Seals, sandeels and salmon:diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland
Harbour seal populations have declined by up to 40% around northern and eastern Britain since 2000 due to unknown causes; prey availability is one important factor that could be contributing to the decline. We estimate the diet and prey consumption of a population of harbour seals in southeast Scotl...
Published in: | Marine Ecology Progress Series |
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Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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2009
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Online Access: | https://research-portal.st-andrews.ac.uk/en/researchoutput/seals-sandeels-and-salmon(767fcec2-07cd-4a85-ad85-23bb4a7d380d).html https://doi.org/10.3354/meps08232 https://research-repository.st-andrews.ac.uk/bitstream/10023/4057/1/Sharples2009MarEcolProgSer390p265_Seals.pdf http://www.scopus.com/inward/record.url?scp=70349550019&partnerID=8YFLogxK |
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ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/767fcec2-07cd-4a85-ad85-23bb4a7d380d 2024-06-23T07:53:31+00:00 Seals, sandeels and salmon:diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland Sharples, Ruth Jemma Arrizabalaga, B Hammond, Philip Steven 2009 application/pdf https://research-portal.st-andrews.ac.uk/en/researchoutput/seals-sandeels-and-salmon(767fcec2-07cd-4a85-ad85-23bb4a7d380d).html https://doi.org/10.3354/meps08232 https://research-repository.st-andrews.ac.uk/bitstream/10023/4057/1/Sharples2009MarEcolProgSer390p265_Seals.pdf http://www.scopus.com/inward/record.url?scp=70349550019&partnerID=8YFLogxK eng eng https://research-portal.st-andrews.ac.uk/en/researchoutput/seals-sandeels-and-salmon(767fcec2-07cd-4a85-ad85-23bb4a7d380d).html info:eu-repo/semantics/openAccess Sharples , R J , Arrizabalaga , B & Hammond , P S 2009 , ' Seals, sandeels and salmon : diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland ' , Marine Ecology Progress Series , vol. 390 , pp. 265-276 . https://doi.org/10.3354/meps08232 Faecal sampling Fisheries North Sea Prey availability Phoca vitulina Special Area of Conservation article 2009 ftunstandrewcris https://doi.org/10.3354/meps08232 2024-06-13T00:22:24Z Harbour seal populations have declined by up to 40% around northern and eastern Britain since 2000 due to unknown causes; prey availability is one important factor that could be contributing to the decline. We estimate the diet and prey consumption of a population of harbour seals in southeast Scotland, using analysis of hard prey remains recovered from scats, to investigate change in the importance of sandeels over 6 yr spanning the local sandeel fishery closure. The study site includes Special Areas of Conservation for harbour seals as well as vulnerable salmon stocks. We estimate the extent of harbour seal predation on salmon in the area. In St. Andrews Bay, harbour seal diet was heavily dominated by sandeels, especially in winter and spring. Gadoids (whiting, cod) and flatfish (dab, plaice, flounder) were the other main prey. The proportion of sandeels in the diet was remarkably consistent over time (71 to 77%), but the average size of sandeels consumed increased following the closure of the fishery. In the Firth of Tay, sandeels were prevalent in winter, but the diet in the rest of the year was dominated by salmonids: salmon comprised 64% of the diet in summer and sea trout comprised 40% of the diet in autumn. Thus marked differences in diet were evident at a fine spatial scale. The effects of the sandeel fishery closure on harbour seals were equivocal, but harbour seals that haul out in SE Scotland are clearly dependent on sandeels; re-opening the fishery could thus have a negative impact and be inadvisable. We found evidence that local harbour seal predation could be impacting salmon stocks but the high uncertainty in estimates of seal diet and salmon stock size preclude the provision of management advice at this time. Article in Journal/Newspaper harbour seal Phoca vitulina University of St Andrews: Research Portal Firth of Tay ENVELOPE(-55.567,-55.567,-63.350,-63.350) Tay ENVELOPE(-55.750,-55.750,-63.367,-63.367) Marine Ecology Progress Series 390 265 276 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
topic |
