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EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES > ARTHROPODS > CRUSTACEANS

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  • Metadata record for data from ASAC Project 668 See the link below for public details on this project. From the abstracts of some of the referenced papers: Body shrinkage may be one of the strategies that Antarctic krill use to cope with food scarcity, particularly during winter. Despite their demonstrated ability to shrink, there are only very limited data to determine how commonly shrinkage occurs in the wild. It has been previously shown that laboratory-shrunk krill tend to conserve the shape of the eye. This study examined whether the relationship between the eye diameter and body length could be used to detect whether krill had been shrinking. By tracking individuals over time and examining specimens sampled as groups, it was demonstrated that fed and starved krill are distinguishable by the relationship between the eye diameter and body length. The eye diameter of well-fed krill continued to increase as overall length increased. This created a distinction between fed and starved krill, while no separation was detected in terms of the body length to weight relationship. Eye growth of krill re-commenced with re-growth of krill following shrinkage although there was some time lag. It would take approximately 2 moult cycles of shrinkage at modest rates to significantly change the eye diameter to body length relationship between normal and shrunk krill. If krill starve for a prolonged period in the wild, and hence shrink, the eye diameter to body length relationship should be able to indicate this. This would be particularly noticeable at the end of winter. A series of experiments was carried out to examine the relationship between feeding, moulting, and fluoride content in Antarctic krill (Euphausia superba). Starvation increased the intermolt period in krill, but had no effect on the fluoride concentration of the moults produced. Addition of excess fluoride to the sea water had no direct effect on the intermoult period, the moult weight, or moult size. Additions of 6 micrograms per litre and 10 micrograms per litre fluoride raised the fluoride concentrations of the moults produced and the whole animals. The whole body fluoride content varied cyclically during the moult cycle, reaching a peak 6 days following ecdysis. Fluoride loss at ecdysis could largely be explained by the amount of this ion shed in the moult.

  • This data were collected on the sixth Nella Dan voyage of a long term field survey project being conducted by the Australian Antarctic Division, to collect distribution, abundance and population structure data for the krill Euphausia superba in the Prydz Bay region, Antarctica. This voyage, the Australian Antarctic Marine Biological Ecosystem Research 1986/1987 (AAMBER 86/87) cruise, operated between February and April 1987. During March, a survey of the krill population and zooplankton community was conducted, to determine the late summer distribution and abundance of krill, especially the larvae. This was done as a follow up to SIBEX II in mid-summer (Janurary) 1985. The major species investigated were Euphausia superba, Euphausia frigidia, Euphausia crystallorophias and Thysanoessa marcuria. Phytoplankton pigment analysis was also conducted at each CTD station site.

  • This dataset provides a guide to the Euphausiacea of the Southern Ocean, in particular Euphausia superba Dana (Antarctic krill). It lists all the known species and with illustrated diagrams provides a guide to their taxonomic identification. The document is available for download as a pdf from the URL given below.

  • In March 2018, 23 environmental DNA (eDNA) samples (2 L of filtered seawater) were collected between Hobart, Tasmania and subantarctic Macquarie Island. These samples were processed using six different genetic metabarcoding markers targeting different taxonomic groups within the metazoan clade: A broad cytochrome c oxidase subunit I (COI) marker targeting all metazoans, and five different 16S markers targeting fish, cephalopods and crustaceans (one degenerate marker), fish (two markers of different lengths), cephalopods (one marker) and crustaceans (one marker). The aim of this study was to identify an ideal set of molecular markers to identify as many metazoan species as possible from small environmental samples, with a particular focus on vertebrates, crustaceans and cephalopods. The data and methods are described in the word file "V4 2018 eDNA group specific markers.docx", results are summarised in the excel file "Marker.detection.xlsx" and additional sample information is in the excel files "2018_11_07_eDNA-sample-info.xls" and "sample.map.csv". Each genetic marker used in this study has its own folder, containing the raw FASTQ sequencing data, the processed FASTA sequencing data, the bioinformatics processing pipeline, the zOTU fasta file, BLAST output, MEGAN output and curated zOTU table. For further explanations please refer to the word file "V4 2018 eDNA group specific markers.docx".

  • This dataset contains results from the Antarctic Division BIOMASS Experiment II (ADBEX II) cruise of the Nella Dan. This is the third cruise of six, and follows the ADBEX I cruise made during late 1982. ADBEX II was to have been an international experiment, Second International BIOMASS Experiment I (SIBEX I), in cooperation with Japan, South Africa and France, however due to the delay of a supply program Australia's participation was cancelled. ADBEX II is the result of a reduced sampling program carried out during the resupply of Davis and Mawson stations. Surveys of krill and other zooplankton were taken off Antarctica in the Australian sector (Mawson to Davis region) and Prydz Bay in January 1984. Species identity and abundance data were obtained. The major species investigated were Euphausia superba, Euphausia frigidia, Euphausia crystallorophias and Thysanoessa marcuria. Other pteropods and cephalopods were also studied. Results from hydroacoustic surveys of krill biomass were also obtained, as well as CTD and chlorophyll data. Summary results are listed in the documentation.

  • This dataset contains results from the Antarctic Division Biomass Experiment (ADBEX I) cruise of the Nella Dan. This cruise is the second in a series of six cruises, and follows the First International BIOMASS Experiment (FIBEX) in early 1981, documentation of which can be found in ANARE Research Notes 7, or by searching the metadata records for FIBEX. ADBEX I operated between November and December 1982, and studied the distribution and abundance of krill (Euphausia superba). Surveys of krill and other zooplankton were taken off Antarctica in the Australian sector (Mawson to Davis region) and Prydz Bay. The major species investigated were Euphausia superba, Euphausia frigidia, Euphausia crystallorophias and Thysanoessa marcuria. Other pteropods and cephalopods were also studied. Physical and chemical oceanography data were also obtained at some stations, as well as phytoplankton samples. Summary results are listed in the documentation.

