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Distribution and abundance of zooplankton, krill and fish were observed on the K-axis transect using deployments of RMT1+8 net. Towing speed of the RMT1+8 were approximately 2 knots. All krill, fish and squid in the catch were sorted, identified to species and counted. The density at each station were determined from the counts per calibrated flow-meter readings attached to the net. Morphometric measures were taken and, for larger taxa. List of files K-Axis Morph combined_for data centre.xlsx: Morphological data for all krill and zooplankton captured in RMT-8 net haul. RMT data entry_v1_for data centre.xlsx: Trawl data. RMT8 filtered volume_for data centre.xlsx: Filtered volume for each haul. Map_all.tif: Map showing all trawl stations. Map_RMTR.tif: Map showing only regular trawl stations. Map_RMTT.tif: Mapn showing only target trawl stations. K-Axis description This dataset includes biological data from “K-Axis voyage, 2016 and “Voyage 3, 2015”. [Data from K-Axis voyage, 2016] Distribution and abundance of zooplankton, krill and fish were observed on the K-axis transect using deployments of RMT1+8 net. Towing speed of the RMT1+8 were approximately 2 knots. All krill, fish and squid in the catch were sorted, identified to species and counted. The density at each station were determined from the counts per calibrated flow-meter readings attached to the net. Morphometric measures were taken and, for larger taxa. -List of files- K-Axis Morph combined_for data centre.xlsx: Morphological data for all krill and zooplankton captured in RMT-8 net haul. Map_all.tif Map_RMTR.tif Map_RMTT.tif RMT data entry_v1_for data centre.xlsx: Trawl data. RMT8 filtered volume_for data centre.xlsx: Filtered volume for each haul. [Data from Voyage 3, 2015] The Australian Antarctic research and resupply vessel, RV Aurora Australis, was directed to undertake an opportunistic marine science survey for 17 days during 21 February to 10 March 2015 using ship time that became available due to unexpectedly favourable ice conditions for Mawson station resupply. The purpose of this opportunistic Marine Science work was to assess: 1. The spatial variability, particularly along the shelf break, of the prey field for penguins, flying seabirds and marine mammals in East Antarctica. 2. The small scale variability of prey in key foraging locations near to land-based colonies of penguins and flying seabirds in East Antarctica. 3. Feasibility and potential of utilising annual station resupply voyages as a cost effective means to undertake monitoring and research to better understand the ecosystem in the region. The survey completed 5 acoustic box surveys including a total of 53 RMT target and routine trawls, 6 demersal trawls, 131 phytoplankton samples from underway sampling, and 214 hourly observations of predators. These activities were successfully supervised remotely. -List of files- emm-15-22.pdf: Prelminary report of the voyage to CCAMLR WG-EMM Figure_V3_all_euphausiids.pdf: Map of Euphausiid abundance distribution. Figure_V3_Clione_antarctica.pdf: Map of Clione antarctica abundance distribution. Figure_V3_crystal_krill.pdf: Map of Euphausia crystallorophias abundance distribution. Figure_V3_frigida.pdf: Map of Euphausia frigida abundance distribution. Figure_V3_larval_fish_abundances.pdf: Map of fish larvae abundance distribution. Figure_V3_superba.pdf: Map of Antarctic krill abundance distribution. Figure_V3_tmacrura.pdf: Map of Thysanoessa macrura abundance distribution. V3_final_for data centre.xlsx: Trawl station data and density data of each taxa caught. Voyage 3 Marine Science Program Final.docx: Voyage report.
Krill, salps and pteropods were collected with an RMT8 net during the K-Axis cruise. Specimens were removed from the samples, measured and frozen at -20C until ready for analysis in Hobart. Individuals of known species were dried at -60C, ground to a fine powder, encapsulated into tin cups and analysed with an ICP-MS in the Central Science Laboratories, University of Tasmania. Samples were analysed for delta15N and delta13C. The salp was the common Southern Ocean species Salpa thompsoni and the krill were Euphausia superba, E. triacantha, E. frigida and Thysanoessa macrura. A small number (2) of the siphonphore Diphyes antarctica were also analysed. Pteropods analysed included both shelled (thecosomes) and naked (gymnosomes) pteropods. Columns E-O in the Pteropods worksheet in the spreadsheet are expressed as ratios.
