This dataset contains data files, processing templates and documentation relating to the BROKE-West multifrequency echosounder (acoustic) survey carried out from the RSV Aurora Australis in the austral summer of 2005/06 (ASAC project 2655). The primary aim of the acoustic survey was to describe the distribution and abundance of Antarctic krill (Euphausia superba) in CCAMLR Division 58.4.2. However, these data are also relevant for studies of other sound-scattering targets detected by the echosounder system, for example other pelagic taxa or the seafloor. The dataset is a collection of *.csv data files, *.ev processing files and *.pdf documentation files, organised into 4 categories: 1. Acoustic survey: data files relating to the transects undertaken for the acoustic survey 2. Acoustic data processing: metadata files, processing templates and documentation relating to the collection and processing of the acoustic data 3. Acoustic results: results arising from the processing of the raw data. The raw data are described in a separate metadata record - "AAD Hydroacoustics hard disks - data collected from Southern Ocean cruises..." 4. Ancillary data: additional non-acoustic data used during the processing of the acoustic data The file "data_fields.pdf" lists and describes the fields in each of the *.csv data files. The file "processing_methods.pdf" provides a synopsis of the methods by which the raw acoustic data were collected and processed. The BROKE-West survey was conducted on voyage 3 of the Aurora Australis during the 2005-3006 season. It was intended to be a comprehensive biological and oceanographic survey of the region between 30 degrees and 80 degrees east.

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.

Samples were collected at trawl stations (approximately every second CTD station), as well as opportunistically when something interesting was spotted on the Echosounder. The samples were collected with an RMT-1 plankton net and preserved in Steedman's solution. Upon returning to Australia, the samples were passed onto Kerrie Swadling, who split them with a Folsom plankton splitter and counted between 400 and 1300 animals. Every organism was identified to the lowest possible taxon - in the case of copepods, usually to species and stage level. Other taxa are to species wherever possible. All the animals were counted and the results are expressed as abundance per 1000 cubic m. The data in the spreadsheet represent a species x site matrix. The excel spreadsheet entitled 'List of major samples and activities BROKE West.xls' is a summary of the sort of samples that were collected at each station, and the purpose for which they were collected. More detailed notes about the collection of the samples are presented in the Quality field. Further information about the Trawl stations can be found in the parent BROKE-West metadata record. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679). The fields in these excel spreadsheets are: Station Number Species Date Latitude Longitude Trawl Type Formalin - whether the samples were fixed in formalin IGR - whether the instantaneous growth rate experiment was performed Genetics - preserved in ethanol, samples retained for genetic experiments Frozen - samples frozen at -85 degrees C for chemical analysis POP - samples analysed for Persistent Organic Pollutants Density Contrast - whether the density contrast of the krill were measured Isotopes - samples retained for isotope analysis Frozen DG - digestive gland samples were frozen Ethanol (Squid) - ethanol fixed squid were retained Frozen (Fish) - frozen fish samples were retained Formalin (Fish) - formalin fixed fish samples were retained Ethanol (Fish) - ethanol fixed fish samples were retained Demography - demographic parameters were collected Other - various purposes, occasionally noted in the comments field Comments The spreadsheet 'List of major samples and activities BROKE West.xls' is marked with solid black circles, or empty white circles - the empty white circles represent Euphausia crystallorophias samples. The solid black circles represent Euphausia superba in columns F-K, M and R. In the other columns they will either represent the animal as marked (eg squid), or may be a collection of anything.