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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ftzenodo:oai:zenodo.org:4998411 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. 2017-01-15 https://zenodo.org/record/4998411 https://doi.org/10.5061/dryad.cf04g unknown doi:10.1111/2041-210X.12538 https://zenodo.org/communities/dryad https://zenodo.org/record/4998411 https://doi.org/10.5061/dryad.cf04g oai:zenodo.org:4998411 info:eu-repo/semantics/openAccess https://creativecommons.org/publicdomain/zero/1.0/legalcode distance sampling digital survey Density Surface Modelling Phocoena phocoena acoustics availability Harbour Porpoise info:eu-repo/semantics/other dataset 2017 ftzenodo https://doi.org/10.5061/dryad.cf04g10.1111/2041-210X.12538 2023-03-10T15:11:34Z 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 Zenodo |
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Open Polar |
collection |
Zenodo |
op_collection_id |
ftzenodo |
language |
unknown |
topic |
distance sampling digital survey Density Surface Modelling Phocoena phocoena acoustics availability Harbour Porpoise |
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distance sampling digital survey Density Surface Modelling Phocoena phocoena acoustics availability Harbour Porpoise 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 |
distance sampling digital survey Density Surface Modelling Phocoena phocoena acoustics availability Harbour Porpoise |
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 |
publishDate |
2017 |
url |
https://zenodo.org/record/4998411 https://doi.org/10.5061/dryad.cf04g |
genre |
Harbour porpoise Phocoena phocoena |
genre_facet |
Harbour porpoise Phocoena phocoena |
op_relation |
doi:10.1111/2041-210X.12538 https://zenodo.org/communities/dryad https://zenodo.org/record/4998411 https://doi.org/10.5061/dryad.cf04g oai:zenodo.org:4998411 |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/publicdomain/zero/1.0/legalcode |
op_doi |
https://doi.org/10.5061/dryad.cf04g10.1111/2041-210X.12538 |
_version_ |
1766023048421441536 |