Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines.
1. Harbour seals Phoca vitulina in eastern England were heavily exploited in the 1960s and 1970s, and affected by phocine distemper virus (PDV) epidemics in 1988 and 2002. Information on their historical and current status is required for their management. To maximize the effectiveness of limited po...
Published in: | Journal of Applied Ecology |
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Language: | English |
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2005
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Online Access: | https://research-portal.st-andrews.ac.uk/en/researchoutput/population-dynamics-of-harbour-seals-phoca-vitulina-in-england-growth-and-catastrophic-declines(c993642a-d492-46fe-9b7e-acb13d327cb3).html https://doi.org/10.1111/j.1365-2664.2005.01025.x http://www.scopus.com/inward/record.url?scp=28244478530&partnerID=8YFLogxK |
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ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/c993642a-d492-46fe-9b7e-acb13d327cb3 2024-09-15T18:10:46+00:00 Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. Thompson, David Lonergan, Michael Edward Duck, Callan David 2005-08 https://research-portal.st-andrews.ac.uk/en/researchoutput/population-dynamics-of-harbour-seals-phoca-vitulina-in-england-growth-and-catastrophic-declines(c993642a-d492-46fe-9b7e-acb13d327cb3).html https://doi.org/10.1111/j.1365-2664.2005.01025.x http://www.scopus.com/inward/record.url?scp=28244478530&partnerID=8YFLogxK eng eng https://research-portal.st-andrews.ac.uk/en/researchoutput/population-dynamics-of-harbour-seals-phoca-vitulina-in-england-growth-and-catastrophic-declines(c993642a-d492-46fe-9b7e-acb13d327cb3).html info:eu-repo/semantics/restrictedAccess Thompson , D , Lonergan , M E & Duck , C D 2005 , ' Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. ' , Journal of Applied Ecology , vol. 42 , no. 4 , pp. 638-648 . https://doi.org/10.1111/j.1365-2664.2005.01025.x air survey epidemic mortality phocine distemper state-space model STATE-SPACE MODELS COMMON SEALS WADDEN SEA KATTEGAT-SKAGERRAK DISTEMPER ORGANOCHLORINE EPIZOOTIOLOGY ABUNDANCE DISEASE DEATHS article 2005 ftunstandrewcris https://doi.org/10.1111/j.1365-2664.2005.01025.x 2024-08-14T23:40:02Z 1. Harbour seals Phoca vitulina in eastern England were heavily exploited in the 1960s and 1970s, and affected by phocine distemper virus (PDV) epidemics in 1988 and 2002. Information on their historical and current status is required for their management. To maximize the effectiveness of limited population survey effort we need to both estimate and minimize error. 2. Presented here are data from annual aerial surveys of the population. Sporadic, synoptic surveys in The Wash, England, were used with more frequent counts of subpopulations in the Moray Firth, Scotland, to determine optimum timing of surveys. 3. We developed models that explicitly account for variability in both observation and population growth processes to show that the proportion of animals observed is much more variable than the annual growth rates. The latter can therefore be treated as constant within each period, and estimated along with the epidemic mortalities during the study and the precision of the survey results. 4. The Wash population increased at around 3.1% per annum (pa) [95% confidence interval (CI) 2.1-4.1] between 1973 and 1988. It fell by approximately 52% (95% CI 44-59) as a result of the 1988 PDV epidemic, and subsequently increased at 5.7% pa (95% CI 4.8-6.7). These growth rates were below those reported for European mainland populations, but showed no indication of density-dependent effects. 5. The recurrence of PDV in 2002 caused approximately 22% mortality (95% CI 9-33), significantly less than the 1988 epidemic and less than half that in European mainland populations in 2002. 6. Synthesis and applications. Combining sparse, systematic survey data with sporadic counts produced robust estimates of growth rates and epidemic mortality. The results indicate the value of even limited and sporadic survey effort for monitoring populations. The study has highlighted significant differences in both population dynamics and the severity of disease events between English and European harbour seal populations. Article in Journal/Newspaper harbour seal Phoca vitulina University of St Andrews: Research Portal Journal of Applied Ecology 42 4 638 648 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
topic |
