Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea
Harbour porpoise Phocoena phocoena is the only cetacean species resident in the Baltic Sea. At least 2 different subpopulations occur in this area, with a presumed demarcation line in the western Baltic Sea. Aerial surveys were conducted during different seasons in the years 2002 to 2006, to obtain...
Published in: | Endangered Species Research |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2008
|
Subjects: | |
Online Access: | https://research.wur.nl/en/publications/harbour-porpoise-phocoena-phocoena-abundance-in-the-southwestern- https://doi.org/10.3354/esr00161 |
id |
ftunivwagenin:oai:library.wur.nl:wurpubs/374457 |
---|---|
record_format |
openpolar |
spelling |
ftunivwagenin:oai:library.wur.nl:wurpubs/374457 2024-02-04T10:01:00+01:00 Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea Scheidat, M. Gilles, A. Kock, K.H. Siebert, U. 2008 application/pdf https://research.wur.nl/en/publications/harbour-porpoise-phocoena-phocoena-abundance-in-the-southwestern- https://doi.org/10.3354/esr00161 en eng https://edepot.wur.nl/42789 https://research.wur.nl/en/publications/harbour-porpoise-phocoena-phocoena-abundance-in-the-southwestern- doi:10.3354/esr00161 info:eu-repo/semantics/openAccess Wageningen University & Research Endangered Species Research 5 (2008) ISSN: 1863-5407 Abundance Aerial survey Baltic Sea Bycatch Distribution Harbour porpoise info:eu-repo/semantics/article Article/Letter to editor info:eu-repo/semantics/publishedVersion 2008 ftunivwagenin https://doi.org/10.3354/esr00161 2024-01-10T23:24:18Z Harbour porpoise Phocoena phocoena is the only cetacean species resident in the Baltic Sea. At least 2 different subpopulations occur in this area, with a presumed demarcation line in the western Baltic Sea. Aerial surveys were conducted during different seasons in the years 2002 to 2006, to obtain estimates of porpoise abundance for the southwestern Baltic. Within the survey area, 3 strata were defined. In total, 46 surveys were completed for these strata. Abundance estimates and corresponding confidence intervals (CI) were calculated for each stratum separately for each survey. Density between areas varied seasonally and spatially, with the western study area (Kiel Bight) generally showing the highest density. Whenever all 3 strata were covered within 25 consecutive days, abundance for the overall survey area was calculated. Ten surveys met these criteria. Overall abundance in the western Baltic varied between surveys, with the lowest value in March 2003 (457 ind.; 95% CI: 0 to 1632), and the highest estimate in May 2005 (4610 ind.; 95% CI: 2259 to 9098). The results of all other surveys were in the range from 1352 to 2905 ind., with largely overlapping confidence intervals. Applying the only available bycatch estimates (which include no measure of precision) currently available for the German Baltic region, the percent of porpoise bycatch in the western Baltic lies within a range of 1.78 to 17.94% of the local population. To increase the precision of bycatch rates, more detailed bycatch estimates for this region are needed. Nevertheless, the results indicate that bycatch is a major threat to harbour porpoises throughout the western Baltic Sea. Article in Journal/Newspaper Harbour porpoise Phocoena phocoena Wageningen UR (University & Research Centre): Digital Library Endangered Species Research 5 215 223 |
institution |
Open Polar |
collection |
Wageningen UR (University & Research Centre): Digital Library |
op_collection_id |
ftunivwagenin |
language |
English |
topic |
Abundance Aerial survey Baltic Sea Bycatch Distribution Harbour porpoise |
spellingShingle |
Abundance Aerial survey Baltic Sea Bycatch Distribution Harbour porpoise Scheidat, M. Gilles, A. Kock, K.H. Siebert, U. Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea |
topic_facet |
Abundance Aerial survey Baltic Sea Bycatch Distribution Harbour porpoise |
description |
Harbour porpoise Phocoena phocoena is the only cetacean species resident in the Baltic Sea. At least 2 different subpopulations occur in this area, with a presumed demarcation line in the western Baltic Sea. Aerial surveys were conducted during different seasons in the years 2002 to 2006, to obtain estimates of porpoise abundance for the southwestern Baltic. Within the survey area, 3 strata were defined. In total, 46 surveys were completed for these strata. Abundance estimates and corresponding confidence intervals (CI) were calculated for each stratum separately for each survey. Density between areas varied seasonally and spatially, with the western study area (Kiel Bight) generally showing the highest density. Whenever all 3 strata were covered within 25 consecutive days, abundance for the overall survey area was calculated. Ten surveys met these criteria. Overall abundance in the western Baltic varied between surveys, with the lowest value in March 2003 (457 ind.; 95% CI: 0 to 1632), and the highest estimate in May 2005 (4610 ind.; 95% CI: 2259 to 9098). The results of all other surveys were in the range from 1352 to 2905 ind., with largely overlapping confidence intervals. Applying the only available bycatch estimates (which include no measure of precision) currently available for the German Baltic region, the percent of porpoise bycatch in the western Baltic lies within a range of 1.78 to 17.94% of the local population. To increase the precision of bycatch rates, more detailed bycatch estimates for this region are needed. Nevertheless, the results indicate that bycatch is a major threat to harbour porpoises throughout the western Baltic Sea. |
format |
Article in Journal/Newspaper |
author |
Scheidat, M. Gilles, A. Kock, K.H. Siebert, U. |
author_facet |
Scheidat, M. Gilles, A. Kock, K.H. Siebert, U. |
author_sort |
Scheidat, M. |
title |
Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea |
title_short |
Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea |
title_full |
Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea |
title_fullStr |
Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea |
title_full_unstemmed |
Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea |
title_sort |
harbour porpoise phocoena phocoena abundance in the southwestern baltic sea |
publishDate |
2008 |
url |
https://research.wur.nl/en/publications/harbour-porpoise-phocoena-phocoena-abundance-in-the-southwestern- https://doi.org/10.3354/esr00161 |
genre |
Harbour porpoise Phocoena phocoena |
genre_facet |
Harbour porpoise Phocoena phocoena |
op_source |
Endangered Species Research 5 (2008) ISSN: 1863-5407 |
op_relation |
https://edepot.wur.nl/42789 https://research.wur.nl/en/publications/harbour-porpoise-phocoena-phocoena-abundance-in-the-southwestern- doi:10.3354/esr00161 |
op_rights |
info:eu-repo/semantics/openAccess Wageningen University & Research |
op_doi |
https://doi.org/10.3354/esr00161 |
container_title |
Endangered Species Research |
container_volume |
5 |
container_start_page |
215 |
op_container_end_page |
223 |
_version_ |
1789966593196818432 |