  • This dataset contains hydroacoustic results from the First International Biomass Experiment (FIBEX) cruise of the Nella Dan. This cruise is the first in a series of six cruises, performing a long term survey of krill and other zooplankton distribution and abundance. FIBEX was an international project, done in co-operation with Japan, South Africa and France. Fourteen transects were made by Australia off Antarctica in the Australian sector (Mawson to Davis region) and Prydz Bay in January to March 1981, covering a survey area of 1.09x10^6 square kilometers. Quantitative and geographic krill distribution, abundance, mean and variance of the krill weight density, and total krill biomass were obtained. The standing stock of krill for the Prydz Bay region was calculated at the second workshop to be approximately 1.3 million tonnes, or 1.6 million tonnes if extrapolated over the survey area of the SIBEX II cruise. Temperature, nutrient and salinty data were also obtained, as well as trawl results. Summary results are listed in the documentation. A scanned copy of the acoustics log book from the voyage is available for download from the provided URL.

  • Metadata record for data from ASAC Project 587 See the link below for public details on this project. From the abstracts of some of the referenced papers: The concentration of fluoride in the body parts of a range of Antarctic crustaceans from a variety of habits was examined with the aim of determining whether fluoride concentration is related to lifestyle or phylogenetic grouping. Euphausiids had the highest overall fluoride concentrations of a range of Antarctic marine crustaceans examined; levels of up to 5477 micro grams per gram were found in the exoskeleton of Euphausia crystallorophias. Copepods had the lowest fluoride levels (0.87 micrograms per gram) whole-body); some amphipods and mysids also exhibited relatively high fluoride levels. There was no apparent relationship between the lifestyle of the crustaceans and their fluoride level; benthic and pelagic species exhibited both high and low fluoride levels. Fluoride was concentrated in the exoskeleton, but not evenly distributed through it; the exoskeleton of the head carapace and abdomen contained the highest concentrations of fluoride, followed by the feeding basket and pleopods, and the eyes. The mouthparts of E. superba contained almost 13,000 microgams F per gram dry weight. Antarctic krill tail muscle had low levels of fluoride. After long-term (1 to 5 year) storage in formalin, fluoride was almost completely lost from whole euphausiids. A series of experiments was carried out to determine the relationship between feeding, moulting, and fluoride content in Antarctic krill (Euphausia superba). Starvation increased the intermoult period in krill, but had no effect on the fluoride concentrations of the moults produced. Addition of excess fluoride to the sea water had no direct effect on the intermoult period, the moult weight, or moult size. Additions of 6 micrograms per litre and 10 micrograms per litre fluoride raised the fluoride concentrations of the molts produced and of the whole animals. The whole body fluoride content varied cyclically during the moult cycle, reaching a peak 6 days following ecdysis. Fluoride loss at ecydsis could largely be explained by the amount of this ion shed in the moult. This work was completed as part of ASAC projects 41 and 587 (ASAC_41, ASAC_587).

  • This record describes the collection of marine fauna sampled from coastal areas of the Vestfold Hills in 1999. The project was undertaken to compile morphometric data on Weddell seal prey species. Benthic prawns i.e. Chorismus antarcticus and Notocrangon antarcticus, are common Weddell prey species at the Vestfold Hills. We fished for prawns using mesh traps (40 x 20 x 20 cm3). The traps were set at Magnetic Island in May, and in Ellis Fjord in December. The site near Magnetic Island was chosen when the fast-ice fractured enabling the gear to be set in natural tracts of open water. The site in Ellis Fjord was chosen on the basis of published information regarding bathymetry and the range of depths inhabited by prawn species. We waited until December to sample in Ellis Fjord so that the fishing hole did not refreeze. Prawns were caught only in Ellis Fjord and only when the traps were deployed open i.e. with zips on the doors to get the catch out left undone. Approximately 50 prawns of various sizes were caught over three days at the same location, 200 m east of the crossing at Ellis Narrows. The catch has been stored whole in the Australian Antarctic Division freezer in Hobart. Bycatch included amphipods and Notothenid fish at Magnetic Island, and echinoderms, holothurians and Notothenid fish in Ellis Fjord. Some of the bycatch were retained and are stored frozen with the prawns. The linked dataset contains the measurements of length, mass, carapace length and sex (juvenile, male, female) of the prawn catch. All of the prawns were Chorismus antarcticus. The adult females were brooding eggs. The best fit linear regressions were y = 0.3529x - 2.4824, (R2 = 0.9504) for carapace length to predict body mass, and y = 3.5267x + 4.5846 (R2 = 0.9544) for carapace length to body length. The associated URLs contain all of the data, including spreadsheet of data, a scatterplot of the length mass relationship, and a mass frequency histogram of the catch. The fields in this dataset are: Chorismus ID carapace length (mm) body length (mm) mass (g) sex

  • The natural world is a mosaic of different habitats and biological communities; the tiles of this mosaic may be small but the patterns formed can be measured at many scales from metres to thousands of kilometres. Understanding these patterns is important to protecting biodiversity. We will identify major scales of variability in Antarctic coastal habitats, biological communities and processes that create them. We will also document scales of impacts caused by humans in Antarctica and potential impacts of future climate change driven by key processes (changes in sea-ice). This information will contribute to environmental management to protect Antarctic coastal ecosystems. This record is the parent record for all metadata records relating to ASAC project 2201. See the child metadata records for access to the data arising from this project. See the project link for a full listing of personnel involved in this project.