1. Australian Antarctic Data Centre
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4. AAS_4512_TEMPO_bioacoustics

Description

This data may be used to reproduce the analyses (including figures and tables), of 'Two scales of distribution and biomass of Antarctic krill (Euphausia superba) in the eastern sector of the CCAMLR Division 58.4.2 (55°E to 80°E)'.

The data describe krill biomass density distribution and krill net samples (krill total length and krill wetmass) collected during the 2021 TEMPO voyage on R/V Investigator.

During the TEMPO voyage krill biomass was estimated using observations from two sampling instruments: a calibrated EK80 scientific echosounder operating at 120 kHz and an rectangular midwater trawl (RMT 1+8). The supporting data sets, all in CSV format, are split by instrument type.

The EK80 has two datafiles:

1. krill_density.csv – krill areal density from the TEMPO transects, and
2. krill_swarms.csv -krill swarms detected during the TEMPO transects.

The RMT1+8 has four datafiles

1. net_locations.csv
2. krill_lengths.csv
3. krill_wet_mass_to_length.csv
4. krill_wet_mass_to_length_model_predictions.csv

The fields (columns) in each data file are:

krill_density.csv
"lat_M" – centre latitude of an echo integration interval [degrees] (dd.ddddd) WGS84 spheroid (GPS latitude)
"lon_M" - centre longitude of an echo integration interval [degrees] (dd.ddddd) WGS84 spheroid (GPS longitude),
"areal_biomass_density_g_per_m2" – Echo integration interval krill areal biomass density [g wet-mass / m^2]
"daynight" – flag for when the sampling took place [day/night]
"survey" – Either the main survey for the TEMPO biomass survey or the smaller-scale ‘Mawson box’ survey

krill_swarms.csv
"transect" – transect number
"lat" – latitude [degrees] (dd.ddddd) WGS84 spheroid (GPS latitude)
"swarm_depth_m" – mean depth of a krill swarm [m]
"daynight" – flag for when the sampling took place [day/night]
”volumetric_density_g_per_m3" – krill swarm internal volumetric biomass density [g wet-mass / m^3]

net_locations.csv
"station" – Station name for net trawl R for routine haul, T for target trawl
"lat" – mean latitude of a net trawl [degrees] (dd.ddddd) WGS84 spheroid (GPS latitude)
"lon" – mean longitude of a net trawl [degrees] (dd.ddddd) WGS84 spheroid (GPS longitude)
"daynight" – flag for when the sampling took place [day/night]

krill_lengths.csv
"station" – Station name for net trawl R for routine haul, T for target trawl
"total_length_mm” – total length of an individual krill [mm]

krill_wet_mass_to_length.csv
"total_length_mm" – total length of an individual krill [mm]
"wet_mass_g" - wet-mass an individual krill [g]

krill_wet_mass_to_length_model_predictions.csv
"total_length_mm" - total length of an individual krill [mm]
"predicted_wet_mass_g" – predicted mean wet-mass an individual krill of length ("total_length_mm" ) [g]
"LB_wet_mass_g" – Lower bound (lower 95% confidence interval) for the predicted_wet_mass_g [g]
"UB_wet_mass_g"– Upper bound (upper 95% confidence interval) for the predicted_wet_mass_g [g]

Purpose

The purpose of these data are three fold:

1. Enable the estimation of krill biomass in the eastern sector of the CCAMLR Division 58.4.2 (55°E to 80°E);
2. Access how representative krill observed in a small-scale survey to krill seen at larger scales, and
3. Support the publication of the accompanying paper.

Access

These data are publicly available for download from the provided URL.

Temporal Coverages

• Start date: 2021-02-13 - Stop date: 2021-03-11

Spatial Coverages

Data Resolution

Science Keywords

• EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES > ARTHROPODS > CRUSTACEANS
• EARTH SCIENCE > OCEANS > OCEAN ACOUSTICS > ACOUSTIC FREQUENCY
• EARTH SCIENCE > OCEANS > OCEAN ACOUSTICS > ACOUSTIC SCATTERING

Use Constraints

This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/).

Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAS_4512_TEMPO_bioacoustics when using these data.