Faecal sampling Fisheries North Sea Prey availability Phoca vitulina Special Area of Conservation |
spellingShingle |
Faecal sampling Fisheries North Sea Prey availability Phoca vitulina Special Area of Conservation Sharples, Ruth Jemma Arrizabalaga, B Hammond, Philip Steven Seals, sandeels and salmon:diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland |
topic_facet |
Faecal sampling Fisheries North Sea Prey availability Phoca vitulina Special Area of Conservation |
description |
Harbour seal populations have declined by up to 40% around northern and eastern Britain since 2000 due to unknown causes; prey availability is one important factor that could be contributing to the decline. We estimate the diet and prey consumption of a population of harbour seals in southeast Scotland, using analysis of hard prey remains recovered from scats, to investigate change in the importance of sandeels over 6 yr spanning the local sandeel fishery closure. The study site includes Special Areas of Conservation for harbour seals as well as vulnerable salmon stocks. We estimate the extent of harbour seal predation on salmon in the area. In St. Andrews Bay, harbour seal diet was heavily dominated by sandeels, especially in winter and spring. Gadoids (whiting, cod) and flatfish (dab, plaice, flounder) were the other main prey. The proportion of sandeels in the diet was remarkably consistent over time (71 to 77%), but the average size of sandeels consumed increased following the closure of the fishery. In the Firth of Tay, sandeels were prevalent in winter, but the diet in the rest of the year was dominated by salmonids: salmon comprised 64% of the diet in summer and sea trout comprised 40% of the diet in autumn. Thus marked differences in diet were evident at a fine spatial scale. The effects of the sandeel fishery closure on harbour seals were equivocal, but harbour seals that haul out in SE Scotland are clearly dependent on sandeels; re-opening the fishery could thus have a negative impact and be inadvisable. We found evidence that local harbour seal predation could be impacting salmon stocks but the high uncertainty in estimates of seal diet and salmon stock size preclude the provision of management advice at this time. |
format |
Article in Journal/Newspaper |
author |
Sharples, Ruth Jemma Arrizabalaga, B Hammond, Philip Steven |
author_facet |
Sharples, Ruth Jemma Arrizabalaga, B Hammond, Philip Steven |
author_sort |
Sharples, Ruth Jemma |
title |
Seals, sandeels and salmon:diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland |
title_short |
Seals, sandeels and salmon:diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland |
title_full |
Seals, sandeels and salmon:diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland |
title_fullStr |
Seals, sandeels and salmon:diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland |
title_full_unstemmed |
Seals, sandeels and salmon:diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland |
title_sort |
seals, sandeels and salmon:diet of harbour seals in st. andrews bay and the tay estuary, southeast scotland |
publishDate |
2009 |
url |
https://research-portal.st-andrews.ac.uk/en/researchoutput/seals-sandeels-and-salmon(767fcec2-07cd-4a85-ad85-23bb4a7d380d).html https://doi.org/10.3354/meps08232 https://research-repository.st-andrews.ac.uk/bitstream/10023/4057/1/Sharples2009MarEcolProgSer390p265_Seals.pdf http://www.scopus.com/inward/record.url?scp=70349550019&partnerID=8YFLogxK |
long_lat |
ENVELOPE(-55.567,-55.567,-63.350,-63.350) ENVELOPE(-55.750,-55.750,-63.367,-63.367) |
geographic |
Firth of Tay Tay |
geographic_facet |
Firth of Tay Tay |
genre |
harbour seal Phoca vitulina |
genre_facet |
harbour seal Phoca vitulina |
op_source |
Sharples , R J , Arrizabalaga , B & Hammond , P S 2009 , ' Seals, sandeels and salmon : diet of harbour seals in St. Andrews Bay and the Tay Estuary, southeast Scotland ' , Marine Ecology Progress Series , vol. 390 , pp. 265-276 . https://doi.org/10.3354/meps08232 |
op_relation |
https://research-portal.st-andrews.ac.uk/en/researchoutput/seals-sandeels-and-salmon(767fcec2-07cd-4a85-ad85-23bb4a7d380d).html |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.3354/meps08232 |
container_title |
Marine Ecology Progress Series |
container_volume |
390 |
container_start_page |
265 |
op_container_end_page |
276 |
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1802645223459782656 |