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Atkinson SN, Laidre KL, Arnold TW, Stapleton S, Regehr EV, Born EW, Wiig Ø, Dyck M, Lunn NJ, Stern HL, Paetkau D. A novel mark-recapture-recovery survey using genetic sampling for polar bears Ursus maritimus in Baffin Bay. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Changes in sea-ice dynamics are affecting polar bears Ursus maritimus across their circumpolar range, which highlights the importance of periodic demographic assessments to inform management and conservation. We used genetic mark-recapture-recovery to derive estimates of abundance and survival for the Baffin Bay (BB) polar bear subpopulation—the first time this method has been used successfully for this species. Genetic data from tissue samples we collected via biopsy darting were combined with historical physical capture and harvest recovery data. The combined data set consisted of 1410 genetic samples (2011-2013), 914 physical captures (1993-1995, 1997), and 234 harvest returns of marked bears (1993-2013). The estimate of mean subpopulation abundance was 2826 (95% CI = 2284-3367) in 2012-2013. Estimates of annual survival (mean ± SE) were 0.90 ± 0.05 and 0.78 ± 0.06 for females and males age ≥2 yr, respectively. The proportion of total mortality of adult females and males that was attributed to legal harvest was 0.16 ± 0.05 and 0.26 ± 0.06, respectively. Remote sensing sea-ice data, telemetry data, and spatial distribution of onshore sampling indicated that polar bears were more likely to use offshore sea-ice habitat during the 1990s sampling period compared to the 2010s. Furthermore, in the 1990s, sampling of deep fjords and inland areas was limited, and no offshore sampling occurred in either time period, which precluded comparisons of abundance between the 1993-1997 and 2011-2013 study periods. Our findings demonstrate that genetic sampling can be a practical method for demographic assessment of polar bears over large spatial and temporal scales.
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Affiliation(s)
- SN Atkinson
- Wildlife Research Section, Department of Environment, Government of Nunavut, Igloolik, NU X0A 0L0, Canada
| | - KL Laidre
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - TW Arnold
- Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - S Stapleton
- Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - EV Regehr
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - EW Born
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Ø Wiig
- Natural History Museum, University of Oslo, 0318, Oslo, Norway
| | - M Dyck
- Wildlife Research Section, Department of Environment, Government of Nunavut, Igloolik, NU X0A 0L0, Canada
| | - NJ Lunn
- Environment and Climate Change Canada, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - HL Stern
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - D Paetkau
- Wildlife Genetics International, Nelson, BC V1L 5P9, Canada
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Lindsay JM, Laidre KL, Conn PB, Moreland EE, Boveng PL. Modeling ringed seal Pusa hispida habitat and lair emergence timing in the eastern Bering and Chukchi Seas. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ringed seals Pusa hispida are reliant on snow and sea ice for denning, and a better understanding of ringed seal habitat selection and timing of emergence from snow dens (also called lairs) is needed to quantify and predict effects of climate change in the Arctic. We used generalized additive models to assess relationships between ringed seal counts, from spring aerial surveys in the Bering Sea (2012 and 2013) and Chukchi Sea (2016), and spatiotemporal covariates including survey date, remotely sensed snow and sea-ice values, and short-term weather data. We produced separate models for total ringed seal counts and for pup counts within each region. Our models showed that in both areas, total ringed seal counts increased over the course of the spring, especially after 15 May, indicating emergence from lairs and/or the onset of basking behavior. For the more northerly Chukchi Sea, we found a substantial unimodal effect of snow melt progression and a positive effect of snow depth on total ringed seal counts. In contrast, Bering Sea total ringed seal counts and pup counts in both regions were affected much more strongly by date than by habitat variables. Overall, our findings demonstrate that snow depth and melt play an important role in the timing of ringed seal den emergence, particularly in the Chukchi Sea, and suggest that ringed seal denning may be affected by continued shifts in melt and snow depth associated with climate change.
