9358b294bb61c7fab7216ec76975c00c English series ABP Marine Environmental Research Ltd Data Manager enquiries@abpmer.co.uk pointOfContact 2024-03-11 MEDIN Discovery metadata standard 2.3.8 urn:ogc:def:crs:EPSG::4326 2023, APEM, POSEIDON, Celtic Sea Seabird and Marine Mammal Surveys 2024-03-08 publication 2024-01-26 creation 2023-12-12 revision MDE-TCE-100-3789 This series includes the reporting and data deliverables for four year one seasonal aerial surveys of seabirds and marine mammals under the POSEIDON project. POSEIDON is a multi-year, multi-partner project funded through The Crown Estate OWEC programme and led by Natural England. The series constitutes: First seasonal (October to December 2022) report outlining results from digital aerial surveys conducted in January 2023 within the South-West Celtic Sea under the POSEIDON project and commissioned by Natural England. Surveys were undertaken using APEMs high-resolution camera system to capture digital still imagery of birds and marine megafauna within the Survey Area. The survey was successfully carried out in in a single day in January 2023, with no technical or safety issues. Due to weather delays, it was not possible to carry out the survey by the end of December 2022. A total of 746 observations were recorded in January 2023, of which 658 were observations of birds and 88 observations of marine megafauna. Second seasonal (January to March 2023) report outlining results from digital aerial surveys conducted in March 2023 within the South-West Celtic Sea under the POSEIDON project and commissioned by Natural England. Surveys were undertaken using APEM’s high-resolution camera system to capture digital still imagery of birds and marine megafauna within the Survey Area. The survey was successfully carried out by two planes in a single day in March 2023, with no technical or safety issues. A total of 818 observations were recorded in March 2023, of which 374 were observations of birds and 444 observations of marine megafauna. Third seasonal (April to June 2023) report outlining results from digital aerial surveys conducted in June 2023 within the South-West Celtic Sea under the POSEIDON project and commissioned by Natural England. Surveys were undertaken using APEM’s high-resolution camera system to capture digital still imagery of birds and marine megafauna within the Survey Area. The survey was successfully carried out in in a single day in June 2023, with no technical or safety issues. A total of 926 observations were recorded in June 2023, of which 520 were observations of birds and 406 observations of marine megafauna. Fourth seasonal (July to September 2023) report outlining results from digital aerial surveys conducted in September 2023 within the South-West Celtic Sea under the POSEIDON project and commissioned by Natural England. Surveys were undertaken using APEM’s high-resolution camera system to capture digital still imagery of birds and marine megafauna within the Survey Area. The survey was successfully carried out across two days in September, with no technical or safety issues. A total of 993 observations were recorded in September 2023, of which 646 were observations of birds and 347 observations of marine megafauna. Gareth Myers-McCann APEM Limited Data Operations Team dot@apemltd.co.uk originator The Crown Estate +44 020 7851 5000 1 St James's Market London SW1Y 4AH enquiries@thecrownestate.co.uk custodian notPlanned Delimited Documents Geographic Information System Marine Environmental Data and Information Network Species distribution GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Bird counts Cetacean behaviour Cetacean abundance Seal abundance Bird behaviour SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision Research Research and Development Activity otherRestrictions Publicly Available https://www.marinedataexchange.co.uk/content/info/terms-of-use 0.015 eng biota Charting Progress 2 Sea Areas 2009-06-18 creation Western Channel and Celtic Sea International Hydrographic Bureau, Limits of Oceans and Seas 1954-01-01 creation Celtic Sea SeaDataNet vertical extent keywords 2010-01-01 revision atmosphere -9.0000 -9.4500 48.5000 49.5000 -9.3600 -10.3700 48.1200 48.5600 -10.3700 -10.8300 47.4600 48.1800 2023-01-26 2023-09-03 https://www.marinedataexchange.co.uk/details/TCE-3789/summary A link to the web service or dataset. https://www.marinedataexchange.co.uk A link to the general host site. series MEDIN data guideline for video surveys of species and benthos 2023-05-11 publication See the referenced specification true The survey was conducted using APEMs bespoke camera system, customised by in-house specialists for surveying the offshore environment. The camera system is integrated with custom flight planning software that allows each survey flight line to be accurately mapped before the aircraft leaves the ground. Each image capture node is precisely defined, allowing the system to fire