Data from: Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises
1. Robust estimates of the density or abundance of cetaceans are required to support a wide range of ecological studies and inform management decisions. Considerable effort has been put into the development of line-transect sampling techniques to obtain estimates of absolute density from aerial and...
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Data Archiving and Networked Services (DANS)
2017
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Online Access: | https://doi.org/10.5061/dryad.cf04g |
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fttriple:oai:gotriple.eu:50|dedup_wf_001::682eb2ad3bfeca54e747e3774a3e9b4f 2023-05-15T16:33:21+02:00 Data from: Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises Williamson, Laura D. Brookes, Kate L. Scott, Beth E. Graham, Isla M. Bradbury, Gareth Hammond, Philip S. Thompson, Paul M. 2017-01-01 https://doi.org/10.5061/dryad.cf04g undefined unknown Data Archiving and Networked Services (DANS) http://dx.doi.org/10.5061/dryad.cf04g https://dx.doi.org/10.5061/dryad.cf04g lic_creative-commons oai:easy.dans.knaw.nl:easy-dataset:92318 10.5061/dryad.cf04g oai:services.nod.dans.knaw.nl:Products/dans:oai:easy.dans.knaw.nl:easy-dataset:92318 10|re3data_____::84e123776089ce3c7a33db98d9cd15a8 10|openaire____::9e3be59865b2c1c335d32dae2fe7b254 re3data_____::r3d100000044 10|re3data_____::94816e6421eeb072e7742ce6a9decc5f 10|eurocrisdris::fe4903425d9040f680d8610d9079ea14 10|openaire____::081b82f96300b6a6e3d282bad31cb6e2 Life sciences medicine and health care Density Surface Modelling Acoustics abundance distance sampling digital survey availability Harbour Porpoise North Sea Phocoena phocoena geo envir Dataset https://vocabularies.coar-repositories.org/resource_types/c_ddb1/ 2017 fttriple https://doi.org/10.5061/dryad.cf04g 2023-01-22T17:23:17Z 1. Robust estimates of the density or abundance of cetaceans are required to support a wide range of ecological studies and inform management decisions. Considerable effort has been put into the development of line-transect sampling techniques to obtain estimates of absolute density from aerial and boat-based visual surveys. Surveys of cetaceans using acoustic loggers or digital cameras provide alternative methods to estimate relative density that have the potential to reduce cost and provide a verifiable record of all detections. However the ability of these methods to provide reliable estimates of relative density has yet to be established. 2. These methodologies were compared by conducting aerial visual line-transect surveys (n=10 days) and digital video strip-transect surveys (n=4 days) in the Moray Firth, Scotland. Simultaneous acoustic data were collected from moored echolocation detectors (C-PODs) at 58 locations across the study site. Density surface modelling (DSM) of visual survey data was used to estimate spatial variation in relative harbour porpoise density on a 4x4 km grid. DSM was also performed on the digital survey data, and the resulting model output compared to that from visual survey data. Estimates of relative density from visual surveys around acoustic monitoring sites were compared with several metrics previously used to characterise variation in acoustic detections of echolocation clicks. 3. There was a strong correlation between estimates of relative density from visual surveys and digital video surveys (Spearman's ρ=0.85). A correction to account for animals missed on the transect line (previously calculated for visual aerial surveys of harbour porpoise in the North Sea (Hammond et al. 2013)) was used to convert relative density from the visual surveys to absolute density. This allowed calculation of the first estimate of a proxy for detection probability in digital video surveys, suggesting that 61% (CV=0.53) of harbour porpoises were detected. There was also a strong correlation ... Dataset Harbour porpoise Phocoena phocoena Unknown |
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Open Polar |
collection |
Unknown |
op_collection_id |
fttriple |
language |
unknown |
topic |
Life sciences medicine and health care Density Surface Modelling Acoustics abundance distance sampling digital survey availability Harbour Porpoise North Sea Phocoena phocoena geo envir |
spellingShingle |