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Affiliation(s)
- JM Lindsay
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98105, USA
| | - KL Laidre
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98105, USA
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - PB Conn
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98115, USA
| | - EE Moreland
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98115, USA
| | - PL Boveng
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98115, USA
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Nelms SE, Alfaro-Shigueto J, Arnould JPY, Avila IC, Bengtson Nash S, Campbell E, Carter MID, Collins T, Currey RJC, Domit C, Franco-Trecu V, Fuentes MMPB, Gilman E, Harcourt RG, Hines EM, Hoelzel AR, Hooker SK, Johnston DW, Kelkar N, Kiszka JJ, Laidre KL, Mangel JC, Marsh H, Maxwell SM, Onoufriou AB, Palacios DM, Pierce GJ, Ponnampalam LS, Porter LJ, Russell DJF, Stockin KA, Sutaria D, Wambiji N, Weir CR, Wilson B, Godley BJ. Marine mammal conservation: over the horizon. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01115] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Marine mammals can play important ecological roles in aquatic ecosystems, and their presence can be key to community structure and function. Consequently, marine mammals are often considered indicators of ecosystem health and flagship species. Yet, historical population declines caused by exploitation, and additional current threats, such as climate change, fisheries bycatch, pollution and maritime development, continue to impact many marine mammal species, and at least 25% are classified as threatened (Critically Endangered, Endangered or Vulnerable) on the IUCN Red List. Conversely, some species have experienced population increases/recoveries in recent decades, reflecting management interventions, and are heralded as conservation successes. To continue these successes and reverse the downward trajectories of at-risk species, it is necessary to evaluate the threats faced by marine mammals and the conservation mechanisms available to address them. Additionally, there is a need to identify evidence-based priorities of both research and conservation needs across a range of settings and taxa. To that effect we: (1) outline the key threats to marine mammals and their impacts, identify the associated knowledge gaps and recommend actions needed; (2) discuss the merits and downfalls of established and emerging conservation mechanisms; (3) outline the application of research and monitoring techniques; and (4) highlight particular taxa/populations that are in urgent need of focus.
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Affiliation(s)
- SE Nelms
- Centre for Ecology and Conservation, University of Exeter, Cornwall, TR10 9EZ, UK
| | - J Alfaro-Shigueto
- ProDelphinus, Jose Galvez 780e, Miraflores, Perú
- Facultad de Biologia Marina, Universidad Cientifica del Sur, Lima, Perú
| | - JPY Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - IC Avila
- Grupo de Ecología Animal, Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad del Valle, Cali, Colombia
| | - S Bengtson Nash
- Environmental Futures Research Institute (EFRI), Griffith University, Nathan Campus, 170 Kessels Road, Nathan, QLD 4111, Australia
| | - E Campbell
- Centre for Ecology and Conservation, University of Exeter, Cornwall, TR10 9EZ, UK
- ProDelphinus, Jose Galvez 780e, Miraflores, Perú
| | - MID Carter
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife, KY16 8LB, UK
| | - T Collins
- Wildlife Conservation Society, 2300 Southern Blvd., Bronx, NY 10460, USA
| | - RJC Currey
- Marine Stewardship Council, 1 Snow Hill, London, EC1A 2DH, UK
| | - C Domit
- Laboratory of Ecology and Conservation, Marine Study Center, Universidade Federal do Paraná, Brazil
| | - V Franco-Trecu
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Uruguay
| | - MMPB Fuentes
- Marine Turtle Research, Ecology and Conservation Group, Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - E Gilman
- Pelagic Ecosystems Research Group, Honolulu, HI 96822, USA
| | - RG Harcourt
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - EM Hines
- Estuary & Ocean Science Center, San Francisco State University, 3150 Paradise Dr. Tiburon, CA 94920, USA
| | - AR Hoelzel
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - SK Hooker
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife, KY16 8LB, UK
| | - DW Johnston
- Duke Marine Lab, 135 Duke Marine Lab Road, Beaufort, NC 28516, USA
| | - N Kelkar
- Ashoka Trust for Research in Ecology and the Environment (ATREE), Royal Enclave, Srirampura, Jakkur PO, Bangalore 560064, Karnataka, India
| | - JJ Kiszka