the camera exposures at exactly the right location. This ensures that each survey is flown with the same orientation and the camera is triggered at the same position within set tolerances. APEMs flight planning software enables tolerances along survey lines to be set, meaning the camera system would automatically abort data capture should the aircraft drift away from the planned flight line. APEMs on-board camera technician continually monitored the imagery as it was collected to ensure data collected was fit for purpose. The camera technician would make the decision to cease data collection should conditions become unsuitable for surveying or data collection. Subsequently, the survey would then be resumed at the next earliest opportunity. All completed surveys therefore maintained conditions conducive to successful surveying. Favourable conditions for surveying were defined as: a cloud base (lowest altitude of the visible portion of the cloud) of at least 1,300 ft, according to a geoidal model, to ensure there is no cloud below the planned altitude of the aircraft, visibility of greater than 5 km, wind speed of less than 30 knots, and sea state of 4 (moderate) or less. Naturally, the cloud base may vary in altitude, but aircraft will always fly lower than the lowest cloud level, if cloud base is lower than the planned aircraft altitude the survey would not take place. APEMs flight planning software allows for sideways, up and down movement of the aircraft to set tolerances ensuring the aircraft does not drift away from the line, and altitude remains suitable to achieve the required GSD. Whilst the image footprint and GSD both increase with altitude, the focus of the camera lenses ensures no discernible differences within the range of altitudes potentially flown. Wind speed was recorded at the same altitude as the aircraft, whereas sea state was determined from the appearance of the sea surface recorded by the onboard aerial survey technician. The two measures therefore do not necessarily correlate. For safety reasons, no surveying can take place in icing conditions. Data capture comprised digital still images of an average 1.5 cm GSD. Images at each camera are processed at each node, resulting in slight variation in GSD across the swath width. GSD is smaller than 1.5 cm GSD at the nadir and increases with distance from the nadir, resulting in an average GSD of 1.5 cm. Images were collected in a continuous transect-based design using a Global Positioning System (GPS) linked, bespoke flight management system to ensure the tracks were flown with a high degree of accuracy. The aircrafts internal GPS and Inertial Motion Unit (IMU) systems record to an accuracy of +/- 3 to 5 m as standard. The camera system captured abutting imagery along 11 survey flight lines spaced approximately 2 km apart within the Survey Area. The total Survey Area was 18,011 km2. The aircraft collected the data at an altitude of approximately 1,450 ft (440m) according to the ellipsoid model as recorded by GPS, equivalent to 1,300 ft (395 m) above geoidal mean sea level, and at a speed of approximately 120 knots. Images were collected continuously along the survey flight lines with slight overlap between image nodes. For analysis purposes each transect should be treated as a single sample, therefore for the current survey design, n=11. Total coverage was calculated to be 3.29% captured and 3.29% analysed, generated from 6,285 image nodes. A total of 18 nodes were not captured across lines 2, 3, 4 and 8. Impact on coverage was negligible, with the target of 3% coverage achieved, including a redundancy of an additional 0.29%, which is almost 10% contingency with respect to the target coverage. Table 2Imagery was captured in raw format and post-processed to ensure optimal quality for the subsequent stage of image analysis, to extract information on marine fauna or other notable occurrences. When a survey was completed, data were checked to ensure the number of lines and the number of images collected was correct, and that the quality of the imagery was acceptable. Once image analysis was completed, further quality assurance (QA) processes took place. Whilst strong winds (close to the standard limit of 30 knots during which condition are considered favourable for surveys) were noted during some lines, they did not constitute a health and safety risk. Weather conditions during all surveys were conducive to collecting and analysing imagery for the purpose of providing data on the identification, distribution, and abundance of bird species and marine fauna within the Survey Area. Measures were taken to minimise glint and glare, such as avoiding surveying when the sun angle had the greatest potential to impact image quality. Furthermore, data collected provided coverage of 3.29%, thus exceeding the 3% coverage required, enabling sufficient coverage to be collected should images be affected by glint or glare.