Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020)
To support sustainable management of apex predator populations, it is important to estimate population size and understand the drivers of population trends to anticipate the consequences of human decisions. Robust population models are needed, which must be based on realistic biological principles a...
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North Atlantic Marine Mammal Commission
2021
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Online Access: | https://research.wur.nl/en/publications/report-of-the-nammco-ices-workshop-on-seal-modelling-wkseals-2020 https://doi.org/10.7557/3.5794 |
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ftunivwagenin:oai:library.wur.nl:wurpubs/611833 2024-04-28T08:16:51+00:00 Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020) Smout, Sophie Murray, Kimberly Aarts, G.M. Biuw, Martin Brasseur, S.M.J.M. Buren, Alejandro Empacher, Fanny Frie, Anne Kirstine Grecian, James Hammill, Mike Mikkelsen, Bjarni Mosnier, Arnaud Rosing-Asvid, Aqqalu Russell, Debbie Skaug, Hans Stenson, Garry Thomas, Len ver Hoef, Jay Witting, Lars Zabavnikov, Vladimir Oigard, Tor Arne Fernandez, Ruth Wickson, Fern 2021 application/pdf https://research.wur.nl/en/publications/report-of-the-nammco-ices-workshop-on-seal-modelling-wkseals-2020 https://doi.org/10.7557/3.5794 en eng North Atlantic Marine Mammal Commission https://edepot.wur.nl/589093 https://research.wur.nl/en/publications/report-of-the-nammco-ices-workshop-on-seal-modelling-wkseals-2020 doi:10.7557/3.5794 https://creativecommons.org/licenses/by/4.0/ Wageningen University & Research Life Science External research report 2021 ftunivwagenin https://doi.org/10.7557/3.5794 2024-04-03T14:44:43Z To support sustainable management of apex predator populations, it is important to estimate population size and understand the drivers of population trends to anticipate the consequences of human decisions. Robust population models are needed, which must be based on realistic biological principles and validated with the best available data. A team of international experts reviewed age-structured models of North Atlantic pinniped populations, including Grey seal (Halichoerus grypus), Harp seal (Pagophilus groenlandicus), and Hooded seal (Cystophora cristata). Statistical methods used to fit such models to data were compared and contrasted. Differences in biological assumptions and model equations were driven by the data available from separate studies, including observation methodology and pre-processing. Counts of pups during the breeding season were used in all models, with additional counts of adults and juveniles available in some. The regularity and frequency of data collection, including survey counts and vital rate estimates, varied. Important differences between the models concerned the nature and causes of variation in vital rates (age-dependent survival and fecundity). Parameterisation of age at maturity was detailed and time-dependent in some models and simplified in others. Methods for estimation of model parameters were reviewed and compared. They included Bayesian and maximum likelihood (ML) approaches, implemented via bespoke coding in C, C++, TMB or JAGS. Comparative model runs suggested that as expected, ML-based implementations were rapid and computationally efficient, while Bayesian approaches, which used MCMC or sequential importance sampling, required longer for inference. For grey seal populations in the Netherlands, where preliminary ML-based TMB results were compared with the outputs of a Bayesian JAGS implementation, some differences in parameter estimates were apparent. For these seal populations, further investigations are recommended to explore differences that might result from the ... Report Cystophora cristata Harp Seal hooded seal North Atlantic Pagophilus groenlandicus Wageningen UR (University & Research Centre): Digital Library NAMMCO Scientific Publications 12 1 |
institution |
Open Polar |
collection |
Wageningen UR (University & Research Centre): Digital Library |
op_collection_id |
ftunivwagenin |
language |
English |
topic |
Life Science |
spellingShingle |