- Department of Biological Sciences, Coastlines and Oceans Division, Institute of Environment, Florida International University, Miami, FL 33199, USA
| | - KL Laidre
- Polar Science Center, APL, University of Washington, 1013 NE 40th Street, Seattle, WA 98105, USA
| | - JC Mangel
- Centre for Ecology and Conservation, University of Exeter, Cornwall, TR10 9EZ, UK
- ProDelphinus, Jose Galvez 780e, Miraflores, Perú
| | - H Marsh
- James Cook University, Townsville, QLD 48111, Australia
| | - SM Maxwell
- School of Interdisciplinary Arts and Sciences, University of Washington Bothell, Bothell WA 98011, USA
| | - AB Onoufriou
- School of Biology, University of St Andrews, Fife, KY16 8LB, UK
- Universidad de La Laguna, San Cristóbal de La Laguna, Spain
| | - DM Palacios
- Marine Mammal Institute, Hatfield Marine Science Center, Oregon State University, Newport, OR, 97365, USA
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97330, USA
| | - GJ Pierce
- Centre for Ecology and Conservation, University of Exeter, Cornwall, TR10 9EZ, UK
- Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Cientificas, Eduardo Cabello 6, 36208 Vigo, Pontevedra, Spain
| | - LS Ponnampalam
- The MareCet Research Organization, 40460 Shah Alam, Malaysia
| | - LJ Porter
- SMRU Hong Kong, University of St. Andrews, Hong Kong
| | - DJF Russell
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife, KY16 8LB, UK
- Centre for Research into Ecological and Environmental Modelling, University of St Andrews, St Andrews, Fife, KY16 8LB, UK
| | - KA Stockin
- Animal Welfare Science and Bioethics Centre, School of Veterinary Science, Massey University, Private Bag 11-222, Palmerston North, New Zealand
| | - D Sutaria
- School of Interdisciplinary Arts and Sciences, University of Washington Bothell, Bothell WA 98011, USA
| | - N Wambiji
- Kenya Marine and Fisheries Research Institute, P.O. Box 81651, Mombasa-80100, Kenya
| | - CR Weir
- Ketos Ecology, 4 Compton Road, Kingsbridge, Devon, TQ7 2BP, UK
| | - B Wilson
- Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK
| | - BJ Godley
- Centre for Ecology and Conservation, University of Exeter, Cornwall, TR10 9EZ, UK
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Chambault P, Tervo OM, Garde E, Hansen RG, Blackwell SB, Williams TM, Dietz R, Albertsen CM, Laidre KL, Nielsen NH, Richard P, Sinding MHS, Schmidt HC, Heide-Jørgensen MP. The impact of rising sea temperatures on an Arctic top predator, the narwhal. Sci Rep 2020; 10:18678. [PMID: 33122802 PMCID: PMC7596713 DOI: 10.1038/s41598-020-75658-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 10/14/2020] [Indexed: 02/04/2023] Open
Abstract
Arctic top predators are expected to be impacted by increasing temperatures associated with climate change, but the relationship between increasing sea temperatures and population dynamics of Arctic cetaceans remains largely unexplored. Narwhals (Monodon monoceros) are considered to be among the most sensitive of Arctic endemic marine mammals to climate change due to their limited prey selection, strict migratory patterns and high site fidelity. In the context of climate change, we assume that the population dynamics of narwhals are partly influenced by changes in environmental conditions, with warm areas of increasing sea temperatures having lower abundance of narwhals. Using a unique large dataset of 144 satellite tracked narwhals, sea surface temperature (SST) data spanning 25 years (1993–2018) and narwhal abundance estimates from 17 localities, we (1) assessed the thermal exposure of this species, (2) investigated the SST trends at the summer foraging grounds, and (3) assessed the relationship between SST and abundance of narwhals. We showed a sharp SST increase in Northwest, Mideast and Southeast Greenland, whereas no change could be detected in the Canadian Arctic Archipelago (CAA) and in the Greenland Sea. The rising sea temperatures were correlated with the smallest narwhal abundance observed in the Mideast and Southeast Greenland (< 2000 individuals), where the mean summer sea temperatures were the highest (6.3 °C) compared to the cold waters of the CAA (0.7 °C) that were associated with the largest narwhal populations (> 40,000 individuals). These results support the hypothesis that warming ocean waters will restrict the habitat range of the narwhal, further suggesting that narwhals from Mideast and Southeast Greenland may be under pressure to abandon their traditional habitats due to ocean warming, and consequently either migrate further North or locally go extinct.
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Affiliation(s)
- P Chambault
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark.