The data describe all zooplankton species abundance values estimated at each rectangular midwater trawl (RMT 1+8) target and routine sampling site collected during the 2021 TEMPO voyage on R/V Investigator. During the TEMPO voyage, zooplankton were collected using the RMT 1+8 plankton net and sorted down to the lowest taxonomic level possible. The supporting data set, in CSV format, feature abundances estimated from RMT+1 samples only. The data file is named allzooplankton.csv. The fields (columns) in the file are: "Site" – sampling site ID for each routine (RXX) and target (TXX) trawl using RMT1+8. "Date" – date of each sample collected (ie. target or routine trawl) [dd/mm/yyyy]. "Latitude" – latitude of each trawl [degrees] (-dd.ddddd). "Longitude" – longitude of each trawl [degrees] (dd.ddddd). "Chla" – Integrated estimate of chlorophyll-a (mg m^-2) averaged at depths between 10 to 200 m, which aligns with the section of the water column where zooplankton were sampled. "Depth" – Bathymetric depth estimated at each sampling station. "MLD_03" – Mixed layer depth (m). Not used in final analysis. "MLD_05" – Mixed layer depth (m). Not used in final analysis. "MLD_N2max" – Mixed layer depth (m) where the N^2 maximum is found, i.e., the pycnocline. "CT_200" – Absolute temperature (°C) averaged at depths between surface and 200 m maximum net sampling depth. Values are derived from in situ CTD measurements at each sampling site. "SA_200" – Absolute salinity (g kg^-1) averaged at depths between surface and 200 m maximum net sampling depth. Values are derived from in situ CTD measurements at each sampling site. "IceMeltDays" – Number of days since sea ice melted calculated from daily passive microwave estimated percent sea ice concentration taken from the National Snow and Ice Data Centre. "m_to_Ice" – Distance (m) estimated from sampling site to edge of ice. "IceConc" – Actual ice concentration value (%). It is the percentage of an area covered in sea ice. The remaining columns are zooplankton species abundances (individuals per 1000 cubic metres) estimated from count data, volume of original sample, split of sample analysed under the microscope and calibration of the flowmeter: "R.gigas" – Rhincalanus gigas, copepod "C.propinquus" – Calanus propinquus, copepod "C.simillimus" – Calanus simillimus, copepod "C.acutus" – Calanoides acutus, copepod "Metridia sp." – Metridia species, copepod "M.gerlachei" – Metridia gerlachei, copepod "Paraeuchaeta sp." – Paraeuchaeta species, copepod "Pleuromamma sp." – Pleuromamma species, copepod "Oncaea" – Oncaea species, copepod "O.antarctica" – Oncaea antarctica, copepod "Neo tonsus" – Neocalanus tonsus, copepod "Neo gracilis" – Neocalanus gracilis, copepod "Stephos longipes" – Stephos longipes, copepod "Ctenocalanus sp." – Ctenocalanus species, copepod "Microcal pygmaeus" – Microcalanus pygmaeus, copepod "Oithona similis" – Oithona similis, copepod "Oithona frigida" – Oithona frigida, copepod "Heterhabdus australis" – Heterorhabdus australis, copepod "Heterhabdus sp." – Heterorhabdus species, copepod "Harpacticoid" – Harpacticoid species, copepod "Haloptilus sp." – Haloptilus species, copepod "Candacia sp." – Candacia species, copepod "Solecithricella sp." – Solecithricella species, copepod "Clausocalanus breviceps" – Clausocalanus breviceps, copepod "Clausocalanus laticeps" – Clausocalanus laticeps, copepod "Clausocalanus sp." – Clausocalanus species, copepod "Aetideops antarctica – Aetideopsis antarctica, copepod "Aetide minor" – Aetideopsis minro, copepod "Euchirella rostromanga" – Euchirella rostromanga, copepod "Heterostylites longicornis" – Heterostylites longicornis, copepod "Gaidius tenuispinus" – Gaidius tenuispinus, copepod "Gammaridean amphipod" – Gammaridean, amphipod "T.gaudichaudii" – Themisto gaudichaudii, amphipod "Parathemisto sp." – Parathemisto species, amphipod "Hyperia antarctica" – Hyperia antarctica, amphipod "Hyperia sp." – Hyperia species, amphipod "Hyperiella dilatata" – Hyperiella dilatata, amphipod "Hyperiella antarctica" – Hyperiella antarctica, amphipod "Hyperiella sp." – Hyperiella species, amphipod "Hyperiella macronyx" – Hyperiella macronyx, amphipod "Hyperiella dilatate" – Hyperiella dilatata, amphipod "Primno macropa" – Primno macropa, amphipod "Hyperoche medusarum" – Hyperoche medusarum, amphipod "E.crystallorophius" – Euphausia crystallorophius, krill "E.superba" – Euphausia superba, krill "T.macrura" – Thysanoessa macrura, krill "Krill (other)" – unidentified krill species "Decapod" – decapod species "L.h.antarctica" – Limacina helicina antarctica, pteropod "C.pyramidata" – Clio pyramidata, pteropod "Clione antarctica" – Clione antarctica, pteropod "S.australis" – Spongiobranchaea australis, pteropod "Gymnosome" – unidentified gymnosome species, pteropod "Ptero egg mass" – pteropod egg mass "Tiarrana rotunda" – Tiarrana rotunda, polychaete "Traviopsis/Typhloscoplex" – Traviopsis species or Typhloscoplex species, polychaete "Phalacrophorus pictus" – Phalacrophorus pictus, polychaete "Rhynchon brongraini" – Rhynchonerella brongraini, polychaete "Rhynchoneralla petersii" – Rhynchonerella petersii, polychaete "Rynchonerella sp." – Rhynchonerella species, polychaete "Vanadis sp." – Vanadis species, polychaete "Vanadis longissima" – Vanadis longissima, polychaete "Vanadis antarctica" – Vanadis