Harbour porpoise surveys in Rockabill to Dalkey Island SAC, 2021

Category: Environment
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In order to contribute to the Department Housing, Local Government & Heritage (DHLGH) site management and surveillance, visual monitoring of harbour porpoises was carried out in Rockabill to Dalkey Island SAC during the summer of 2021. This was the third dedicated line transect survey of harbour porpoises within this SAC which enabled ongoing trends in summer density estimates to be explored. The objectives of the survey in 2021 were to:

i) derive updated summer density and population estimates for harbour porpoises within the Rockabill to Dalkey Island SAC using robust sampling methods for small cetacean density/population estimation;

ii) estimate associated Coefficients of Variation and 95% Confidence Intervals

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Theme Environment
Date released 2022-12-01
Date updated 2023-12-07
Dataset conforms to these standards The INSPIRE Directive or INSPIRE lays down a general framework for a Spatial Data Infrastructure (SDI) for the purposes of European Community environmental policies and policies or activities which may have an impact on the environment.
Rights notes ['http://creativecommons.org/licenses/by/4.0/', 'Copyright Government of Ireland. This dataset was created by National Parks and Wildlife Service, Department of Housing, Local Government and Heritage. This copyright material is licensed for re-use under the Creative Commons Attribution 4.0 International licence. http://creativecommons.org/licenses/by/4.0/', 'otherRestrictions']
Update frequency Other
Language English
Geographic coverage in GeoJSON format {"type":"Polygon","coordinates":[[[-10.650444030762, 50.807923689449],[-10.650444030762, 55.993470564449], [-5.289115905762, 55.993470564449], [-5.289115905762, 50.807923689449], [-10.650444030762, 50.807923689449]]]}
Spatial Reference Systems (SRS) WGS 84 (EPSG:4326)
Vertical Extent {"verticalDomainName": "EPSG Projection 5731 - Malin Head height", "minVerticalExtent": "0", "maxVerticalExtent": "1014"}
Provenance information The route of the survey vessel were stored on Garmin handheld GPS. Map files from each survey were downloaded using Garmin MapSource® software and saved as a text file. These data were then used to create ArcView (Version 9) shape files of the survey effort points, tracks, and location of all sightings recorded during each survey. Maps of the study area and associated survey data were created in Irish Grid (TM65_Irish Grid) with ArcMap 10.2 while maps of the prescribed survey area, survey track-lines and coordinates were obtained from DHLGH. Data concerning transects, effort, sightings, abundance and density were stored in a single MS Access database, which was queried and processed via GIS to produce sighting distribution maps.
Period of time covered (begin) 2021-06-01
Period of time covered (end) 2021-11-15