Herbreteau V, Khamsavath K, Douangboupha B, Morand S, Michaux JR, Hugot JP. Preliminary assessment of the genetic population structure of the enigmatic speciesLaonastes aenigmamus(Rodentia: Diatomyidae). J Mammal 2011. [DOI: 10.1644/10-mamm-a-028.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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ANDERSEN LISELOTTEW, LYDERSEN CHRISTIAN, FRIE ANNEK, ROSING-ASVID AQQALU, HAUKSSON ERLINGUR, KOVACS KITM. A population on the edge: genetic diversity and population structure of the world's northernmost harbour seals (Phoca vitulina). Biol J Linn Soc Lond 2011. [DOI: 10.1111/j.1095-8312.2010.01577.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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AUTHIER M, CAM E, GUINET C. Selection for increased body length in Subantarctic fur seals on Amsterdam Island. J Evol Biol 2010; 24:607-16. [DOI: 10.1111/j.1420-9101.2010.02193.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Janosik AM, Halanych KM. Unrecognized Antarctic biodiversity: a case study of the genus Odontaster (Odontasteridae; Asteroidea). Integr Comp Biol 2010; 50:981-92. [PMID: 21558254 DOI: 10.1093/icb/icq119] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Antarctica has a complex and multifaceted geologic and oceanographic history that has influenced and shaped patterns of marine invertebrate diversity. This evolutionary history consists of major events on a wide range of time scales such as the formation of the Antarctic Polar Front (25-41 million years ago) to repeated glacial cycles during the past million years. These factors variably influenced genetic connectivity of fauna to produce a highly unique, but incredibly diverse marine community. Use of molecular phylogeographic methods is creating the need to revise our understanding of Antarctic patterns of biodiversity. In particular, almost every phylogeographic study carried out to date, suggests that the biodiversity of Antarctic marine shelf fauna is considerably underestimated. In discovering this diversity, some lineages (i.e., cryptic lineages) show no diagnostic morphological differences whereas others (i.e., unrecognized species) show differences that were unknown to science. The sea star genus Odontaster is among the best-studied of Antarctic invertebrate groups. Nonetheless, two unrecognized lineages were recently discovered along the Antarctic Peninsula, which is one of the best-studied regions in Antarctica. Herein, we elucidate the molecular and morphological uniqueness of these species and name them O. roseus and O. pearsei. The latter is in honor of John Pearse, an Antarctic biologist, as well as past President and long-time member of the Society of Integrative and Comparative Biology.
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Affiliation(s)
- Alexis M Janosik
- Department of Biological Sciences, Auburn University, 101 Rouse Life Sciences Building, Auburn, AL 36849, USA.
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Túnez JI, Cappozzo HL, Nardelli M, Cassini MH. Population genetic structure and historical population dynamics of the South American sea lion, Otaria flavescens, in north-central Patagonia. Genetica 2010; 138:831-41. [DOI: 10.1007/s10709-010-9466-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 05/24/2010] [Indexed: 11/25/2022]
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Dickerson BR, Ream RR, Vignieri SN, Bentzen P. Population structure as revealed by mtDNA and microsatellites in northern fur seals, Callorhinus ursinus, throughout their range. PLoS One 2010; 5:e10671. [PMID: 20498854 PMCID: PMC2871788 DOI: 10.1371/journal.pone.0010671] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 04/07/2010] [Indexed: 11/20/2022] Open
Abstract
Background The northern fur seal (Callorhinus ursinus; NFS) is a widely distributed pinniped that has been shown to exhibit a high degree of philopatry to islands, breeding areas on an island, and even to specific segments of breeding areas. This level of philopatry could conceivably lead to highly genetically divergent populations. However, northern fur seals have the potential for dispersal across large distances and have experienced repeated rapid population expansions following glacial retreat and the more recent cessation of intensive harvest pressure. Methodology/Principal Findings Using microsatellite and mitochondrial loci, we examined population structure in NFS throughout their range. We found only weak population genetic structure among breeding islands including significant FST and ΦST values between eastern and western Pacific islands. Conclusions We conclude that insufficient time since rapid population expansion events (both post glacial and following the cessation of intense harvest pressure) mixed with low levels of contemporary migration have resulted in an absence of genetic structure across the entire northern fur seal range.
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Affiliation(s)
- Bobette R Dickerson
- National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, Seattle, Washington, United States of America.
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Lancaster ML, Goldsworthy SD, Sunnucks P. Two behavioural traits promote fine-scale species segregation and moderate hybridisation in a recovering sympatric fur seal population. BMC Evol Biol 2010; 10:143. [PMID: 20470387 PMCID: PMC2885394 DOI: 10.1186/1471-2148-10-143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 05/14/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In systems where two or more species experience secondary contact, behavioural factors that regulate interspecific gene flow may be important for maintaining species boundaries and reducing the incidence of hybridisation. At subantarctic Macquarie Island, two species of fur seal breed in close proximity to one another, hybridise at very high levels (up to 21% of hybrid pups are born annually), yet retain discrete gene pools. Using spatial and genetic information collected for pups and adults over twelve years, we assessed two behavioural traits - inter-annual site fidelity and differences in habitat use between the species - as possible contributors to the maintenance of this species segregation. Further, we explored the breakdown of these traits in pure-species individuals and hybrids. RESULTS We found virtually complete spatial segregation of the parental species, with only one exception; a single territory that contained adults of both species and also the highest concentration of hybrid pups. The spatial distribution of each species was closely linked to habitat type (pebbled vs boulder beaches), with members of each species breeding almost exclusively on one type or the other but hybrids breeding on both or at the junction between habitats. Inter-annual site fidelity was high for both sexes of pure-species adults, with 66% of females and all males returning to the same territory or a neighbouring one in different years. An important consequence for pure females of breeding on the 'wrong' habitat type, and thus in a heterospecific aggregation, was the production of hybrid pups. Low habitat fidelity of hybrid females facilitated bi-directional backcrossing, resulting in more diverse hybrid offspring. CONCLUSION In a disturbed system where two sympatric fur seal species breed in close proximity, discrete gene pools are retained by extremely fine-scale and strong spatial segregation of the species. Two behavioural traits were found to be important in maintaining this stable population structure, and habitat type was a strong indicator of where species locate and a potentially powerful predictor of future directions of hybridisation. A direct consequence of the breakdown of this trait was the production of hybrid offspring, which may have severe implications if hybrids have reduced fitness.