| | - O M Tervo
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
| | - E Garde
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
| | - R G Hansen
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
| | - S B Blackwell
- Greeneridge Sciences, Inc, 5266 Hollister Avenue, Suite 107, Santa Barbara, CA, 93111, USA
| | | | - R Dietz
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - C M Albertsen
- DTU Aqua, Technical University of Denmark, 2800, Kgs. Lyngby, DK, Denmark
| | - K L Laidre
- Applied Physics Laboratory, Polar Science Center, University of Washington, Seattle, WA, 98105-6698, USA
| | - N H Nielsen
- Greenland Institute of Natural Resources, Box 570, 3900, Nuuk, Greenland
| | - P Richard
- Fisheries and Oceans Canada, Winnipeg, MB, R3T 2N6, Canada
| | - M H S Sinding
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark.,Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - H C Schmidt
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
| | - M P Heide-Jørgensen
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
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Laidre KL, Stern H, Born EW, Heagerty P, Atkinson S, Wiig Ø, Lunn NJ, Regehr EV, McGovern R, Dyck M. Changes in winter and spring resource selection by polar bears Ursus maritimus in Baffin Bay over two decades of sea-ice loss. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00886] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Kutschera VE, Frosch C, Janke A, Skírnisson K, Bidon T, Lecomte N, Fain SR, Eiken HG, Hagen SB, Arnason U, Laidre KL, Nowak C, Hailer F. High genetic variability of vagrant polar bears illustrates importance of population connectivity in fragmented sea ice habitats. Anim Conserv 2016. [DOI: 10.1111/acv.12250] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- V. E. Kutschera
- Senckenberg Biodiversity and Climate Research Centre (BiK-F); Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main; Germany
- Department of Evolutionary Biology, Evolutionary Biology Centre; Uppsala University; Uppsala Sweden
| | - C. Frosch
- Conservation Genetics Group; Senckenberg Research Institute and Natural History Museum Frankfurt; Gelnhausen Germany
| | - A. Janke
- Senckenberg Biodiversity and Climate Research Centre (BiK-F); Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main; Germany
- Institute for Ecology, Evolution and Diversity; Goethe University Frankfurt, Frankfurt am Main; Germany
| | - K. Skírnisson
- Institute for Experimental Pathology; Keldur, University of Iceland; Reykjavík Iceland
| | - T. Bidon
- Senckenberg Biodiversity and Climate Research Centre (BiK-F); Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main; Germany
| | - N. Lecomte
- Canada Research Chair in Polar and Boreal Ecology, Department of Biology; University of Moncton; Moncton NB Canada
- Government of Nunavut; Igloolik NU Canada
| | - S. R. Fain
- National Fish and Wildlife Forensic Laboratory; Ashland OR USA
| | - H. G. Eiken
- NIBIO, Norwegian Institute for Bioeconomy Research; Svanvik Norway
| | - S. B. Hagen
- NIBIO, Norwegian Institute for Bioeconomy Research; Svanvik Norway
| | - U. Arnason
- Faculty of Medicine; University of Lund; Lund Sweden
| | - K. L. Laidre
- Applied Physics Laboratory; Polar Science Center, University of Washington; Seattle WA USA
| | - C. Nowak
- Conservation Genetics Group; Senckenberg Research Institute and Natural History Museum Frankfurt; Gelnhausen Germany
| | - F. Hailer
- Senckenberg Biodiversity and Climate Research Centre (BiK-F); Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main; Germany
- School of Biosciences; Cardiff University; Cardiff, Wales UK
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Born EW, Stefansson E, Mikkelsen B, Laidre KL, Andersen LW, Rigét FF, Villum Jensen M, Bloch D. A note on a walrus’ European odyssey. NAMMCOSP 2014. [DOI: 10.7557/3.2921] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study reports on the first successful identification of the site of origin of an extralimital walrus in Europe. On 24 February 2010 an adult male Atlantic walrus (Odobenus rosmarus rosmarus) migrant was instrumented with a SPOT-5 satellite-linked transmitter (SLT) while hauled out on a beach on the Faroe Islands at 62° 15' N/06° 32' W. This SLT transmitted until 5 March during which period the walrus made local movements, likely for feeding. Transmissions were not received during 6-25 March, however, visual observations during this time indicated that the walrus remained at the Faroe Islands. A second transmitter was deployed on the same animal on 25 March 2010 at another site on the islands (62° 16' N/07° 04' W). Activity data collected over 13 days indicated that the walrus hauled out in three different places in the Faroe Islands and used a total of 24% of its time resting on land. On 29 March 2010 the walrus left the Faroe Islands and headed WNW towards NE Iceland. On 2 April it took a NNE course and swam towards Svalbard where the last location was received from a sea ice covered area on 25 April 2010 at 78° 27' N/09° 20' E (i.e. ca. 40 km west of the island of Prins Karls Forland in the western Svalbard archipelago). During 29 March-22 April the walrus swam a minimum distance of 2216 km between the last location at the Faroe Islands and the first location at Svalbard, with an average swimming speed of 4.5 km/h. A genetic analysis indicated that this walrus belonged to the Svalbard-Franz Josef Land subpopulation, thereby confirming that it returned to its site of origin.
