Observations of seabirds at sea have been made by observers on Australian Antarctic ships in the Prydz Bay region during most seasons since 1980/81. Approximately 32000 observations of 26 main species were made from the 1980/81 to 2001/02 seasons. These observations provide a two-decade history of seabird activity in this region of the Antarctic. This project used clustering techniques to identify the communities within the seabird populations. Summary of results We found three distinct communities of seabirds within Prydz Bay. The first comprised all nine species of seabird which breed in the Prydz Bay area (emperor and Adelie penguins, snow, Cape, and Antarctic petrels, southern giant petrels, southern fulmars, Wilson's storm petrel, and south polar skuas). The second comprised those species which breed in sub-Antarctic or temperate regions and forage in Prydz Bay in the summer months (including many species of albatrosses and shearwaters). There was an overlap of these two communities which had a broad mix of species. The spatial and temporal ranges of these communities is given in this data set. The raw data for this dataset was generated through ASAC project 2208 - Distribution and abundance of seabirds in the Southern Indian Ocean, 1980/81+ (ASAC_2208_seabirds). The fields in this dataset are: Year Month Day Hour Minute Voyage Latitude Longitude Assemblage Constancy Fidelity

Minicosm design: Three successive experiments to a maximum incubation of 14 days were performed from mid November to early January in the summer of 2002/03 in a temperature controlled shipping container housing six 500 L polythene tanks or minicosms. Domes of UV transmissive PMMA in the roof of the container directly above the minicosms allowed ambient sunlight to be reflected to the tanks through tubes of anodised aluminium. These tubes reflected greater than 96% of the incident radiation irrespective of wavelength. Light perturbation to each minicosm was achieved by screening materials that attenuated UV wavelengths. UV stabilised polycarbonate removed wavelengths shorter than 400 nm, transmitting only photosynthetically active radiation (PAR) and provided the control treatment (PAR). In minicosm 2, a mylar screen removed UVB wavelengths (280 - 320 nm), providing a treatment (UVA) with PAR and UVA. Minicosms 3, 4 and 5 (UVB1, 2 and 3 respectively) were screened by borosilicate glass of 9, 5, and 3 mm thickness, transmitting ambient light (including UVR) at the equivalent water depths (ED, k=0.4) of 7.15, 5.38 and 4.97 meters respectively. Minicosm 6 (UVB4) was screened with PMMA that transmitted ambient light at an ED of 4.43 m. Light measurements: Measurements of downwelling UV and PAR were obtained using biometer and Licor sensors mounted on the roof of the minicosm container. A Macam, double grating spectroradiometer measured the spectral irradiance on the roof of the container. This was then weighted with the erythemal action spectrum and correlated to that obtained by the UV biometer. The Macam was used to measure the spectral irradiance at the cross of the UV biometer. The spectral intensity of light wavelengths were measured laterally and vertically in the minicosm screened only by UV-transmissive PMMA irradiance. These measurements were used to model the light field within the minicosm. In all other light treatments the Macam measured the spectral irradiance immediately below the water surface and in the centre of the minicosm. The model was then used to predict the spectral distribution and intensity of other light treatments. These measurements were repeated at interval throughout the season to determine whether solar elevation influenced transmission of ambient downwelling irradiance to the minicosms. UV and PAR sensors fixed to the outside of the minicosm container, together with the modelled light climates within each minicosm beneath each light treatment, predicted the quantify the light to which each experimental treatment was exposed. This work was conducted as part of ASAC project 2210. The download file contains three excel spreadsheets, plus three accompanying word documents which provide detailed methods used in the collection of these data, plus more information about the experiments. The fields in this dataset are: Day Treatment Carbon Hydrogen Nitrogen C:N ratio

This dataset contains 102 depth measurements of the water column in Long and Tryne fjords, which are in the northern Vestfold Hills, Prydz Bay, Antarctica. Sea ice thickness and snow thickness were recorded simultaneously. The motivation for this project has been to yield a description of the pupping and moulting habitat of Weddell seals. This information will assist the interpretation of 25+ years of data on seal distribution within that area. Our data were collected between 7th and 13th December 1999. The measurement sites were chosen according to geographical features; their exact location was determined by GPS with an accuracy of about 25m. At each site a 5cm diameter hole was drilled through the sea ice and a weighted measurement tape was lowered through the ice-hole to the bottom. Water depths were measured to the nearest centimetre; ice and snow thicknesses were measured to the nearest millimetre. A minimum depth of less than 3m was found in a narrow channel between small islands immediately west of Shirokaya Bay. The maximum depth of the water column was 222m in the middle basin of Long Fjord. The tidal range for the measured days was less than 0.5m, with tidal corrections applied to the raw data. Water samples were taken in Breid Basin and the middle basin of Long Fjord. These and water samples taken in Snezhnyy Bay [pers. comm. J. Laybourn-Parry, 1999] show aerobic and relatively fresh water for all upper basins. This indicates that even the far basins of both fjords are well mixed despite the drainage of large volumes meltwater from the Antarctic plateau into the fjords. See related URL for data and a spatial summary of the data. See Entry: long_tryne_bathy for an interpolation of bathymetry made using the Topogrid command within the ArcInfo GIS software, version 8.0.2. Coastline and spot height (heights above sea level) data, extracted from the Australian Antarctic Data Centre's Vestfold Hills topographic GIS dataset (see Entry: vest_hills_gis), was also used as input data to optimise the interpolation close to the coastline. The fields in this dataset are: day weighpoint lat(dd) long(dd) ice (cm) freeboard(cm) snow(cm) depth(m)