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Affiliation(s)
- Melanie L Lancaster
- Zoology Department, La Trobe University, Bundoora, Victoria 3083, Australia.
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Hofmeyr GG, Amir OA. Vagrant Subantarctic Fur Seal on the Coast of Tanzania. AFRICAN ZOOLOGY 2010. [DOI: 10.3377/004.045.0112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Shaughnessy PD, McKenzie J, Lancaster ML, Goldsworthy SD, Dennis TE. Australian fur seals establish haulout sites and a breeding colony in South Australia. AUST J ZOOL 2010. [DOI: 10.1071/zo10017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Australian fur seals (Arctocephalus pusillus doriferus) breed on Bass Strait islands in Victoria and Tasmania. They have been recorded in South Australia (SA) for many years as non-breeding visitors and on Kangaroo Island frequently since 1988, mostly in breeding colonies of the New Zealand fur seal (A. forsteri) which is the most numerous pinniped in SA. Australian fur seals have displaced New Zealand fur seals from sections of the Cape Gantheaume colony on Kangaroo Island. North Casuarina Island produced 29 Australian fur seal pups in February 2008. Australian fur seal pups were larger than New Zealand fur seal pups in the same colony and have been identified genetically using a 263-bp fragment of the mitochondrial DNA control region. North Casuarina Island has been an important breeding colony of New Zealand fur seals, but pup numbers there decreased since 1992–93 (contrary to trends in SA for New Zealand fur seals), while numbers of Australian fur seals there have increased. This study confirms that Australian fur seals breed in SA. The two fur seal species compete for space onshore at several sites. Australian fur seals may compete for food with endangered Australian sea lions (Neophoca cinerea) because both are bottom feeders.
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Lancaster ML, Arnould JPY, Kirkwood R. Genetic status of an endemic marine mammal, the Australian fur seal, following historical harvesting. Anim Conserv 2009. [DOI: 10.1111/j.1469-1795.2009.00325.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Long-term variability in the abundance of Antarctic fur seals Arctocephalus gazella at Signy Island, South Orkneys. Polar Biol 2009. [DOI: 10.1007/s00300-009-0706-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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HOFFMAN JI, DASMAHAPATRA KK, AMOS W, PHILLIPS CD, GELATT TS, BICKHAM JW. Contrasting patterns of genetic diversity at three different genetic markers in a marine mammal metapopulation. Mol Ecol 2009; 18:2961-78. [DOI: 10.1111/j.1365-294x.2009.04246.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Fur seals at Macquarie Island: post-sealing colonisation, trends in abundance and hybridisation of three species. Polar Biol 2009. [DOI: 10.1007/s00300-009-0645-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Rogers AD. Evolution and biodiversity of Antarctic organisms: a molecular perspective. Philos Trans R Soc Lond B Biol Sci 2008; 362:2191-214. [PMID: 17553774 PMCID: PMC2443175 DOI: 10.1098/rstb.2006.1948] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Antarctic biota is highly endemic, and the diversity and abundance of taxonomic groups differ from elsewhere in the world. Such characteristics have resulted from evolution in isolation in an increasingly extreme environment over the last 100 Myr. Studies on Antarctic species represent some of the best examples of natural selection at the molecular, structural and physiological levels. Analyses of molecular genetics data are consistent with the diversity and distribution of marine and terrestrial taxa having been strongly influenced by geological and climatic cooling events over the last 70 Myr. Such events have resulted in vicariance driven by continental drift and thermal isolation of the Antarctic, and in pulses of species range contraction into refugia and subsequent expansion and secondary contact of genetically distinct populations or sister species during cycles of glaciation. Limited habitat availability has played a major role in structuring populations of species both in the past and in the present day. For these reasons, despite the apparent simplicity or homogeneity of Antarctic terrestrial and marine environments, populations of species are often geographically structured into genetically distinct lineages. In some cases, genetic studies have revealed that species defined by morphological characters are complexes of cryptic or sibling species. Climate change will cause changes in the distribution of many Antarctic and sub-Antarctic species through affecting population-level processes such as life history and dispersal.
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LANCASTER MELANIEL, GOLDSWORTHY SIMOND, SUNNUCKS PAUL. Multiple mating strategies explain unexpected genetic mixing of New Zealand fur seals with two congenerics in a recently recolonized population. Mol Ecol 2007; 16:5267-76. [DOI: 10.1111/j.1365-294x.2007.03586.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bester MN, de Clercq H, Hofmeyr GJG, de Bruyn PJN. Leucistic southern elephant seal at Marion Island? Polar Biol 2007. [DOI: 10.1007/s00300-007-0380-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Multiple origins of vagrant Subantarctic fur seals: a long journey to the Brazilian coast detected by molecular markers. Polar Biol 2007. [DOI: 10.1007/s00300-007-0358-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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