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Acoustic backscatter data and RMT25 abundance and biomass data for Scotia Sea, Southern Ocean 2006, 2008, 2009, 2015, 2016 and 2017
This is a mixed data set held in six excel files, containing processed acoustic backscatter data, mesopelagic fish abundance and swimbladder contents from night time sampled RMT25 nets, plus net catch data for all fauna combined and dominant mesopelagic fish in night time RMT25.
Acoustic backscatter data is from 6 latitudinal acoustic transects spanning the Scotia Sea, obtained during cruises JR161, JR177, JR200, JR15002 and JR15004 (two transects). Data were collected using a Simrad EK60 echo sounder at 38 kHz. The EK60 was run continuously between Stanley (Falkland Islands) and Signy (South Orkney Islands). Fish data was collected using RMT25 night time net samples from 5 cruises JR161, JR177, JR200, JR15004 and JR16003. The data set focuses on 11 species of mesopelagic fish Bathylagus species, Cyclothone species, Electrona antarctica, Electrona carlsbergi, Gymnoscopelus braueri, Gymnoscopelus fraseri, Gymnoscopelus nicholsi, Krefftichthys anderssoni, Protomyctophum bolini, Protomyctophum tenisoni and Notolepis species. Abundance and proportion data was obtained for combined fish species, and identified by net tow and latitude. Biomass for all fauna and the 11 fish species was calculated from RMT25 night catch log data. Myctophid gas presence absence was determined from a combination of dissection, Computed Tomography and soft tissue X-ray.
Funding was provided by the NERC grants NE/L002434/1 and bas010017.
This data is embargoed until August 2019.
Simple
- Date (Creation)
- 2019-04-15
- Date (Revision)
- 2019-04-15
- Date (Publication)
- 2019-04-15
- Date (released)
- 2019-04-15
- Edition
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1.0
- Unique resource identifier
- https://doi.org/10.5285/e15d622c-5c7e-45e9-b127-f27def94bbe8
- Codespace
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doi
- Unique resource identifier
- GB/NERC/BAS/PDC/01142
- Codespace
- Unique resource identifier
- NE/L002434/1
- Codespace
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award
- Other citation details
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Please cite this item as: Dornan, T., Fielding, S., Saunders, R., & Stowasser, G. (2019). Acoustic backscatter data and RMT25 abundance and biomass data for Scotia Sea, Southern Ocean 2006, 2008, 2009, 2015, 2016 and 2017 (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/e15d622c-5c7e-45e9-b127-f27def94bbe8
- Credit
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No credit.
- Status
- Completed
- Point of contact
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Organisation name Individual name Electronic mail address Role British Antarctic Survey, Natural Environment Research Council, UK Research & Innovation Dornan, Tracey Author University of Bristol
Dornan, Tracey Author British Antarctic Survey, Natural Environment Research Council, UK Research & Innovation Fielding, Sophie Author British Antarctic Survey, Natural Environment Research Council, UK Research & Innovation Saunders, Ryan
Author British Antarctic Survey, Natural Environment Research Council, UK Research & Innovation Stowasser, Gabriele Author NERC EDS UK Polar Data Centre Point of contact
- Maintenance and update frequency
- As needed
- Maintenance note
- Completed
- Theme
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Abundance
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Acoustic backscatter
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Biomass
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Mesopelagic fish
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Myctophid
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Swimbladder
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- Place
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Scotia Sea Southern Ocean
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South Orkney Islands Southern Ocean
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South Georgia Southern Ocean
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GEMET - INSPIRE themes, version 1.0
- Access constraints
- Other restrictions
- Other constraints
- no limitations to public access
- Access constraints
- Other restrictions
- Other constraints
- no limitations
- Use constraints
- License
- Other constraints
- Open Government Licence v3.0
- Use constraints
- Other restrictions
- Other constraints
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Data released under Open Government Licence V3.0:
- Use constraints
- Other restrictions
- Other constraints
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No restrictions apply.
- Unique resource identifier
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url
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url
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doi
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doi
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doi
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- Cross reference
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url
- Association Type
- Cross reference
- Spatial representation type
- Text, table
- Language
- English
- Character set
- UTF8
- Topic category
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- Biota
- Environment
- Oceans
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- Begin date
- 2006-10-25
- End date
- 2016-02-20
- Supplemental Information
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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.