Life sciences medicine and health care Density Surface Modelling Acoustics abundance distance sampling digital survey availability Harbour Porpoise North Sea Phocoena phocoena geo envir Williamson, Laura D. Brookes, Kate L. Scott, Beth E. Graham, Isla M. Bradbury, Gareth Hammond, Philip S. Thompson, Paul M. Data from: Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises |
topic_facet |
Life sciences medicine and health care Density Surface Modelling Acoustics abundance distance sampling digital survey availability Harbour Porpoise North Sea Phocoena phocoena geo envir |
description |
1. Robust estimates of the density or abundance of cetaceans are required to support a wide range of ecological studies and inform management decisions. Considerable effort has been put into the development of line-transect sampling techniques to obtain estimates of absolute density from aerial and boat-based visual surveys. Surveys of cetaceans using acoustic loggers or digital cameras provide alternative methods to estimate relative density that have the potential to reduce cost and provide a verifiable record of all detections. However the ability of these methods to provide reliable estimates of relative density has yet to be established. 2. These methodologies were compared by conducting aerial visual line-transect surveys (n=10 days) and digital video strip-transect surveys (n=4 days) in the Moray Firth, Scotland. Simultaneous acoustic data were collected from moored echolocation detectors (C-PODs) at 58 locations across the study site. Density surface modelling (DSM) of visual survey data was used to estimate spatial variation in relative harbour porpoise density on a 4x4 km grid. DSM was also performed on the digital survey data, and the resulting model output compared to that from visual survey data. Estimates of relative density from visual surveys around acoustic monitoring sites were compared with several metrics previously used to characterise variation in acoustic detections of echolocation clicks. 3. There was a strong correlation between estimates of relative density from visual surveys and digital video surveys (Spearman's ρ=0.85). A correction to account for animals missed on the transect line (previously calculated for visual aerial surveys of harbour porpoise in the North Sea (Hammond et al. 2013)) was used to convert relative density from the visual surveys to absolute density. This allowed calculation of the first estimate of a proxy for detection probability in digital video surveys, suggesting that 61% (CV=0.53) of harbour porpoises were detected. There was also a strong correlation ... |
format |
Dataset |
author |
Williamson, Laura D. Brookes, Kate L. Scott, Beth E. Graham, Isla M. Bradbury, Gareth Hammond, Philip S. Thompson, Paul M. |
author_facet |
Williamson, Laura D. Brookes, Kate L. Scott, Beth E. Graham, Isla M. Bradbury, Gareth Hammond, Philip S. Thompson, Paul M. |
author_sort |
Williamson, Laura D. |
title |
Data from: Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises |
title_short |
Data from: Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises |
title_full |
Data from: Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises |
title_fullStr |
Data from: Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises |
title_full_unstemmed |
Data from: Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises |
title_sort |
data from: echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises |
publisher |
Data Archiving and Networked Services (DANS) |
publishDate |
2017 |
url |
https://doi.org/10.5061/dryad.cf04g |
genre |
Harbour porpoise Phocoena phocoena |
genre_facet |
Harbour porpoise Phocoena phocoena |
op_source |
oai:easy.dans.knaw.nl:easy-dataset:92318 10.5061/dryad.cf04g oai:services.nod.dans.knaw.nl:Products/dans:oai:easy.dans.knaw.nl:easy-dataset:92318 10|re3data_____::84e123776089ce3c7a33db98d9cd15a8 10|openaire____::9e3be59865b2c1c335d32dae2fe7b254 re3data_____::r3d100000044 10|re3data_____::94816e6421eeb072e7742ce6a9decc5f 10|eurocrisdris::fe4903425d9040f680d8610d9079ea14 10|openaire____::081b82f96300b6a6e3d282bad31cb6e2 |
op_relation |
http://dx.doi.org/10.5061/dryad.cf04g https://dx.doi.org/10.5061/dryad.cf04g |
op_rights |
lic_creative-commons |
op_doi |
https://doi.org/10.5061/dryad.cf04g |
_version_ |
1766023047553220608 |