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Palacios DM, Baumgartner MF, Laidre KL, Gregr EJ. Beyond correlation: integrating environmentally and behaviourally mediated processes in models of marine mammal distributions. ENDANGER SPECIES RES 2013. [DOI: 10.3354/esr00558] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Gregr EJ, Baumgartner MF, Laidre KL, Palacios DM. Marine mammal habitat models come of age: the emergence of ecological and management relevance. ENDANGER SPECIES RES 2013. [DOI: 10.3354/esr00476] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Affiliation(s)
| | - P. R. Richard
- Department of Fisheries and Oceans; 501 University Crescent; Winnipeg; MB; Canada
| | - R. Dietz
- Department of Bioscience; Arctic Research Centre; Aarhus University; Roskilde; Denmark
| | - K. L. Laidre
- Polar Science Center; Applied Physics Laboratory; University of Washington; Seattle; WA; USA
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Wiig Ø, Heide-Jørgensen MP, Lindqvist C, Laidre KL, Postma LD, Dueck L, Palsbøll PJ, Bachmann L. Recaptures of genotyped bowhead whales Balaena mysticetus in eastern Canada and West Greenland. ENDANGER SPECIES RES 2011. [DOI: 10.3354/esr00365] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Heide-Jørgensen MP, Laidre KL, Wiig Ø, Postma L, Dueck L, Bachmann L. Large-scale sexual segregation of bowhead whales. ENDANGER SPECIES RES 2010. [DOI: 10.3354/esr00315] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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13
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Affiliation(s)
- K. L. Laidre
- Polar Science Center, Applied Physics Laboratory University of Washington Seattle Washington USA
- Greenland Institute of Natural Resources Nuuk Greenland
| | | | - W. Ermold
- Polar Science Center, Applied Physics Laboratory University of Washington Seattle Washington USA
| | - M. Steele
- Polar Science Center, Applied Physics Laboratory University of Washington Seattle Washington USA
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Heide-JØrgensen MP, Laidre KL, Burt ML, Borchers DL, Marques TA, Hansen RG, Rasmussen M, Fossette S. Abundance of narwhals (Monodon monoceros) on the hunting grounds in Greenland. J Mammal 2010. [DOI: 10.1644/09-mamm-a-198.1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Laidre KL, Estes JA, Tinker MT, Bodkin J, Monson D, Schneider K. Patterns of growth and body condition in sea otters from the Aleutian archipelago before and after the recent population decline. J Anim Ecol 2006; 75:978-89. [PMID: 17009761 DOI: 10.1111/j.1365-2656.2006.01117.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Growth models for body mass and length were fitted to data collected from 1842 sea otters Enhydra lutris shot or live-captured throughout south-west Alaska between 1967 and 2004. Growth curves were constructed for each of two main year groups: 1967-71 when the population was at or near carrying capacity and 1992-97 when the population was in steep decline. Analyses of data collected from animals caught during 2004, when the population density was very low, were precluded by a small sample size and consequently only examined incidentally to the main growth curves. 2. Growth curves demonstrated a significant increase in body mass and body length at age in the 1990s. Asymptotic values of body mass were 12-18% higher in the 1990s than in the 1960s/70s, and asymptotic values for body length were 10-11% higher between the same periods. Data collected in 2004 suggest a continued increase in body size, with nearly all data points for mass and length falling significantly above the 1990s growth curves. 3. In addition to larger asymptotic values for mass and length, the rate of growth towards asymptotic values was more rapid in the 1990s than in the 1960s/70s: sea otters reached 95% of asymptotic body mass and body length 1-2 years earlier in the 1990s. 4. Body condition (as measured by the log mass/log length ratio) was significantly greater in males than in females. There was also an increasing trend from the 1960s/70s through 2004 despite much year-to-year variation. 5. Population age structures differed significantly between the 1960s/70s and the 1990s with the latter distribution skewed toward younger age classes (indicating an altered lx function) suggesting almost complete relaxation of age-dependent mortality patterns (i.e. those typical of food-limited populations). 6. This study spanned a period of time over which the population status of sea otters in the Aleutian archipelago declined precipitously from levels at or near equilibrium densities at some islands in the 1960s/70s to < 5% of estimated carrying capacity by the late 1990s. The results of this study indicate an improved overall health of sea otters over the period of decline and suggest that limited nutritional resources were not the cause of the observed reduced population abundance. Our findings are consistent with the hypothesis that the decline was caused by increased killer whale predation.
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Affiliation(s)
- K L Laidre
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California, Santa Cruz, CA 95060, USA.
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Heide-Jørgensen MP, Richard P, Dietz R, Laidre KL, Orr J, Schmidt HC. An estimate of the fraction of belugas (Delphinapterus leucas) in the Canadian high Arctic that winter in West Greenland. Polar Biol 2003. [DOI: 10.1007/s00300-003-0488-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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