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367 results on '"Harcourt, Robert G."'

1. A continuous-time state-space model for rapid quality-control of Argos locations from animal-borne tags

Author

Jonsen, Ian D., Patterson, Toby A., Costa, Daniel P., Doherty, Philip D., Godley, Brendan J., Grecian, W. James, Guinet, Christophe, Hoenner, Xavier, Kienle, Sarah S., Robison, Patrick W., Votier, Stephen C., Witt, Matthew J., Hindell, Mark A., Harcourt, Robert G., and McMahon, Clive R.

Subjects
Quantitative Biology - Quantitative Methods, Statistics - Applications
Abstract

State-space models are important tools for quality control of error-prone animal movement data. The near real-time (within 24 h) capability of the Argos satellite system aids dynamic ocean management of human activities by informing when animals enter intensive use zones. This capability also facilitates use of ocean observations from animal-borne sensors in operational ocean forecasting models. Such near real-time data provision requires rapid, reliable quality control to deal with error-prone Argos locations. We formulate a continuous-time state-space model for the three types of Argos location data (Least-Squares, Kalman filter, and Kalman smoother), accounting for irregular timing of observations. Our model is deliberately simple to ensure speed and reliability for automated, near real-time quality control of Argos data. We validate the model by fitting to Argos data collected from 61 individuals across 7 marine vertebrates and compare model-estimated locations to GPS locations. Estimation accuracy varied among species with median Root Mean Squared Errors usually < 5 km and decreased with increasing data sampling rate and precision of Argos locations. Including a model parameter to inflate Argos error ellipse sizes resulted in more accurate location estimates. In some cases, the model appreciably improved the accuracy of the Argos Kalman smoother locations, which should not be possible if the smoother uses all available information. Our model provides quality-controlled locations from Argos Least-Squares or Kalman filter data with slightly better accuracy than Argos Kalman smoother data that are only available via reprocessing. Simplicity and ease of use make the model suitable both for automated quality control of near real-time Argos data and for manual use by researchers working with historical Argos data., Comment: 25 pages, 10 figures

Published
2020
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3. Big data analyses reveal patterns and drivers of the movements of southern elephant seals

Author

Rodríguez, Jorge P., Fernández-Gracia, Juan, Thums, Michele, Hindell, Mark A., Sequeira, Ana M. M., Meekan, Mark G., Costa, Daniel P., Guinet, Christophe, Harcourt, Robert G., McMahon, Clive R., Muelbert, Monica, Duarte, Carlos M., and Eguíluz, Víctor M.

Subjects
Quantitative Biology - Quantitative Methods, Physics - Biological Physics, Physics - Data Analysis, Statistics and Probability, Quantitative Biology - Populations and Evolution
Abstract

The growing number of large databases of animal tracking provides an opportunity for analyses of movement patterns at the scales of populations and even species. We used analytical approaches, developed to cope with big data, that require no a priori assumptions about the behaviour of the target agents, to analyse a pooled tracking dataset of 272 elephant seals (Mirounga leonina) in the Southern Ocean, that was comprised of >500,000 location estimates collected over more than a decade. Our analyses showed that the displacements of these seals were described by a truncated power law distribution across several spatial and temporal scales, with a clear signature of directed movement. This pattern was evident when analysing the aggregated tracks despite a wide diversity of individual trajectories. We also identified marine provinces that described the migratory and foraging habitats of these seals. Our analysis provides evidence for the presence of intrinsic drivers of movement, such as memory, that cannot be detected using common models of movement behaviour. These results highlight the potential for big data techniques to provide new insights into movement behaviour when applied to large datasets of animal tracking., Comment: 18 pages, 5 figures, 6 supplementary figures

Published
2018
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6. Long‐term effects of tagging fishes with electronic tracking devices.

Author

Matley, Jordan K., Klinard, Natalie V., Jaine, Fabrice R. A., Lennox, Robert J., Koopman, Natalie, Reubens, Jan T., Harcourt, Robert G., Cooke, Steven J., and Huveneers, Charlie

Subjects
ANIMAL radio tracking, FISH tagging, RADIO telemetry, SATELLITE telemetry, FISH conservation
Abstract