- Title
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European Petroleum Survey Group (EPSG) Geodetic Parameter Registry
- Date (Publication)
- 2008-11-12
- Cited responsible party
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Organisation name Individual name Electronic mail address Role European Petroleum Survey Group
Publisher
- Unique resource identifier
- urn:ogc:def:crs:EPSG::3031
- Version
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6.18.3
Distributor
- Distributor contact
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Organisation name Individual name Electronic mail address Role NERC EDS UK Polar Data Centre Distributor
- Distributor format
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Name Version application/vnd.ms-excel
- Units of distribution
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bytes
- Transfer size
- 844800
- OnLine resource
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Protocol Linkage Name WWW:LINK-1.0-http--link
https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=e15d622c-5c7e-45e9-b127-f27def94bbe8 Get Data
- Hierarchy level
- Dataset
- Statement
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Methodology:
Detailed surveys for mesopelagic fish were conducted in the Scotia Sea as part of the British Antarctic Survey's Discovery 2010 programme, as described in Collins et al. (2012). Follow up investigations were carried out using the same methods during JR15004 and JR16003.
An opening and closing 25 m2 rectangular mid-water trawl net (RMT25) was deployed at locations spanning the Scotia Sea and major frontal positions from north of the Antarctic Polar Front (APF) to the sea ice zone (SIZ). Cruise timings: November 2006 (cruise JR161, Austral spring), January 2008 (cruise JR177, Austral summer), March 2009 (cruise JR200, Austral autumn), January-February 2016 (cruise JR15004, Austral summer), and January 2017 (cruise JR16003, Austral summer).
Stratified net hauls were carried that encompassed the main water masses and frontal zones of the region; Polar Front (PF), Southern Scotia Sea (SSS), Mid Scotia Sea (MSS), Western Scotia Sea (WSS), Northern Scotia Sea (NSS), and Georgia Basin (GB), at depths of: 0-200, 200-400, 400-700, and 700-1000 m. Only night sampled net hauls are included in the data set and abundance and proportions restricted to those net samples where the entire water column was sampled.
All fish caught were sorted on-board, identified to the lowest taxonomic level, and measured to the nearest mm using standard length. Wet mass was recorded either for the entire catch or for each species using a motion-compensated balance. Where no wet weight was recorded for a species, this was estimated based on the mean wet mass for a species from the existing data from JR161, JR177 and JR200. Where neither wet mass nor abundance was recorded, the entire net was excluded from the data set.
Myctophid gas presence absence was compiled from a combination of dissection, Computed Tomography and soft tissue X-ray. The presence or absence of gas in Electrona antarctica in relation to fish length are also presented, these fish were sampled opportunistically from RMT25, RMT6 and MOCNESS net during the same cruises.
Data collection:
Acoustic Data collected using a Simrad EK60 echo sounder
Acoustic Data processed using Echoview version 8.0.95.32073
Analysis in R version 3.5.1
Data quality:
The acoustic data was calibrated, cleaned in Echoview to remove bad data regions, including false bottom echoes, seabed, surface near-field, intermittent noise and attenuated signal (all set to 'no-data'). Data was integrated in 1km distance by 10m depth cells. Further removal of data in water shallower than 1000m was carried out in R version 3.5.1 and the top 1% of high NASC values were manually scrutinised to check for any residual noise bias. Less than 10% of high NASC values were found to be attributable to noise and these were excluded from further analysis. Abundance data were only obtained from valid net hauls where the RMT25 device operated properly during deployment. Standard length measurements were obtained from all undamaged specimens during fieldwork. Abundance data for fish was compiled from the individual on board fish recording data, as length was required to differentiate between gas and non-gas bearing species (specifically for Electrona antarctica).
Biomass estimates are taken from on board catch weight data, where catch weight was recorded to the nearest gram for either total catch (JR15004 and JR16003), or total species catch (JR161, JR177, JR200, JR15004, JR16003). Total species catch for JR161, JR177 and JR200 was calculated by summing wet mass of all species for the catch. Where a catch weight was not recorded for a species, this was estimated by calculating the mean wet mass for each species from the existing combined JR161, JR177 and JR200, and multiplying the species abundance by the mean mass. Where neither wet mass nor abundance was recorded for a species the entire net was removed from the biomass assessment. All weight data were scrutinised for obvious erroneous values as result of measurement or typographic errors prior to compilation of this data set.
Metadata
- File identifier
- e15d622c-5c7e-45e9-b127-f27def94bbe8 XML
- Metadata language
- English
- Character set
- UTF8
- Hierarchy level
- Dataset
- Hierarchy level name
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dataset
- Date stamp
- 2019-04-15
- Metadata standard name
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ISO 19115 Geographic Information - Metadata
- Metadata standard version
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ISO 19115:2003(E)
- Metadata author
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Organisation name Individual name Electronic mail address Role NERC EDS UK Polar Data Centre Point of contact
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