db06c590-4f6d-4a8a-9b8c-ce45204103c1 eng utf8 dataset dataset NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom polardatacentre@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact 2024-04-25 ISO 19115 Geographic Information - Metadata ISO 19115:2003(E) European Petroleum Survey Group (EPSG) Geodetic Parameter Registry 2008-11-12 publication European Petroleum Survey Group EPSGadministrator@iogp.org https://www.epsg-registry.org/ EPSG Geodetic Parameter Dataset The EPSG Geodetic Parameter Dataset is a structured dataset of Coordinate Reference Systems and Coordinate Transformations, accessible through this online registry. information publisher urn:ogc:def:crs:EPSG::3031 6.18.3 Fisheries acoustic data, whale and bird data from two transits from the Falkland Islands to Tristan da Cunha during March 2018 (RRS James Clark Ross) and March 2019 (RRS Discovery) 2024-04-25 creation 2024-04-25 revision 2024-04-25 publication 2024-04-25 released 1.0 https://doi.org/10.5285/db06c590-4f6d-4a8a-9b8c-ce45204103c1 doi GB/NERC/BAS/PDC/01841 https://data.bas.ac.uk/ NE/R000107/1 award NE/T012439/1 award Please cite this item as: Morley, S.A, Campanella, F., Baylis, A.M.M., Barnes, D.K.A., Bell, J.B., Bennison, A., Collins, M.A., Glass, T., Martin, S.M., Whomersley, P., Young, E.F., & Schofield, A. (2024). Fisheries acoustic data, whale and bird data from two transits from the Falkland Islands to Tristan da Cunha during March 2018 (RRS James Clark Ross) and March 2019 (RRS Discovery) (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/db06c590-4f6d-4a8a-9b8c-ce45204103c1 The acoustic data is separated into different categories of plankton: fish, fish without swimbladders, gas bearing plankton, plankton, and total backscatter for the RRS James Clark Ross and RRS Discovery cruises. The data is for every nautical mile along the transit and separated into 19 depth bands (in one set of files) or aggregated together (in another set of files). The whale and bird number of each species are reported for each day. These research cruises were co-funded through partnerships between the Foreign, Commonwealth and Development Office, through the Blue Belt program run by Cefas & MMO, and UKRI through the British Antarctic Survey (BAS) National Capability - Official Development Assistance program (NE/R000107/1 and NE/T012439/1). No credit. completed Morley, Simon A British Antarctic Survey Researcher author Campanella, Fabio Centre for Environment, Fisheries and Aquaculture Science Researcher author Baylis, Alastair MM South Atlantic Environmental Research Institute Researcher author Barnes, David KA British Antarctic Survey Researcher author Bell, James B Centre for Environment, Fisheries and Aquaculture Science Researcher author Bennison, Ashley British Antarctic Survey Researcher author Collins, Martin A British Antarctic Survey Researcher author Glass, Trevor Tristan da Cunha Government Researcher author Martin, Stephanie M British Antarctic Survey Researcher author Whomersley, Paul Centre for Environment, Fisheries and Aquaculture Science Researcher author Young, Emma F British Antarctic Survey Researcher author Schofield, Andy Royal Society for the Protection of Birds Researcher author NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact asNeeded completed EARTH SCIENCE > Oceans > Ocean Acoustics > Acoustic Scattering EARTH SCIENCE > Oceans > Marine Environment Monitoring theme Global Change Master Directory (GCMD) Science Keywords 2026-01-27 publication 23 Global Change Data Center, Science and Exploration Directorate, Goddard Space Flight Center (GSFC) National Aeronautics and Space Administration (NASA) Greenbelt MD United States of America https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords Global Change Master Directory (GCMD) Keywords The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. information publisher ENSO Pelagic ecosystem change Southwest Atlantic higher predators theme Falkland Islands South Atlantic Ocean Tristan da Cunha South Atlantic Ocean place Oceanographic geographical features theme GEMET - INSPIRE themes, version 1.0 2021-01-06 revision otherRestrictions no limitations to public access otherRestrictions no limitations license Open Government Licence v3.0 otherRestrictions This data is governed by the NERC Data Policy: https://www.ukri.org/who-we-are/nerc/our-policies-and-standards/nerc-data-policy/ otherRestrictions This data is governed by the NERC data policy and supplied under Open Government Licence v.3 otherRestrictions No restrictions apply. url url crossReference url url crossReference doi doi crossReference textTable