Rectangular Midwater Trawls (RMT) for krill during BROKE-West
Routine Trawls were conducted approximately every second CTD station. The target trawls were conducted when an interesting trace was seen on the echo sounders. Regular Trawl At each regular trawl station a quantitative standard double oblique tow was conducted from the surface down to 200 m (or to w...
id |
ftands:oai:ands.org.au::684814 |
---|---|
record_format |
openpolar |
institution |
Open Polar |
collection |
Research Data Australia (Australian National Data Service - ANDS) |
op_collection_id |
ftands |
language |
unknown |
topic |
biota oceans ANIMALS/INVERTEBRATES EARTH SCIENCE BIOLOGICAL CLASSIFICATION CRUSTACEANS ARTHROPODS EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > MARINE ECOSYSTEMS > PELAGIC EUPHAUSIIDS (KRILL) RMT STATION RANDOM CTD TARGET REGULAR STANDARD TOW KRILL ZOOPLANKTON Conductivity Temperature and depth Rectangular Midwater Trawls TRAWL SHIPS AMD/AU CEOS AMD ACE/CRC OCEAN > SOUTHERN OCEAN CONTINENT > ANTARCTICA GEOGRAPHIC REGION > POLAR |
spellingShingle |
biota oceans ANIMALS/INVERTEBRATES EARTH SCIENCE BIOLOGICAL CLASSIFICATION CRUSTACEANS ARTHROPODS EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > MARINE ECOSYSTEMS > PELAGIC EUPHAUSIIDS (KRILL) RMT STATION RANDOM CTD TARGET REGULAR STANDARD TOW KRILL ZOOPLANKTON Conductivity Temperature and depth Rectangular Midwater Trawls TRAWL SHIPS AMD/AU CEOS AMD ACE/CRC OCEAN > SOUTHERN OCEAN CONTINENT > ANTARCTICA GEOGRAPHIC REGION > POLAR Rectangular Midwater Trawls (RMT) for krill during BROKE-West |
topic_facet |
biota oceans ANIMALS/INVERTEBRATES EARTH SCIENCE BIOLOGICAL CLASSIFICATION CRUSTACEANS ARTHROPODS EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > MARINE ECOSYSTEMS > PELAGIC EUPHAUSIIDS (KRILL) RMT STATION RANDOM CTD TARGET REGULAR STANDARD TOW KRILL ZOOPLANKTON Conductivity Temperature and depth Rectangular Midwater Trawls TRAWL SHIPS AMD/AU CEOS AMD ACE/CRC OCEAN > SOUTHERN OCEAN CONTINENT > ANTARCTICA GEOGRAPHIC REGION > POLAR |
description |
Routine Trawls were conducted approximately every second CTD station. The target trawls were conducted when an interesting trace was seen on the echo sounders. Regular Trawl At each regular trawl station a quantitative standard double oblique tow was conducted from the surface down to 200 m (or to within 10 m of the bottom at stations shallower than 200 m). Such a depth range is considered to be the best compromise between the time available for sampling and the likely vertical depth range of krill. During the hauls, ship speed was maintained at a constant 2.5 plus or minus 0.5 knots. Wire speed of 0.7 to 0.8 m/s during paying out and of 0.3 m/sec during hauling (approx. 0.5 m/s and 0.2 m/s respectively at vertical depth change rate). The net mouth angle is remarkably constant during hauling within the speed ranges given above. When the net reaches maximum depth, the winch was stopped for about 30 seconds to allow the net to stabilise before starting retrieval. When hauling, propeller thrust was turned off when the net reached a depth of 15 to 20 m; this was to minimise the effects of the propeller action on the net operation and avoids damage of the samples. Target Trawl Whenever interesting targets were seen on the echo-sounder, or large amounts of krill were required for any purpose, target trawls were performed. Once the position of the target was marked, the ship was turned and navigated to run over the target from direction required within navigation capacity. The ship speed was lowered down to below 2.0 knots before hitting the target, so that the net could be lowered down to the desired depth whenever the net reached the target. Fine adjustments were made throughout the trawl by monitoring the echo-sounder in the aft control room. For live krill target trawl, ship speed was kept as slow as possible to avoid any damage to krill. Sample processing for all regular trawl stations: RMT-8 1.Measure the total sample volume (Drain water, then measure using water replacement; mandatory only for the regular hauls) 2.Sort out all Antarctic krill and count their number. If the sample mainly consists of krill and the volume is more than ~1L, a known portion of the whole sample was sub-sampled for the further processing. 