Tagging fishes with internal or external electronic tracking devices (acoustic, radio, satellite, or archival tags) is invaluable to behavioural, ecological, and welfare research, but may have adverse effects on the animals studied. While short‐term responses to tagging (e.g., days to weeks) have often been investigated, less information is available on longer‐term impacts (e.g., months to years) and the potential chronic effects of tagging on basic biological needs such as foraging and reproduction. Here, we synthesize existing knowledge from peer‐reviewed acoustic, radio, satellite, and archival tagging articles (n = 149) and anecdotal accounts (n = 72) from 36 researchers to assess the effects of tagging over prolonged periods. We identified a dearth of research that has specifically measured or quantified the impacts of tagging over a period longer than a few weeks or months (e.g., median experimental study duration = 33 days; n = 120 articles). Nevertheless, there was limited evidence to support a net negative long‐term impact from the implantation or attachment of electronic devices. Considerations and future research directions are discussed with the goal of generating guidance to the research community and minimizing potentially detrimental impacts to study animals. Given the global application and relevance of electronic tagging research to inform conservation and management of fishes, it is imperative for scientists to continue evaluating how tagging procedures affect animal welfare, fate, and the interpretation of tracking data. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Big data analyses reveal patterns and drivers of the movements of southern elephant seals.

Author

Rodríguez, Jorge P, Fernández-Gracia, Juan, Thums, Michele, Hindell, Mark A, Sequeira, Ana MM, Meekan, Mark G, Costa, Daniel P, Guinet, Christophe, Harcourt, Robert G, McMahon, Clive R, Muelbert, Monica, Duarte, Carlos M, and Eguíluz, Víctor M

Subjects
Animals, Seals, Earless, Animal Migration, Feeding Behavior, Ecosystem, Locomotion, Data Mining, Spatial Analysis, Seals, Earless, Biochemistry and Cell Biology, Other Physical Sciences
Abstract

The growing number of large databases of animal tracking provides an opportunity for analyses of movement patterns at the scales of populations and even species. We used analytical approaches, developed to cope with "big data", that require no 'a priori' assumptions about the behaviour of the target agents, to analyse a pooled tracking dataset of 272 elephant seals (Mirounga leonina) in the Southern Ocean, that was comprised of >500,000 location estimates collected over more than a decade. Our analyses showed that the displacements of these seals were described by a truncated power law distribution across several spatial and temporal scales, with a clear signature of directed movement. This pattern was evident when analysing the aggregated tracks despite a wide diversity of individual trajectories. We also identified marine provinces that described the migratory and foraging habitats of these seals. Our analysis provides evidence for the presence of intrinsic drivers of movement, such as memory, that cannot be detected using common models of movement behaviour. These results highlight the potential for "big data" techniques to provide new insights into movement behaviour when applied to large datasets of animal tracking.

Published
2017

8. Circumpolar habitat use in the southern elephant seal: implications for foraging success and population trajectories

Author

Hindell, Mark A, McMahon, Clive R, Bester, Marthán N, Boehme, Lars, Costa, Daniel, Fedak, Mike A, Guinet, Christophe, Herraiz‐Borreguero, Laura, Harcourt, Robert G, Huckstadt, Luis, Kovacs, Kit M, Lydersen, Christian, McIntyre, Trevor, Muelbert, Monica, Patterson, Toby, Roquet, Fabien, Williams, Guy, and Charrassin, Jean‐Benoit

Subjects
Life Below Water, foraging behavior, Mirounga leonina, physical oceanography, population status, sea ice, Southern Ocean water masses, Ecological Applications, Ecology, Zoology
Published
2016

14. Corrigendum : Envisioning the Future of Aquatic Animal Tracking: Technology, Science, and Application

Author

LENNOX, ROBERT J., AARESTRUP, KIM, COOKE, STEVEN J., COWLEY, PAUL D., DENG, ZHIQUN D., FISK, AARON T., HARCOURT, ROBERT G., HEUPEL, MICHELLE, HINCH, SCOTT G., HOLLAND, KIM N., HUSSEY, NIGEL E., IVERSON, SARA J., KESSEL, STEVEN T., KOCIK, JOHN F., LUCAS, MARTYN C., FLEMMING, JOANNA MILLS, NGUYEN, VIVIAN M., STOKESBURY, MICHAEL J.W., VAGLE, SVEIN, VANDERZWAAG, DAVID L., WHORISKEY, FREDERICK G., and YOUNG, NATHAN

Published
2017

15. Envisioning the Future of Aquatic Animal Tracking : Technology, Science, and Application

Author

LENNOX, ROBERT J., AARESTRUP, KIM, COOKE, STEVEN J., COWLEY, PAUL D., DENG, ZHIQUN D., FISK, AARON T., HARCOURT, ROBERT G., HEUPEL, MICHELLE, HINCH, SCOTT G., HOLLAND, KIM N., HUSSEY, NIGEL E., IVERSON, SARA J., KESSEL, STEVEN T., KOCIK, JOHN F., LUCAS, MARTYN C., FLEMMING, JOANNA MILLS, NGUYEN, VIVIAN M., STOKESBURY, MICHAEL J.W., VAGLE, SVEIN, VANDERZWAAG, DAVID L., WHORISKEY, FREDERICK G., and YOUNG, NATHAN

Published
2017

16. Ocean Observations Using Tagged Animals

Author

Roquet, Fabien, Boehme, Lars, Block, Barbara, Charrassin, Jean-Benoit, Costa, Daniel, Guinet, Christophe, Harcourt, Robert G., Hindell, Mark A., Hückstädt, Luis A., McMahon, Clive R., Woodward, Bill, and Fedak, Mike A.