air survey epidemic mortality phocine distemper state-space model STATE-SPACE MODELS COMMON SEALS WADDEN SEA KATTEGAT-SKAGERRAK DISTEMPER ORGANOCHLORINE EPIZOOTIOLOGY ABUNDANCE DISEASE DEATHS |
spellingShingle |
air survey epidemic mortality phocine distemper state-space model STATE-SPACE MODELS COMMON SEALS WADDEN SEA KATTEGAT-SKAGERRAK DISTEMPER ORGANOCHLORINE EPIZOOTIOLOGY ABUNDANCE DISEASE DEATHS Thompson, David Lonergan, Michael Edward Duck, Callan David Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. |
topic_facet |
air survey epidemic mortality phocine distemper state-space model STATE-SPACE MODELS COMMON SEALS WADDEN SEA KATTEGAT-SKAGERRAK DISTEMPER ORGANOCHLORINE EPIZOOTIOLOGY ABUNDANCE DISEASE DEATHS |
description |
1. Harbour seals Phoca vitulina in eastern England were heavily exploited in the 1960s and 1970s, and affected by phocine distemper virus (PDV) epidemics in 1988 and 2002. Information on their historical and current status is required for their management. To maximize the effectiveness of limited population survey effort we need to both estimate and minimize error. 2. Presented here are data from annual aerial surveys of the population. Sporadic, synoptic surveys in The Wash, England, were used with more frequent counts of subpopulations in the Moray Firth, Scotland, to determine optimum timing of surveys. 3. We developed models that explicitly account for variability in both observation and population growth processes to show that the proportion of animals observed is much more variable than the annual growth rates. The latter can therefore be treated as constant within each period, and estimated along with the epidemic mortalities during the study and the precision of the survey results. 4. The Wash population increased at around 3.1% per annum (pa) [95% confidence interval (CI) 2.1-4.1] between 1973 and 1988. It fell by approximately 52% (95% CI 44-59) as a result of the 1988 PDV epidemic, and subsequently increased at 5.7% pa (95% CI 4.8-6.7). These growth rates were below those reported for European mainland populations, but showed no indication of density-dependent effects. 5. The recurrence of PDV in 2002 caused approximately 22% mortality (95% CI 9-33), significantly less than the 1988 epidemic and less than half that in European mainland populations in 2002. 6. Synthesis and applications. Combining sparse, systematic survey data with sporadic counts produced robust estimates of growth rates and epidemic mortality. The results indicate the value of even limited and sporadic survey effort for monitoring populations. The study has highlighted significant differences in both population dynamics and the severity of disease events between English and European harbour seal populations. |
format |
Article in Journal/Newspaper |
author |
Thompson, David Lonergan, Michael Edward Duck, Callan David |
author_facet |
Thompson, David Lonergan, Michael Edward Duck, Callan David |
author_sort |
Thompson, David |
title |
Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. |
title_short |
Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. |
title_full |
Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. |
title_fullStr |
Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. |
title_full_unstemmed |
Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. |
title_sort |
population dynamics of harbour seals ( phoca vitulina ) in england: growth and catastrophic declines. |
publishDate |
2005 |
url |
https://research-portal.st-andrews.ac.uk/en/researchoutput/population-dynamics-of-harbour-seals-phoca-vitulina-in-england-growth-and-catastrophic-declines(c993642a-d492-46fe-9b7e-acb13d327cb3).html https://doi.org/10.1111/j.1365-2664.2005.01025.x http://www.scopus.com/inward/record.url?scp=28244478530&partnerID=8YFLogxK |
genre |
harbour seal Phoca vitulina |
genre_facet |
harbour seal Phoca vitulina |
op_source |
Thompson , D , Lonergan , M E & Duck , C D 2005 , ' Population dynamics of harbour seals ( Phoca vitulina ) in England: growth and catastrophic declines. ' , Journal of Applied Ecology , vol. 42 , no. 4 , pp. 638-648 . https://doi.org/10.1111/j.1365-2664.2005.01025.x |
op_relation |
https://research-portal.st-andrews.ac.uk/en/researchoutput/population-dynamics-of-harbour-seals-phoca-vitulina-in-england-growth-and-catastrophic-declines(c993642a-d492-46fe-9b7e-acb13d327cb3).html |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1111/j.1365-2664.2005.01025.x |
container_title |
Journal of Applied Ecology |
container_volume |
42 |
container_issue |
4 |
container_start_page |
638 |
op_container_end_page |
648 |
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1810448349434740736 |