Harbour porpoise surveys in Rocakbill to Dalkey Island SAC, 2016

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A visual survey of harbour porpoises (Phocoena phocoena) was carried out in the summer of 2016 within the Rockabill to Dalkey Island SAC, Co Dublin in order to derive local density and abundance estimates. Single platform line-transect surveys were carried out according to a standardised design on four days between June and September 2016. Surveys were conducted between the 7th June and 15th September 2016. Distance sampling was used to produce a detection function based on the observed distribution of harbour porpoise sightings. Abundance estimates were calculated using the day as the sample and the sighting as the observation: (i) for all survey days, (ii) stratified by sea state and (iii) for all surveys combined Surveys were carried out in favourable weather conditions (i.e., sea-state ≤2, with visibility of at least 6km) on all four survey days. A combined total of 506km of track-line was surveyed, which resulted in 152 distinct sightings totalling at least 246 individual harbour porpoises. The observed proportion of young porpoises (juveniles and calves combined) to adults was 9.8% and the proportion of calves to adults was 5.7%. No other cetacean species was recorded on any of the surveys, but a number of grey and harbour seals were sighted during on-effort periods.

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Dáta eisithe 2022-07-07
Dáta nuashonraithe 2023-11-20
Cloíonn an tacar sonraí leis na caighdeáin seo 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.
Nótaí Cearta {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}
Minicíocht Nuashonraithe Eile
Teanga English
Clúdach Geografach i bhformáid GeoJSON {"type":"Polygon","coordinates":[[[-10.650444030762, 50.807923689449],[-10.650444030762, 55.993470564449], [-5.289115905762, 55.993470564449], [-5.289115905762, 50.807923689449], [-10.650444030762, 50.807923689449]]]}
SRS WGS 84 (EPSG:4326)
Méid Ingearach {"verticalDomainName": "EPSG Projection 5731 - Malin Head height", "minVerticalExtent": "0", "maxVerticalExtent": "1014"}
Eolas Dualfhoinse During each transect the position of the survey vessel was tracked continuously through a GPS receiver connected to a laptop computer while survey effort including environmental conditions (sea-state, wind strength and direction, glare, etc.) were recorded every 15 minutes using LOGGER software (IFAW).
Tréimhse ama clúdaithe (tús) 2016-06-07
Tréimhse ama clúdaithe (deireadh) 2016-09-15