Geographic, seasonal, and diurnal surface behavior of harbor porpoises
During ship surveys harbor porpoises are only visible when breaking the sea surface to breathe, while during aerial surveys they may be seen down to 2 m below the surface. The fractions of time spent at these two depths can be used for correcting visual surveys to actual population estimates, which...
Published in: | Marine Mammal Science |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2013
|
Subjects: | |
Online Access: | https://pure.au.dk/portal/en/publications/5fba5d62-9867-431e-8639-8a1d1e2df2eb https://doi.org/10.1111/j.1748-7692.2012.00597.x http://www.scopus.com/inward/record.url?scp=84875880652&partnerID=8YFLogxK |
id |
ftuniaarhuspubl:oai:pure.atira.dk:publications/5fba5d62-9867-431e-8639-8a1d1e2df2eb |
---|---|
record_format |
openpolar |
spelling |
ftuniaarhuspubl:oai:pure.atira.dk:publications/5fba5d62-9867-431e-8639-8a1d1e2df2eb 2024-02-11T10:07:58+01:00 Geographic, seasonal, and diurnal surface behavior of harbor porpoises Teilmann, Jonas Christiansen, Casper T. Kjellerup, Sanne Dietz, Rune Nachman, Gösta 2013-04-01 https://pure.au.dk/portal/en/publications/5fba5d62-9867-431e-8639-8a1d1e2df2eb https://doi.org/10.1111/j.1748-7692.2012.00597.x http://www.scopus.com/inward/record.url?scp=84875880652&partnerID=8YFLogxK eng eng https://pure.au.dk/portal/en/publications/5fba5d62-9867-431e-8639-8a1d1e2df2eb info:eu-repo/semantics/restrictedAccess Teilmann , J , Christiansen , C T , Kjellerup , S , Dietz , R & Nachman , G 2013 , ' Geographic, seasonal, and diurnal surface behavior of harbor porpoises ' , Marine Mammal Science , vol. 29 , no. 2 , pp. E60-E76 . https://doi.org/10.1111/j.1748-7692.2012.00597.x Aerial surveys Correction factor Diurnal surface pattern Diving behavior Geographical differences Line transect surveys Phocoena phocoena Satellite telemetry Ship surveys Surface time article 2013 ftuniaarhuspubl https://doi.org/10.1111/j.1748-7692.2012.00597.x 2024-01-17T23:59:05Z During ship surveys harbor porpoises are only visible when breaking the sea surface to breathe, while during aerial surveys they may be seen down to 2 m below the surface. The fractions of time spent at these two depths can be used for correcting visual surveys to actual population estimates, which are essential information on the status and management of the species. Thirty-five free-ranging harbor porpoises (Phocoena phocoena) were tracked in the region between the Baltic and the North Sea for 25-349 d using Argos satellite transmitters. No differences were found in surface behavior between geographical areas or the size of the animals. Slight differences were found between the two sexes and time of day. Surface time peaked in April, where 6% was spent with the transmitter above surface and 61.5% between 0 and 2 m depth, while the minimum values occurred in February (3.4% and 42.5%, respectively). The analyses reveal that individual variation among porpoises is the most important factor in explaining variation in surface rates. However, the large number of animals documented in the present study covering a wide range of age and sex groups justifies the use of the seasonal average surface times for correcting abundance surveys. Article in Journal/Newspaper Phocoena phocoena Aarhus University: Research Marine Mammal Science 29 2 E60 E76 |
institution |
Open Polar |
collection |
Aarhus University: Research |
op_collection_id |
ftuniaarhuspubl |
language |
English |
topic |
Aerial surveys Correction factor Diurnal surface pattern Diving behavior Geographical differences Line transect surveys Phocoena phocoena Satellite telemetry Ship surveys Surface time |
spellingShingle |
Aerial surveys Correction factor Diurnal surface pattern Diving behavior Geographical differences Line transect surveys Phocoena phocoena Satellite telemetry Ship surveys Surface time Teilmann, Jonas Christiansen, Casper T. Kjellerup, Sanne Dietz, Rune Nachman, Gösta Geographic, seasonal, and diurnal surface behavior of harbor porpoises |
topic_facet |
Aerial surveys Correction factor Diurnal surface pattern Diving behavior Geographical differences Line transect surveys Phocoena phocoena Satellite telemetry Ship surveys Surface time |
description |
During ship surveys harbor porpoises are only visible when breaking the sea surface to breathe, while during aerial surveys they may be seen down to 2 m below the surface. The fractions of time spent at these two depths can be used for correcting visual surveys to actual population estimates, which are essential information on the status and management of the species. Thirty-five free-ranging harbor porpoises (Phocoena phocoena) were tracked in the region between the Baltic and the North Sea for 25-349 d using Argos satellite transmitters. No differences were found in surface behavior between geographical areas or the size of the animals. Slight differences were found between the two sexes and time of day. Surface time peaked in April, where 6% was spent with the transmitter above surface and 61.5% between 0 and 2 m depth, while the minimum values occurred in February (3.4% and 42.5%, respectively). The analyses reveal that individual variation among porpoises is the most important factor in explaining variation in surface rates. However, the large number of animals documented in the present study covering a wide range of age and sex groups justifies the use of the seasonal average surface times for correcting abundance surveys. |
format |
Article in Journal/Newspaper |
author |
Teilmann, Jonas Christiansen, Casper T. Kjellerup, Sanne Dietz, Rune Nachman, Gösta |
author_facet |
Teilmann, Jonas Christiansen, Casper T. Kjellerup, Sanne Dietz, Rune Nachman, Gösta |
author_sort |
Teilmann, Jonas |
title |
Geographic, seasonal, and diurnal surface behavior of harbor porpoises |
title_short |
Geographic, seasonal, and diurnal surface behavior of harbor porpoises |
title_full |
Geographic, seasonal, and diurnal surface behavior of harbor porpoises |
title_fullStr |
Geographic, seasonal, and diurnal surface behavior of harbor porpoises |
title_full_unstemmed |
Geographic, seasonal, and diurnal surface behavior of harbor porpoises |
title_sort |
geographic, seasonal, and diurnal surface behavior of harbor porpoises |
publishDate |
2013 |
url |
https://pure.au.dk/portal/en/publications/5fba5d62-9867-431e-8639-8a1d1e2df2eb https://doi.org/10.1111/j.1748-7692.2012.00597.x http://www.scopus.com/inward/record.url?scp=84875880652&partnerID=8YFLogxK |
genre |
Phocoena phocoena |
genre_facet |
Phocoena phocoena |
op_source |
Teilmann , J , Christiansen , C T , Kjellerup , S , Dietz , R & Nachman , G 2013 , ' Geographic, seasonal, and diurnal surface behavior of harbor porpoises ' , Marine Mammal Science , vol. 29 , no. 2 , pp. E60-E76 . https://doi.org/10.1111/j.1748-7692.2012.00597.x |
op_relation |
https://pure.au.dk/portal/en/publications/5fba5d62-9867-431e-8639-8a1d1e2df2eb |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1111/j.1748-7692.2012.00597.x |
container_title |
Marine Mammal Science |
container_volume |
29 |
container_issue |
2 |
container_start_page |
E60 |
op_container_end_page |
E76 |
_version_ |
1790606843986313216 |