Published
2017

17. Marine Mammals Exploring the Oceans Pole to Pole : A Review of the MEOP Consortium

Author

Treasure, Anne M., Roquet, Fabien, Ansorge, Isabelle J., Bester, Marthán N., Boehme, Lars, Bornemann, Horst, Charrassin, Jean-Benoit, Chevallier, Damien, Costa, Daniel P., Fedak, Mike A., Guinet, Christophe, Hammill, Mike O., Harcourt, Robert G., Hindell, Mark A., Kovacs, Kit M., Lea, Mary-Anne, Lovell, Phil, Lowther, Andrew D., Lydersen, Christian, McIntyre, Trevor, McMahon, Clive R., Muelbert, Mônica M.C., Nicholls, Keith, Picard, Baptiste, Reverdin, Gilles, Trites, Andrew W., Williams, Guy D., and de Bruyn, P.J. Nico

Published
2017

23. Scaling of Activity Space in Marine Organisms across Latitudinal Gradients

Author

Udyawer, Vinay, Huveneers, Charlie, Jaine, Fabrice, Babcock, Russell C., Brodie, Stephanie, Buscot, Marie-jeanne, Campbell, Hamish A., Harcourt, Robert G., Hoenner, Xavier, Lédée, Elodie J. I., Simpfendorfer, Colin A., Taylor, Matthew D., Armstrong, Asia, Barnett, Adam, Brown, Culum, Bruce, Barry, Butcher, Paul A., Cadiou, Gwenael, Couturier, Lydie I. E., Currey-randall, Leanne, Drew, Michael, Dudgeon, Christine L., Dwyer, Ross G., Espinoza, Mario, Ferreira, Luciana C., Fowler, Anthony, Harasti, David, Harborne, Alastair R., Knott, Nathan A., Lee, Kate, Lloyd, Matt, Lowry, Michael, Marzullo, Teagan, Matley, Jordan, Mcallister, Jaime D., Mcauley, Rory, Mcgregor, Frazer, Meekan, Mark, Mills, Kade, Norman, Bradley M., Oh, Beverly, Payne, Nicholas L., Peddemors, Vic, Piddocke, Toby, Pillans, Richard D., Reina, Richard D., Rogers, Paul, Semmens, Jayson M., Smoothey, Amy, Speed, Conrad W., Van Der Meulen, Dylan, Heupel, Michelle R., Udyawer, Vinay, Huveneers, Charlie, Jaine, Fabrice, Babcock, Russell C., Brodie, Stephanie, Buscot, Marie-jeanne, Campbell, Hamish A., Harcourt, Robert G., Hoenner, Xavier, Lédée, Elodie J. I., Simpfendorfer, Colin A., Taylor, Matthew D., Armstrong, Asia, Barnett, Adam, Brown, Culum, Bruce, Barry, Butcher, Paul A., Cadiou, Gwenael, Couturier, Lydie I. E., Currey-randall, Leanne, Drew, Michael, Dudgeon, Christine L., Dwyer, Ross G., Espinoza, Mario, Ferreira, Luciana C., Fowler, Anthony, Harasti, David, Harborne, Alastair R., Knott, Nathan A., Lee, Kate, Lloyd, Matt, Lowry, Michael, Marzullo, Teagan, Matley, Jordan, Mcallister, Jaime D., Mcauley, Rory, Mcgregor, Frazer, Meekan, Mark, Mills, Kade, Norman, Bradley M., Oh, Beverly, Payne, Nicholas L., Peddemors, Vic, Piddocke, Toby, Pillans, Richard D., Reina, Richard D., Rogers, Paul, Semmens, Jayson M., Smoothey, Amy, Speed, Conrad W., Van Der Meulen, Dylan, and Heupel, Michelle R.

