Rebuilding beluga stocks in West Greenland
Decisions about sustainable exploitation levels of marine resources are often based on inadequate data, but are nevertheless required for practical purposes. We describe one exception where abundance estimates spanning 30 years and catch data spanning more than 40 years were used in a Bayesian asses...
Published in: | Animal Conservation |
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Main Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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2017
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Online Access: | https://risweb.st-andrews.ac.uk/portal/en/researchoutput/rebuilding-beluga-stocks-in-west-greenland(1dc72875-465a-47f2-8a8e-14038ea88914).html https://doi.org/10.1111/acv.12315 https://research-repository.st-andrews.ac.uk/bitstream/10023/10882/1/Borchers_2017_AC_BelugaStocks_CC.pdf http://onlinelibrary.wiley.com/doi/10.1111/acv.12315/full#footer-support-info |
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ftunstandrewcris:oai:risweb.st-andrews.ac.uk:publications/1dc72875-465a-47f2-8a8e-14038ea88914 2023-05-15T15:41:42+02:00 Rebuilding beluga stocks in West Greenland Heide-Jørgensen, M. P. Hansen, R. G. Fossette, S. Nielsen, N. H. Borchers, D. L. Stern, H. Witting, L. 2017-06 application/pdf https://risweb.st-andrews.ac.uk/portal/en/researchoutput/rebuilding-beluga-stocks-in-west-greenland(1dc72875-465a-47f2-8a8e-14038ea88914).html https://doi.org/10.1111/acv.12315 https://research-repository.st-andrews.ac.uk/bitstream/10023/10882/1/Borchers_2017_AC_BelugaStocks_CC.pdf http://onlinelibrary.wiley.com/doi/10.1111/acv.12315/full#footer-support-info eng eng info:eu-repo/semantics/openAccess Heide-Jørgensen , M P , Hansen , R G , Fossette , S , Nielsen , N H , Borchers , D L , Stern , H & Witting , L 2017 , ' Rebuilding beluga stocks in West Greenland ' , Animal Conservation , vol. 20 , no. 3 , pp. 282-293 . https://doi.org/10.1111/acv.12315 Aerial survey Bayesian assessment Hidden Markov model Line transect Beluga Sea ice cover Abundance estimates Cetaceans article 2017 ftunstandrewcris https://doi.org/10.1111/acv.12315 2022-10-13T15:26:06Z Decisions about sustainable exploitation levels of marine resources are often based on inadequate data, but are nevertheless required for practical purposes. We describe one exception where abundance estimates spanning 30 years and catch data spanning more than 40 years were used in a Bayesian assessment model of belugas Delphinapterus leucas off West Greenland. The model was updated with data from a visual aerial survey on the wintering ground in 2012. Methods that take account of stochastic animal availability by using independent estimates of forward and perpendicular sighting distances were used to estimate beluga abundance. A model that appears to be robust to the presence of a few large groups yielded an estimate of 7456 belugas (cv = 0.44), similar to a conventional distance-sampling estimate. A mark–recapture distance analysis that corrects for perception and availability bias estimated the abundance to be 9072 whales (cv = 0.32). Increasing distance of beluga sightings from shore was correlated with decreasing sea ice cover, suggesting that belugas expand their distribution offshore (i.e. westward in this context) with the reduction of coastal sea ice. A model with high (0.98) adult survival estimated a decline from 18 600 (90% CI: 13 400, 26 000) whales in 1970 to 8000 (90% CI: 5830, 11 200) in 2004. The decline was probably a result of a period with exceptionally large catches. Following the introduction of catch limits in 2004, the model projects an increase to 11 600 (90% CI: 6760, 17 600) individuals in 2020 (assuming annual removals of 294 belugas after 2014). If the annual removal level is fixed at 300 individuals, a low-survival (0.97) model predicts a 75% probability of an increasing population during 2015–2020. Reduced removal rates due to catch limits and the more offshore, less accessible distribution of the whales are believed to be responsible for the initial signs of population recovery. Article in Journal/Newspaper Beluga Beluga* Delphinapterus leucas Greenland Sea ice University of St Andrews: Research Portal Greenland Animal Conservation 20 3 282 293 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
