Grey seal predation mortality on three depleted stocks in the West of Scotland: What are the implications for stock assessments?
The decrease in groundfish stocks in the North Atlantic since the mid-1900s coupled with increases in grey seal (Halichoerus grypus) populations is responsible for an enduring controversy between fishers and conservationists regarding the role seals have played in stock declines. We used a Bayesian...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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Online Access: | http://dx.doi.org/10.1139/cjfas-2016-0521 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2016-0521 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2016-0521 |
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crcansciencepubl:10.1139/cjfas-2016-0521 2024-04-28T08:19:32+00:00 Grey seal predation mortality on three depleted stocks in the West of Scotland: What are the implications for stock assessments? Trijoulet, Vanessa Holmes, Steven J. Cook, Robin M. 2018 http://dx.doi.org/10.1139/cjfas-2016-0521 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2016-0521 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2016-0521 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Fisheries and Aquatic Sciences volume 75, issue 5, page 723-732 ISSN 0706-652X 1205-7533 Aquatic Science Ecology, Evolution, Behavior and Systematics journal-article 2018 crcansciencepubl https://doi.org/10.1139/cjfas-2016-0521 2024-04-02T06:55:54Z The decrease in groundfish stocks in the North Atlantic since the mid-1900s coupled with increases in grey seal (Halichoerus grypus) populations is responsible for an enduring controversy between fishers and conservationists regarding the role seals have played in stock declines. We used a Bayesian state-space model to investigate stock trends in the presence of grey seals and associated maximum sustainable yield (MSY) reference points in the West of Scotland. This study provides new estimates of seal predation mortality on haddock (Melanogrammus aeglefinus) and whiting (Merlangius merlangus) and updates the estimates for cod (Gadus morhua), which together form the traditional main components of the mixed demersal fishery in this area. Grey seal predation mortality is greatest on cod, resulting in estimates of total natural mortality higher than those used in the current ICES assessments. Seal predation mortality is low for haddock and whiting. Considering seal predation in stock assessments changes the scale of biomass and fishing mortality estimates for the three stocks. The estimates of F 0.1 and F MSY are sensitive to seal predation for cod and whiting but not for haddock. In all cases, MSY decreases with increased seal predation. Article in Journal/Newspaper Gadus morhua North Atlantic Canadian Science Publishing Canadian Journal of Fisheries and Aquatic Sciences 75 5 723 732 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
topic |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Aquatic Science Ecology, Evolution, Behavior and Systematics Trijoulet, Vanessa Holmes, Steven J. Cook, Robin M. Grey seal predation mortality on three depleted stocks in the West of Scotland: What are the implications for stock assessments? |
topic_facet |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
description |
The decrease in groundfish stocks in the North Atlantic since the mid-1900s coupled with increases in grey seal (Halichoerus grypus) populations is responsible for an enduring controversy between fishers and conservationists regarding the role seals have played in stock declines. We used a Bayesian state-space model to investigate stock trends in the presence of grey seals and associated maximum sustainable yield (MSY) reference points in the West of Scotland. This study provides new estimates of seal predation mortality on haddock (Melanogrammus aeglefinus) and whiting (Merlangius merlangus) and updates the estimates for cod (Gadus morhua), which together form the traditional main components of the mixed demersal fishery in this area. Grey seal predation mortality is greatest on cod, resulting in estimates of total natural mortality higher than those used in the current ICES assessments. Seal predation mortality is low for haddock and whiting. Considering seal predation in stock assessments changes the scale of biomass and fishing mortality estimates for the three stocks. The estimates of F 0.1 and F MSY are sensitive to seal predation for cod and whiting but not for haddock. In all cases, MSY decreases with increased seal predation. |
format |
Article in Journal/Newspaper |
author |
Trijoulet, Vanessa Holmes, Steven J. Cook, Robin M. |
author_facet |
Trijoulet, Vanessa Holmes, Steven J. Cook, Robin M. |
author_sort |
Trijoulet, Vanessa |
title |
Grey seal predation mortality on three depleted stocks in the West of Scotland: What are the implications for stock assessments? |
title_short |
Grey seal predation mortality on three depleted stocks in the West of Scotland: What are the implications for stock assessments? |
title_full |
Grey seal predation mortality on three depleted stocks in the West of Scotland: What are the implications for stock assessments? |
title_fullStr |
Grey seal predation mortality on three depleted stocks in the West of Scotland: What are the implications for stock assessments? |
title_full_unstemmed |
Grey seal predation mortality on three depleted stocks in the West of Scotland: What are the implications for stock assessments? |
title_sort |
grey seal predation mortality on three depleted stocks in the west of scotland: what are the implications for stock assessments? |
publisher |
Canadian Science Publishing |
publishDate |
2018 |
url |
http://dx.doi.org/10.1139/cjfas-2016-0521 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2016-0521 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2016-0521 |
genre |
Gadus morhua North Atlantic |
genre_facet |
Gadus morhua North Atlantic |
op_source |
Canadian Journal of Fisheries and Aquatic Sciences volume 75, issue 5, page 723-732 ISSN 0706-652X 1205-7533 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/cjfas-2016-0521 |
container_title |
Canadian Journal of Fisheries and Aquatic Sciences |
container_volume |
75 |
container_issue |
5 |
container_start_page |
723 |
op_container_end_page |
732 |
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1797582987197415424 |