3.Stage (TL, Carapace Length, Maturity) of all krill (or subsample), up to 50 to 150 individuals, and digestive gland size (the longest axis) of up to 50 individuals were measured using digital calipers. 4.Other zooplankton groups were immediately sorted out from the catch and their numbers were recorded. Preservation of RMT-8 samples Krill (including those used for onboard demography measurements) were fixed in 10% formalin for their further analysis. Whenever excess amount of krill catch were made, they were sampled and frozen for POP (persistent organic pollutant) measurements, preserved in 80% ethanol for genetic analysis, and frozen under -80C/ liquid nitrogen for chemical analysis. Fish were preserved in formalin, EtOH, or frozen. Squids were preserved in ethanol. RMT-1 1.The whole sample was fixed with 10 % formalin. 2.If the sample volume was too large, then a known proportion of catch was randomly sub-sampled and fixed. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679). |
author2 |
AADC (originator) AU/AADC > Australian Antarctic Data Centre, Australia (resourceProvider) |
format |
Dataset |
title |
Rectangular Midwater Trawls (RMT) for krill during BROKE-West |
title_short |
Rectangular Midwater Trawls (RMT) for krill during BROKE-West |
title_full |
Rectangular Midwater Trawls (RMT) for krill during BROKE-West |
title_fullStr |
Rectangular Midwater Trawls (RMT) for krill during BROKE-West |
title_full_unstemmed |
Rectangular Midwater Trawls (RMT) for krill during BROKE-West |
title_sort |
rectangular midwater trawls (rmt) for krill during broke-west |
publisher |
Australian Ocean Data Network |
url |
https://researchdata.ands.org.au/rectangular-midwater-trawls-broke-west/684814 https://data.aad.gov.au/metadata/records/BROKE-West_RMT_krill http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=4639 http://data.aad.gov.au/aadc/marine_science/catch/catch_list.cfm?set_code=200506030 http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=2084 https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2655 https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2679 http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=BROKE-West_RMT_krill |
op_coverage |
Spatial: northlimit=-61.67; southlimit=-69.21; westlimit=29.92; eastLimit=80.04 Temporal: From 2006-01-17 to 2006-02-28 |
long_lat |
ENVELOPE(29.92,80.04,-61.67,-69.21) |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Antarctic Krill Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Krill Antarctica Southern Ocean |
op_source |
https://data.aad.gov.au |
op_relation |
https://researchdata.ands.org.au/rectangular-midwater-trawls-broke-west/684814 d49dad2c-dc9c-4488-afed-1b5825e3ac6f https://data.aad.gov.au/metadata/records/BROKE-West_RMT_krill http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=4639 http://data.aad.gov.au/aadc/marine_science/catch/catch_list.cfm?set_code=200506030 http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=2084 https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2655 https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2679 http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=BROKE-West_RMT_krill |
_version_ |
1766245573167415296 |
spelling |
ftands:oai:ands.org.au::684814 2023-05-15T13:46:55+02:00 Rectangular Midwater Trawls (RMT) for krill during BROKE-West AADC (originator) AU/AADC > Australian Antarctic Data Centre, Australia (resourceProvider) Spatial: northlimit=-61.67; southlimit=-69.21; westlimit=29.92; eastLimit=80.04 Temporal: From 2006-01-17 to 2006-02-28 https://researchdata.ands.org.au/rectangular-midwater-trawls-broke-west/684814 https://data.aad.gov.au/metadata/records/BROKE-West_RMT_krill http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=4639 http://data.aad.gov.au/aadc/marine_science/catch/catch_list.cfm?set_code=200506030 http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=2084 https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2655 https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2679 http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=BROKE-West_RMT_krill unknown Australian Ocean Data Network https://researchdata.ands.org.au/rectangular-midwater-trawls-broke-west/684814 d49dad2c-dc9c-4488-afed-1b5825e3ac6f https://data.aad.gov.au/metadata/records/BROKE-West_RMT_krill http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=4639 