Minicosm design: Three successive experiments to a maximum incubation of 14 days were performed from mid November to early January in the summer of 2002/03 in a temperature controlled shipping container housing six 500 L polythene tanks or minicosms. Domes of UV transmissive PMMA in the roof of the container directly above the minicosms allowed ambient sunlight to be reflected to the tanks through tubes of anodised aluminium. These tubes reflected greater than 96% of the incident radiation irrespective of wavelength. Light perturbation to each minicosm was achieved by screening materials that attenuated UV wavelengths. UV stabilised polycarbonate removed wavelengths shorter than 400 nm, transmitting only photosynthetically active radiation (PAR) and provided the control treatment (PAR). In minicosm 2, a mylar screen removed UVB wavelengths (280 - 320 nm), providing a treatment (UVA) with PAR and UVA. Minicosms 3, 4 and 5 (UVB1, 2 and 3 respectively) were screened by borosilicate glass of 9, 5, and 3 mm thickness, transmitting ambient light (including UVR) at the equivalent water depths (ED, k=0.4) of 7.15, 5.38 and 4.97 meters respectively. Minicosm 6 (UVB4) was screened with PMMA that transmitted ambient light at an ED of 4.43 m. Light measurements: Measurements of downwelling UV and PAR were obtained using biometer and Licor sensors mounted on the roof of the minicosm container. A Macam, double grating spectroradiometer measured the spectral irradiance on the roof of the container. This was then weighted with the erythemal action spectrum and correlated to that obtained by the UV biometer. The Macam was used to measure the spectral irradiance at the cross of the UV biometer. The spectral intensity of light wavelengths were measured laterally and vertically in the minicosm screened only by UV-transmissive PMMA irradiance. These measurements were used to model the light field within the minicosm. In all other light treatments the Macam measured the spectral irradiance immediately below the water surface and in the centre of the minicosm. The model was then used to predict the spectral distribution and intensity of other light treatments. These measurements were repeated at interval throughout the season to determine whether solar elevation influenced transmission of ambient downwelling irradiance to the minicosms. UV and PAR sensors fixed to the outside of the minicosm container, together with the modelled light climates within each minicosm beneath each light treatment, predicted the quantify the light to which each experimental treatment was exposed. This work was conducted as part of ASAC project 2210. The download file contains three excel spreadsheets, plus three accompanying word documents which provide detailed methods used in the collection of these data, plus more information about the experiments. The fields in this dataset are: Day Treatment UVA UVB PAR - photosynthetically active radiation

Metadata record for data from ASAC Project 1342 See the link below for public details on this project. ---- Public Summary from Project ---- This project involves field trialling of software written as part of ASAC project 1212 (2000-2001) to determine sea-ice thickness in real-time from ship-borne electromagnetic induction measurements. Computer simulation of ship- and helicopter-borne electromagnetic induction measurements over realistic sea-ice structures will also be performed in order to assess the suitability and cost-effectiveness of helicopter-mounted systems for future Antarctic sea-ice thickness measurements. Equipment used in this study were the IBEO PS100 infrared laser altimeter and the Geonics EM31 geophysical electromagnetic induction device. The fields in this dataset are: DAY is Julian day TIME is in seconds after midnight (UTC). LASER is the laser altitude above the snow/ice (metres). A zero reading indicates no return (open water). PITCH is pitch of the system in degrees. ROLL is roll of the system in degrees. COND-A is analogue conductivity from the EM31 (not used). PHASE-A is analogue in-phase response from the EM31 (not used). COND is the estimated depth to seawater (metres) from the EM31-ICE processing module. PHASE is the EM31 in-phase response (expressed as parts per thousand of the primary field). A value of 9.99 indicates the magnetic field was too large to be recorded. SITE LATITUDE LONGITUDE SNOW THICKNESS ICE THICKNESS FREEBOARD a is the electrode spacing. R is the measured resistance. Rho is the apparent conductivity (not true conductivity) = 2 aR. CONDUCTIVITY = 1/Rho.