eng utf8 biota environment oceans -57.60053 -7.98025 -51.64759 -38.18778 2018-03-15 2018-03-23 It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk. NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information distributor text/plain text/csv bytes 62914560 http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=db06c590-4f6d-4a8a-9b8c-ce45204103c1 WWW:LINK-1.0-http--link Get Data Download data download bytes 62914560 http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=db06c590-4f6d-4a8a-9b8c-ce45204103c1 WWW:LINK-1.0-http--link Get Data Download data download dataset Methodology: Underway acoustics Multifrequency acoustic data were collected using a hull-mounted Simrad EK60 echosounder (18, 38, 70, 120, 200, and 333 kHz). The echosounders were calibrated using a 38.1 mm tungsten carbide sphere following the standard sphere method. The calibration performed on the RRS Discovery highlighted a malfunctioning of the 18 and 38 kHz transducers precluding the use of those frequencies. For this reason, the main frequency used for the analysis was 70 kHz (70 kHz was also used for the 2018 data for consistency). The settings and calibration parameters of the acoustic equipment used in the two expeditions are detailed in the associated manuscript. The acoustic data from the surface to a maximum depth of 600 m (below which the 70 kHz data were affected by absorption) were cleaned and processed using the software Echoview v10. The area immediately below the transducers (about 10 m below) was excluded from the analysis because it was affected by the near-field effect and surface noise (e.g., surface bubbles). Background noise, pulse noise and attenuated signals were removed using a series of tools integrated in the Echoview software. The Nautical Area Backscattering Coefficient (NASC) was exported from the 'clean' echograms and used for further analyses. NASC, also referred to as backscatter, was considered a proxy for relative biomass. The horizontal sampling unit used to export the NASC was 1 nm. In order to discriminate different classes of acoustic target, a combination of thresholding and the difference in mean volume backscattering strength (DB differencing) was also used. The analysis consisted of two steps: (i) Thresholding - Mean Volume Backscattering Strength (MVBS) at 70 and 120 kHz was summed and the resulting echogram was thresholded in order to separate two broad classes of targets (fish vs plankton). The difference in variability between fish and zooplankton was used to enhance the contrast between both types of organisms. The use of this approach is helpful when there is a high density of gas-bearing plankton that can easily be mistaken for fish if only dB-differencing is used. The threshold value used for the data collected during the day was empirically chosen at -140 dB. Values above the threshold were classified as fish and values below the threshold were identified as plankton. A Boolean mask was then used to assign the backscatter to fish and plankton; (ii) DB differencing - the fish and plankton categories were further separated into four additional classes (fish with swimbladder, fish without swimbladder, fluid-like plankton, gas-bearing plankton). Identification of these classes was based on the differences of MVBS measured at 120 and 70 kHz (delta MVBS120-70). The NASC for the 'fish' and 'gas-bearing' plankton categories was exported at 70 kHz using a minimum Sv (Volume backscattering strength, dB re 1 m-1) threshold value of -70 dB. The NASC for the 'fish without swimbladder' and 'fluid-like plankton' categories was exported at 120 kHz using a minimum Sv (Volume backscattering strength, dB re 1 m-1) threshold value of -85 dB. The spatial patterns of distribution of the different scatter categories were investigated using a set of spatial metrics calculated in a cell of 1 nm (horizontally) by 200 m (vertically). Specifically, we estimated center of gravity, equivalent area and inertia. The center of mass is the mean location of the backscatter in the water column; the inertia is a measure of the dispersion of the backscatter around its center of gravity; the equivalent area is an individual-based index of the area occupied by the backscatter and it is a measure of the evenness. The spatial metrics were estimated using the daytime data only to exclude the effects of vertical migrations within the water column. The spatial metrics and the NASC were grouped in 5 degree longitudinal classes an...(20) Data collection: For fisheries acoustics: Hull-mounted Simrad EK60 echosounder (18, 38, 70, 120, 200, and 333 kHz). asNeeded completed