antarctica, polychaete "Pelagobia longicerrata" – Pelagobia longicerrata, polychaete "Iopsilidae worm" – Iopsilidae species, polychaete "Polychaete" – unidentified polychaete worm "Furry worm" – unidentified "furry" polychaete worm "Larval worm" – unidentified "larval" polychaete worm "Tiny worm" – unidentified tiny-sized polychaete worm "Tomopteris septentrionalis" – Tomopteris septentrionalis, tomopteris "Tomopteris sp." – Tomopteris species, tomopteris "Phalacrophorus sp." – Phalacrophorus species, tomopteris "Isopod" – isopod worm "Tintinnids" – tintinnid species "Neogloboquadrina pachyderma" – Neogloboquadrina pachyderma, foraminifera "Siphonophore" – Siphonophore species "Appendicularian" – Appendicularian species "Ostracod" – unidentified ostracod species "Alacia hettacra" – Alacia hettacra, ostracod "Metaconchoecia skogsbergi" – Metaconchoecia skogsbergi, ostracod "Deeveyoecia arcuata" – Deeveyoecia arcuata, ostracod "Austrinoecia isocheira (less than 1mm)" – Austrinoecia isocheira ostracod, less than 1 mm in body size "Boroecoa antipoda" – Boroecoa antipoda, ostracod "Sagitta maxima" – Sagitta maxima, chaetognath "Sagitta serratodentata" – Sagitta serratodentata, chaetognath "Sagitta gazella" – Sagitta gazella, chaetognath "Sagitta marri" – Sagitta marri, chaetognath "Sagitta sp." – Sagitta species, chaetognath "Eukrohnia hamata" – Eukrohnia hamata, chaetognath "Unknwn chaetognath" – Unidentified species of chaeotognath "Fish egg" – fish egg "Larval fish" – unidentified species of larval fish "jelly nubby tentacles" – unidentified species of cnidarian (with "nubby" tentacles) "jelly w/no tentacles" – unidentified species of cnidarian (with no tentacles) "jelly" – unidentified species of cnidarian "TOTALS" – tally of total abundances across each row (total abundances across all zooplankton species for each sampling site)
Metadata record for data from ASAC Project 229 See the link below for public details on this project. From the abstracts of some of the referenced papers: In January 1985 a net sampling survey was carried out on the distribution and abundance of euphausiid larvae in the Prydz Bay region. Euphausia superba occurred in low abundance, probably due to sampling preceding the main spawning period. Thysanoessa macrura occurred throughout the study area in consistently high abundance. Euphausia crystallorophias as marginally more abundant within its restricted range. Distinct north-south variations in larval age and development stages of T. macrura were observed indicating regional differences in spawning. Euphausia frigida was mainly confined to the upper 200 m of the Antarctic Circumpolar Current. Larvae originating on the shelf moved rapidly west in the East Wind drift. E. crystallorophias had the same westward dispersion, but some larvae appeared to return eastward via the Prydz Bay Gyre and remain in the region. The data indicate that most E. superba larvae, providing they survive injurious cold temperature and food deprivation, will leave the area, suggests that Prydz Bay krill may not be a self sustaining stock. ##### This paper presents results of net sampling carried out in four marine science cruises between 1981 and 1985, in the Prydz Bay region of Antarctica by the Australian Antarctic Division. Krill exhibited a patchy distribution and overall low abundance. The majority of sampling sites in January 1985 returned no post-larval krill or densities of less than 1 individual per 1000 cubic metres. The estimated mean abundance of E. superba in January 1985 was 6 indivduals or 2 g (wet wt.) per 1000 cubic metres integrated for the upper 200m of the water column which represented 3.4% of the total zooplankton biomass. No more than five years-groups, including the larvae, were observed in Prydz Bay, with mean lengths of groups 1+, 2+, 3+ and 4+ being 24, 38, 46 and 53 mm (standard 1), respectively in the middle of January. A high proportion of naupliar stages observed in January 1985 indicated that spawning in Prydz Bay begins in January and examination of adult maturation showed that the spawning continues at least to March. ##### Sixty female Antarctic krill (Euphausia superba Dana) spawned in shipboard experiments and the interval between egg-laying and ecdysis was noted. The number of eggs laid per female ranged from 263-3662, most females produced only one batch of eggs before moulting, and the post spawn ovaries of all females contained few, if any, mature oocytes. As reported in other studies, the total number of eggs produced per female was not well correlated with body size. Females appeared to spawn at all times during the moulting cycle and although no diurnal rhythm in spawning was observed, moulting occurred mainly at night-time despite the animals being kept in near-constant darkness. No evidence of synchronous moulting was detected. ##### Data from this project were collected on five Antarctic voyages: HIMS - Heard Island Marine Science - 1990-05-04 - 1990-07-01 AAMBER II - Australian Antarctic Marine Biological Ecosystem Research II - 1991-01-3 - 1991-03-19 FISHOG - Fish and Oceanography - 1992-01-09 - 1992-03-27 KROCK - Krill and Rocks - 1993-01-05 - 1993-03-09 BROKE - Baseline Research on Oceanography, Krill and the Environment - 1996-01-02 - 1996-03-31 All data are available in the download file.