http://data.aad.gov.au/aadc/marine_science/catch/catch_list.cfm?set_code=200506030 http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=2084 https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2655 https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2679 http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=BROKE-West_RMT_krill https://data.aad.gov.au biota oceans ANIMALS/INVERTEBRATES EARTH SCIENCE BIOLOGICAL CLASSIFICATION CRUSTACEANS ARTHROPODS EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > MARINE ECOSYSTEMS > PELAGIC EUPHAUSIIDS (KRILL) RMT STATION RANDOM CTD TARGET REGULAR STANDARD TOW KRILL ZOOPLANKTON Conductivity Temperature and depth Rectangular Midwater Trawls TRAWL SHIPS AMD/AU CEOS AMD ACE/CRC OCEAN > SOUTHERN OCEAN CONTINENT > ANTARCTICA GEOGRAPHIC REGION > POLAR dataset ftands 2020-01-05T21:05:40Z Routine Trawls were conducted approximately every second CTD station. The target trawls were conducted when an interesting trace was seen on the echo sounders. Regular Trawl At each regular trawl station a quantitative standard double oblique tow was conducted from the surface down to 200 m (or to within 10 m of the bottom at stations shallower than 200 m). Such a depth range is considered to be the best compromise between the time available for sampling and the likely vertical depth range of krill. During the hauls, ship speed was maintained at a constant 2.5 plus or minus 0.5 knots. Wire speed of 0.7 to 0.8 m/s during paying out and of 0.3 m/sec during hauling (approx. 0.5 m/s and 0.2 m/s respectively at vertical depth change rate). The net mouth angle is remarkably constant during hauling within the speed ranges given above. When the net reaches maximum depth, the winch was stopped for about 30 seconds to allow the net to stabilise before starting retrieval. When hauling, propeller thrust was turned off when the net reached a depth of 15 to 20 m; this was to minimise the effects of the propeller action on the net operation and avoids damage of the samples. Target Trawl Whenever interesting targets were seen on the echo-sounder, or large amounts of krill were required for any purpose, target trawls were performed. Once the position of the target was marked, the ship was turned and navigated to run over the target from direction required within navigation capacity. The ship speed was lowered down to below 2.0 knots before hitting the target, so that the net could be lowered down to the desired depth whenever the net reached the target. Fine adjustments were made throughout the trawl by monitoring the echo-sounder in the aft control room. For live krill target trawl, ship speed was kept as slow as possible to avoid any damage to krill. Sample processing for all regular trawl stations: RMT-8 1.Measure the total sample volume (Drain water, then measure using water replacement; mandatory only for the regular hauls) 2.Sort out all Antarctic krill and count their number. If the sample mainly consists of krill and the volume is more than ~1L, a known portion of the whole sample was sub-sampled for the further processing. 3.Stage (TL, Carapace Length, Maturity) of all krill (or subsample), up to 50 to 150 individuals, and digestive gland size (the longest axis) of up to 50 individuals were measured using digital calipers. 4.Other zooplankton groups were immediately sorted out from the catch and their numbers were recorded. Preservation of RMT-8 samples Krill (including those used for onboard demography measurements) were fixed in 10% formalin for their further analysis. Whenever excess amount of krill catch were made, they were sampled and frozen for POP (persistent organic pollutant) measurements, preserved in 80% ethanol for genetic analysis, and frozen under -80C/ liquid nitrogen for chemical analysis. Fish were preserved in formalin, EtOH, or frozen. Squids were preserved in ethanol. RMT-1 1.The whole sample was fixed with 10 % formalin. 2.If the sample volume was too large, then a known proportion of catch was randomly sub-sampled and fixed. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679). Dataset Antarc* Antarctic Antarctic Krill Antarctica Southern Ocean Research Data Australia (Australian National Data Service - ANDS) Antarctic Southern Ocean ENVELOPE(29.92,80.04,-61.67,-69.21) |