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This dataset contains results from the Aurora Australis Voyage 6 1990-91. Surveys of krill and other zooplankton were taken in Prydz Bay, Antarctica between January and February 1991. Species identity and abundance data, length, age, growth rate and mortality rate data were obtained. The major species investigated were Euphausia superba, Euphausia frigidia, Euphausia crystallorophias and Thysanoessa macrura. Other pteropods and cephalopods were also studied. This dataset is a subset of the full cruise.
High-throughput DNA-sequencing data for mesopelagic fish stomach contents sampled during the Kerguelen Axis voyage (January-Februay 2016). Mesopelagic fish form an important link between zooplankton and higher trophic levels in Southern Ocean food webs, however their diets are poorly known. Most of the dietary information available comes from morphological analysis of stomach contents and to a lesser extent fatty acid and stable isotopes. DNA sequencing could substantially improve our knowledge of mesopelagic fish diets, but has not previously been applied. We used high-throughput DNA sequencing (HTS) of the 18S ribosomal DNA and mitochondrial cytochrome oxidase I (COI) to characterise stomach contents of four myctophid and one bathylagid species collected at the southern extension of the Kerguelen Plateau (southern Kerguelen Axis), one of the most productive regions in the Indian sector of the Southern Ocean. Diets of the four myctophid species were dominated by amphipods, euphausiids and copepods, whereas radiolarians and siphonophores contributed a much greater proportion of HTS reads for Bathylagus sp. Analysis of mitochondrial COI showed that all species preyed on Thysanoessa macrura, but Euphausia superba was only detected in the stomach contents of myctophids. Size-based shifts in diet were apparent, with larger individuals of both bathylagid and myctophid species more likely to consume euphausiids, but we found little evidence for regional differences in diet composition for each species over the survey area. The presence of DNA from coelenterates and other gelatinous prey in the stomach contents of all five species suggests the importance of these taxa in the diet of Southern Ocean mesopelagics has been underestimated to date. Our study demonstrates the use of DNA-based diet assessment to determine the role of mesopelagic fish and their trophic position in the Southern Ocean and inform the development of ecosystem models. For more detail, see Clarke LJ, Trebilco R, Walters A, Polanowski AM, Deagle BE (2018). DNA-based diet analysis of mesopelagic fish from the southern Kerguelen Axis. Deep Sea Research Part II: Topical Studies in Oceanography. DOI: 10.1016/j.dsr2.2018.09.001.
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.
Zooplankton were collected with a Rectangular Midwater Trawl (RMT 8+1 net) from 37 sampling sites on and near the Southern Kerguelen Plateau. Specimens of the euphausiid Thysanoessa macrura were selected for cohort analysis, based on lengths, and allometry (dry weights and lengths). Lipids were extracted from the animals to provide a lipid content (%) as a function of dry weight. A small number of individuals was examined further to produce profiles of the main fatty acids and fatty alcohols. Instantaneous growth rate experiments (IGR) were conducted onboard to determine growth rates of males, females and juveniles.
Zooplankton were collected with a Rectangular Midwater Trawl (RMT 8+1 net) from 37 sampling sites on and near the Southern Kerguelen Plateau. The contents of each net were preserved in 5% buffered formaldehyde. This dataset covers the counts of the contents of the RMT8 net and includes the abundances for the euphausiid Thysanoessa macrura and the salp Salpa thompsoni. The contents were identified and counted under a Leica M165C stereo-microscope. A flow meter attached to the mouth of the RMT 8 was used to record the volume of seawater passing through the net. The count for Thysanoessa macrura includes the total of all developmental stages. For the salps abundances are shown for the 2 developmental phases - solitary individuals and aggregates.
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.
Taken from the abstracts of the referenced papers: Distribution patterns of pelagic fish, larvae and juveniles collected by RMT trawls during BROKE survey to CCAMLR Division 58.4.1 were investigated. Nearly 2000 individuals, weighing 1210 g, were collected from approximately 1.5 million cubic metres of the upper 200 m of ocean, supporting the theory that Antarctic ichthyoplankton has low biomass. The collection consisted mainly of P. antarcticum larvae and juveniles and E. antarctica sub-adults, with a range of other notothenioid fish and myctophids. Three distinct biogeographic zones, with characteristic ichthyo- and zooplankton assemblages, were identified. The Oceanic Zone was dominated by myctophids and, in the western reaches, the paralepidid N. coasti. The shelf break zone comprised of myctophids, and the juveniles of notothenioid fish. The shelf zone consisted of notothenioid juveniles and sub-adults. Characteristic water masses and associated zooplankton assemblages were found throughout these three zones. Analysis of fish stomach contents indicated feeding on locally abundant zooplankton taxa. There was niche-partitioning of prey taxa and size classes, between both sympatric species and between different ontogenetic stages. Fish distributions corresponded to known patterns, and extended the geographic range of several species. ##### Zooplankton data from routine 0-200 m oblique trawls were analysed using cluster analysis and non-metric multidimensional scaling to define the communities in Eastern Antarctica (80-150 E), their distribution patterns, indicator species, and species affinities. Three communities were defined based on routine trawls. The Main Oceanic Community comprising herbivorous copepods, chaetognaths, and the euphausiid Thysanoessa macrura dominated the area west of 120 E. The area east of 120 E was dominated by Salpa thompsoni. The third community located in the neritic zone was dominated by Euphausia crystallorophias. Antarctic krill Euphausia superba did not form a distinct community in its own right, unlike previous observations in Prydz Bay. Krill were distributed throughout most of the survey area but generally in higher abundances towards the shelf break. Overall, krill abundance was low compared with previous net surveys in Prydz Bay. Three main types of assemblages were identified based on target trawls. The first group was dominated by krill (mean 1149 individuals per 1000 cubic metres) which represented greater than 99% of Group 1 catches in terms of numbers and biomass. Group 2 comprised the bulk of target trawls and comprised a wide diversity of species typical of the main oceanic community, with a mean abundance approximately half of that observed in the routine trawls. The third group comprised trawls in the neritic zone dominated by E. crystallorophias. No salp-dominated aggregation was found. While E. superba did not dominate a distinct community geographically as seen in previous Prydz Bay surveys, it did dominate discrete layers or aggregations, showing that both horizontal and vertical separation of communities exist. ##### The download file contains the following documents: 199596040Composition.csv 199596040Density.csv 199596040Biomass.csv
These data were collected during the BROKE-West voyage of the 2005-2006 season. They are numbers of krill larvae per cubic metre of water at each of the stations at which data were collected. The data cover three species of Antarctic krill - Euphausia crystallorophias, Euphausia superba and Thysanoessa macrura. The superba data have been published in the Kawaguchi et al paper, "Krill demography and large-scale distribution in the Western Indian Ocean sector of the Southern Ocean (CCAMLR Division 58.4.2) in Austral summer of 2006". The data for the other species will be presented in a forthcoming paper by Kerrie Swadling. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).