topic |
Aerial survey Bayesian assessment Hidden Markov model Line transect Beluga Sea ice cover Abundance estimates Cetaceans |
spellingShingle |
Aerial survey Bayesian assessment Hidden Markov model Line transect Beluga Sea ice cover Abundance estimates Cetaceans Heide-Jørgensen, M. P. Hansen, R. G. Fossette, S. Nielsen, N. H. Borchers, D. L. Stern, H. Witting, L. Rebuilding beluga stocks in West Greenland |
topic_facet |
Aerial survey Bayesian assessment Hidden Markov model Line transect Beluga Sea ice cover Abundance estimates Cetaceans |
description |
Decisions about sustainable exploitation levels of marine resources are often based on inadequate data, but are nevertheless required for practical purposes. We describe one exception where abundance estimates spanning 30 years and catch data spanning more than 40 years were used in a Bayesian assessment model of belugas Delphinapterus leucas off West Greenland. The model was updated with data from a visual aerial survey on the wintering ground in 2012. Methods that take account of stochastic animal availability by using independent estimates of forward and perpendicular sighting distances were used to estimate beluga abundance. A model that appears to be robust to the presence of a few large groups yielded an estimate of 7456 belugas (cv = 0.44), similar to a conventional distance-sampling estimate. A mark–recapture distance analysis that corrects for perception and availability bias estimated the abundance to be 9072 whales (cv = 0.32). Increasing distance of beluga sightings from shore was correlated with decreasing sea ice cover, suggesting that belugas expand their distribution offshore (i.e. westward in this context) with the reduction of coastal sea ice. A model with high (0.98) adult survival estimated a decline from 18 600 (90% CI: 13 400, 26 000) whales in 1970 to 8000 (90% CI: 5830, 11 200) in 2004. The decline was probably a result of a period with exceptionally large catches. Following the introduction of catch limits in 2004, the model projects an increase to 11 600 (90% CI: 6760, 17 600) individuals in 2020 (assuming annual removals of 294 belugas after 2014). If the annual removal level is fixed at 300 individuals, a low-survival (0.97) model predicts a 75% probability of an increasing population during 2015–2020. Reduced removal rates due to catch limits and the more offshore, less accessible distribution of the whales are believed to be responsible for the initial signs of population recovery. |
format |
Article in Journal/Newspaper |
author |
Heide-Jørgensen, M. P. Hansen, R. G. Fossette, S. Nielsen, N. H. Borchers, D. L. Stern, H. Witting, L. |
author_facet |
Heide-Jørgensen, M. P. Hansen, R. G. Fossette, S. Nielsen, N. H. Borchers, D. L. Stern, H. Witting, L. |
author_sort |
Heide-Jørgensen, M. P. |
title |
Rebuilding beluga stocks in West Greenland |
title_short |
Rebuilding beluga stocks in West Greenland |
title_full |
Rebuilding beluga stocks in West Greenland |
title_fullStr |
Rebuilding beluga stocks in West Greenland |
title_full_unstemmed |
Rebuilding beluga stocks in West Greenland |
title_sort |
rebuilding beluga stocks in west greenland |
publishDate |
2017 |
url |
https://risweb.st-andrews.ac.uk/portal/en/researchoutput/rebuilding-beluga-stocks-in-west-greenland(1dc72875-465a-47f2-8a8e-14038ea88914).html https://doi.org/10.1111/acv.12315 https://research-repository.st-andrews.ac.uk/bitstream/10023/10882/1/Borchers_2017_AC_BelugaStocks_CC.pdf http://onlinelibrary.wiley.com/doi/10.1111/acv.12315/full#footer-support-info |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Beluga Beluga* Delphinapterus leucas Greenland Sea ice |
genre_facet |
Beluga Beluga* Delphinapterus leucas Greenland Sea ice |
op_source |
Heide-Jørgensen , M P , Hansen , R G , Fossette , S , Nielsen , N H , Borchers , D L , Stern , H & Witting , L 2017 , ' Rebuilding beluga stocks in West Greenland ' , Animal Conservation , vol. 20 , no. 3 , pp. 282-293 . https://doi.org/10.1111/acv.12315 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1111/acv.12315 |
container_title |
Animal Conservation |
container_volume |
20 |
container_issue |
3 |
container_start_page |
282 |
op_container_end_page |
293 |
_version_ |
1766374589599842304 |