Metadata record for data from ASAC Project 2295 See the link below for public details on this project. ---- Public Summary from Project ---- Longline fisheries represent a serious threat to the survival of Southern Ocean albatrosses and petrels. During line setting operations seabirds become entangled with baited hooks and are drawn underwater and drown. In the past 10-20 years populations of some species have decreased at an alarming rate and some species are considered to be threatened with extinction. The Antarctic Divisions seabird by-catch program is attempting to minimise mortality in longline fisheries by a multi-faceted approach involving mitigation research on fishing vessels, research on seabirds and initiatives of a semi-political nature. We chartered F/V Assassin for three days to trial a series of line weighting regimes under fishing conditions experienced in the east coast tuna fishery. Sink rates of lines with 52 combinations of swivel weight, bait type and bottom length were recorded. In Mooloolaba they don't use leaded swivels. Therefore it is an unweighted snood. Files Tuncurry_order_of_sets.xls Assassin TDR metadata.xls indicate the factors tested in the experiment, and the order in which they were undertaken. The Tuncurry_order_of_sets.xls file is the order in which the snoods (numbered by regime code) were put out during each line set. Should be read in conjunction with the metadata file. The D1, D2, D3 numbers denote the end of a working day when we downloaded the data from the day's line sets (4 on day 1, 6 on day 2, 5 on day 3). Files assassin summary means.xls assassin summary seconds to depth for analysis.xls assassin_means_to_depth.xls Assassin_time_to_depth_graphs.xls are files summarising the sink rates. The folder Final_data_files contains all the raw time depth recorder files. The fields in these datasets are: Bait type YT - yellowtail, SM - slimy mackerel, SQ - squid, SA - Saury, LYT - Live Yellow Tail, LSM - Live Slimy Mackerel, DYT - Dead Yellowtail, DSM - Dead Slimy Mackerel, DSQ - Dead Squid, DSQ + light/Sau - Dead Squid plus lightstik/Saury, DSQ + light - Dead Squid plus lightstik Bait life status (D - dead, L - live) Swivel weight (grams) Bottom length (metres) Number (n) Standard Deviation Time to depth (seconds) Light stik Side (SB - Starboard, P - Port) Day Replicate Regime (codes are the number of the snood (just a way to keep a track of the treatments)) Depth (metres) TDR Time Depth Recorder (number in each shot represent the individual time depth recorder number that was attached to the snood just near the hook) Taken from the 2008-2009 Progress Report: Progress against objectives: We have consolidated two research streams for pelagic longline fisheries. One is to conduct "conventional" mitigation research, principally focusing on methods to expedite gear sink rates, and the other is to develop an underwater bait delivery system for tuna and swordfish gear. Both streams are dealt with below. The conventional research focuses on operational aspects of gear, and at this stage does not involve seabird avoidance research (this will come later). In the last 12 months I have a) completed a designed experiment on a chartered tuna vessel off Mooloolaba, Queensland, examining the effect of mainline tension (created by use of a line shooter) on the sink rate of baited hooks in the shallow depth ranges; b) a designed experiment in Coquimbo, Chile (as part of Birdlife Internationals Albatross Task Force) examining the effect on initial sink rates of the five branch line deployment methods used by tuna vessels in the southern hemisphere, and c) completed five weeks in Mooloolaba with a chartered fishing vessel and in collaboration with DeBrett's Seafoods and Amerro Engineering, on the R and D of the underwater setting machine. Taken from the 2009/2010 Progress Report: In the past 12 months research work has focused on: a) the development of the underwater bait setting capsule, b) the effects of propeller turbulence on the sink rates of baited tuna hooks, c) the effect of improved line weighting on the catch rates of fish taxa. We have made considerable progress with the underwater setting machine and are intending to complete a "proof-of-concept" experiment with the device in Uruguay this winter/spring. Project "b" was completed on two vessels (one in Chile and one in Australia, as opportunities arose) and a paper was submitted to the Seabird Bycatch Working Group meeting of ACAP in April 2010. Part "c" above was completed in January 2010 and has morphed into a second trial that may show more promise that the first. When that trial has been completed the work will be written up for publication. Taken from the 2010/2011 Progress Report: Public summary of the season progress: Line weighting trials: A trial was completed on the effects of seabird friendly (fast sinking) tuna branch lines on the catch rates of target and non-target fish. No effects on catch rates were detected, clearing the way for test on effectiveness in deterring seabirds. Out of this trial grew a second study, involving weights placed at the hook. This trial probably has more promise than the first, and is currently underway in the Australian tuna fishery. Underwater setter: A prototype version was tested experimentally off Uruguay in the spring of 2010. The experiment revealed the potential of underwater setting to near-eliminate seabird interactions. We are currently finessing the technology with a view to returning to Uruguay (with the finished product) in autumn 2012 to complete the experiment.