Abstract

Unifying models have shown that the amount of space used by animals (e.g., activity space, home range) scales allometrically with body mass for terrestrial taxa; however, such relationships are far less clear for marine species. We compiled movement data from 1,596 individuals across 79 taxa collected using a continental passive acoustic telemetry network of acoustic receivers to assess allometric scaling of activity space. We found that ectothermic marine taxa do exhibit allometric scaling for activity space, with an overall scaling exponent of 0.64. However, body mass alone explained only 35% of the variation, with the remaining variation best explained by trophic position for teleosts and latitude for sharks, rays, and marine reptiles. Taxon-specific allometric relationships highlighted weaker scaling exponents among teleost fish species (0.07) than sharks (0.96), rays (0.55), and marine reptiles (0.57). The allometric scaling relationship and scaling exponents for the marine taxonomic groups examined were lower than those reported from studies that had collated both marine and terrestrial species data derived using various tracking methods. We propose that these disparities arise because previous work integrated summarized data across many studies that used differing methods for collecting and quantifying activity space, introducing considerable uncertainty into slope estimates. Our findings highlight the benefit of using large-scale, coordinated animal biotelemetry networks to address cross-taxa evolutionary and ecological questions.

Published
2023
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24. Scaling of Activity Space in Marine Organisms across Latitudinal Gradients

Author

Udyawer, Vinay, primary, Huveneers, Charlie, additional, Jaine, Fabrice, additional, Babcock, Russell C., additional, Brodie, Stephanie, additional, Buscot, Marie-Jeanne, additional, Campbell, Hamish A., additional, Harcourt, Robert G., additional, Hoenner, Xavier, additional, Lédée, Elodie J. I., additional, Simpfendorfer, Colin A., additional, Taylor, Matthew D., additional, Armstrong, Asia, additional, Barnett, Adam, additional, Brown, Culum, additional, Bruce, Barry, additional, Butcher, Paul A., additional, Cadiou, Gwenael, additional, Couturier, Lydie I. E., additional, Currey-Randall, Leanne, additional, Drew, Michael, additional, Dudgeon, Christine L., additional, Dwyer, Ross G., additional, Espinoza, Mario, additional, Ferreira, Luciana C., additional, Fowler, Anthony, additional, Harasti, David, additional, Harborne, Alastair R., additional, Knott, Nathan A., additional, Lee, Kate, additional, Lloyd, Matt, additional, Lowry, Michael, additional, Marzullo, Teagan, additional, Matley, Jordan, additional, McAllister, Jaime D., additional, McAuley, Rory, additional, McGregor, Frazer, additional, Meekan, Mark, additional, Mills, Kade, additional, Norman, Bradley M., additional, Oh, Beverly, additional, Payne, Nicholas L., additional, Peddemors, Vic, additional, Piddocke, Toby, additional, Pillans, Richard D., additional, Reina, Richard D., additional, Rogers, Paul, additional, Semmens, Jayson M., additional, Smoothey, Amy, additional, Speed, Conrad W., additional, van der Meulen, Dylan, additional, and Heupel, Michelle R., additional

Published
2023
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49. Marine mammal conservation: over the horizon

Author

Nelms, Sarah E., Alfaro-Shigueto, Joanna, Arnould, John P. Y., Avila, Isabel C., Bengtson Nash, Susan, Campbell, Elizabeth, Carter, Matt I. D., Collins, Timothy, Currey, Rohan J. C., Domit, Camila, Franco-Trecu, Valentina, Fuentes, Mariana M. P. B., Gilman, Eric, Harcourt, Robert G., Hines, Ellen M., Hoelzel, A. Rus, Hooker, Sascha K., Johnston, David W., Kelkar, Nachiket, Kiszka, Jermy J., Laidre, Kristin L., Mangel, Jeffrey C., Marsh, Helene, Maxwell, Sara M., Onoufriou, Aubrie B., Palacios, Daniel M., Pierce, Graham J., Ponnampalam, Louisa S., Porter, Lindsay J., Russell, Debbie J. F., Stockin, Karen, Sutaria, Dipani, Wambiji, Nina, Weir, Caroline R., Wilson, Ben, and Godley, Brendan J.

Subjects
Marine mammals, Priority setting, Research techniques, Conservation, Threats, Management
Abstract

35 pages, 3 figures.-- Open access 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 S.E.N. acknowledges funding from the Natural Environment Research Council (NE/L002434/1). S.E.N. and B.J.G. also acknowledge support from the European Union (INDICIT; EU grant agreement no. 110661/ 2018/ 794561/ SUB/ENV. C2). E.C. has a doctoral fellowship from the World Wildlife Foundation - Education for Nature. M.I.D.C. was supported by the UK Department for Business and Industrial Strategy (BEIS; project number OESEA-16-78). D.J.F.R. was supported by National Capability funding from the UK Natural Environment Research Council (NERC) to the Sea Mammal Research Unit (SMRU) (grant no. SMRU1001). A.B.O. acknowledges funding from the Office of Naval Research (award no. N000141613017). D.M.P. was supported by the Whale Habitat Professorship Endowment Fund, Marine Mammal Institute, Oregon State University. K.A.S. was supported by a Royal Society of New Zealand Te Aparangi Rutherford Discovery Fellowship

Published
2021

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