Life Science Smout, Sophie Murray, Kimberly Aarts, G.M. Biuw, Martin Brasseur, S.M.J.M. Buren, Alejandro Empacher, Fanny Frie, Anne Kirstine Grecian, James Hammill, Mike Mikkelsen, Bjarni Mosnier, Arnaud Rosing-Asvid, Aqqalu Russell, Debbie Skaug, Hans Stenson, Garry Thomas, Len ver Hoef, Jay Witting, Lars Zabavnikov, Vladimir Oigard, Tor Arne Fernandez, Ruth Wickson, Fern Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020) |
topic_facet |
Life Science |
description |
To support sustainable management of apex predator populations, it is important to estimate population size and understand the drivers of population trends to anticipate the consequences of human decisions. Robust population models are needed, which must be based on realistic biological principles and validated with the best available data. A team of international experts reviewed age-structured models of North Atlantic pinniped populations, including Grey seal (Halichoerus grypus), Harp seal (Pagophilus groenlandicus), and Hooded seal (Cystophora cristata). Statistical methods used to fit such models to data were compared and contrasted. Differences in biological assumptions and model equations were driven by the data available from separate studies, including observation methodology and pre-processing. Counts of pups during the breeding season were used in all models, with additional counts of adults and juveniles available in some. The regularity and frequency of data collection, including survey counts and vital rate estimates, varied. Important differences between the models concerned the nature and causes of variation in vital rates (age-dependent survival and fecundity). Parameterisation of age at maturity was detailed and time-dependent in some models and simplified in others. Methods for estimation of model parameters were reviewed and compared. They included Bayesian and maximum likelihood (ML) approaches, implemented via bespoke coding in C, C++, TMB or JAGS. Comparative model runs suggested that as expected, ML-based implementations were rapid and computationally efficient, while Bayesian approaches, which used MCMC or sequential importance sampling, required longer for inference. For grey seal populations in the Netherlands, where preliminary ML-based TMB results were compared with the outputs of a Bayesian JAGS implementation, some differences in parameter estimates were apparent. For these seal populations, further investigations are recommended to explore differences that might result from the ... |
format |
Report |
author |
Smout, Sophie Murray, Kimberly Aarts, G.M. Biuw, Martin Brasseur, S.M.J.M. Buren, Alejandro Empacher, Fanny Frie, Anne Kirstine Grecian, James Hammill, Mike Mikkelsen, Bjarni Mosnier, Arnaud Rosing-Asvid, Aqqalu Russell, Debbie Skaug, Hans Stenson, Garry Thomas, Len ver Hoef, Jay Witting, Lars Zabavnikov, Vladimir Oigard, Tor Arne Fernandez, Ruth Wickson, Fern |
author_facet |
Smout, Sophie Murray, Kimberly Aarts, G.M. Biuw, Martin Brasseur, S.M.J.M. Buren, Alejandro Empacher, Fanny Frie, Anne Kirstine Grecian, James Hammill, Mike Mikkelsen, Bjarni Mosnier, Arnaud Rosing-Asvid, Aqqalu Russell, Debbie Skaug, Hans Stenson, Garry Thomas, Len ver Hoef, Jay Witting, Lars Zabavnikov, Vladimir Oigard, Tor Arne Fernandez, Ruth Wickson, Fern |
author_sort |
Smout, Sophie |
title |
Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020) |
title_short |
Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020) |
title_full |
Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020) |
title_fullStr |
Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020) |
title_full_unstemmed |
Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020) |
title_sort |
report of the nammco-ices workshop on seal modelling (wkseals 2020) |
publisher |
North Atlantic Marine Mammal Commission |
publishDate |
2021 |
url |
https://research.wur.nl/en/publications/report-of-the-nammco-ices-workshop-on-seal-modelling-wkseals-2020 https://doi.org/10.7557/3.5794 |
genre |
Cystophora cristata Harp Seal hooded seal North Atlantic Pagophilus groenlandicus |
genre_facet |
Cystophora cristata Harp Seal hooded seal North Atlantic Pagophilus groenlandicus |
op_relation |
https://edepot.wur.nl/589093 https://research.wur.nl/en/publications/report-of-the-nammco-ices-workshop-on-seal-modelling-wkseals-2020 doi:10.7557/3.5794 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ Wageningen University & Research |
op_doi |
https://doi.org/10.7557/3.5794 |
container_title |
NAMMCO Scientific Publications |
container_volume |
12 |
container_issue |
1 |
_version_ |
1797581784157782016 |