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  • 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.

  • The objectives for this project were: The project aims to quantify the patterns of dispersal and survival of newly weaned southern elephant seal pups to provide information on position at sea and foraging behaviour of the pups once they leave Macquarie Island, and to examine how this is related to position at sea and foraging behaviour in the second year. This information will be used to test the hypothesis that first year survival is a consequence of the young animals exploiting different foraging grounds to adults, and that fishing activity on the Campbell Plateau may be a contributing factor. In addition, stable isotope analysis and fatty acid signature analysis will be used to examine differences in foraging behaviour from animals while they are at sea. The raw data from this project is added to the long term database described by the metadata records 'Macquarie Island Elephant Seal Populations 1950-1965', and 'Macquarie Island Elephant Seal Populations 1985 Onwards'. This database has been taken offline, however. A snapshot of the database was taken in January, 1995, and is linked at the provided URL. For access, contact the Australian Antarctic Data Centre. A number of papers have been produced from this project. Some of these papers are included in the reference section below. The data collected for the database is as follows: Seal Number Status (new or resight) Date Location Age Class Status (cow, beachmaster, pregnant cow, dead etc) Sex Weight Length Size Back Fat Flipper Body Water Time Depth Recorder

  • Twenty three juvenile (8-14 months of age) southern elephant seals (Mirounga leonina L.) from Macquarie Island were tracked during 1993 and 1995. Migratory tracks and ocean areas with concentrated activity, presumed to be foraging grounds, were established from location data gathered by attached geolocation time depth recorders. The seals ranged widely (811-3258 km) and foraging activity centred on oceanographic frontal systems, especially the Antarctic Polar Front and bathymetric features such as the Campbell Plateau region. The seals spent 58.6% of their sea time within managed fishery areas while the remainder was spent on the high seas, an area of unregulated fishing. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) areas 58.4.1, 88.2 and especially 88.1 were important and distant foraging areas for these juvenile elephant seals. From fisheries records, diet and the foraging ecology studies of the seals there appears to be little, if any, overlap or conflict between the seals and commercial fishing operations within the regulated commercial areas. However, attention is drawn to the possibility of future interactions if Southern Ocean fisheries expand or new ones commence. Furthermore... The dive duration of 16 underyearling (6-12 months old) southern elephant seals Mirounga leonina during their second trip to sea was investigated using geolocating time depth recorders. Underyearling seals had a lesser diving ability, with respect to duration and depth, than adult southern elephant seals. Individual underyearlings dived for average durations of up to 20.3 minutes and depths up to 416m compared to durations and depths of 36.9 minutes and 589m, respectively for adults. Dive duration was positively related to their body mass at departure, indicating that smaller seals were limited to shorter dive durations, perhaps as a result of their lesser aerobic capacity. All seals often exceeded their theoretical aerobic dive limit (average of 22.1 plus/minus 18.1%). The number of dives exceeding the theoretical aerobic dive limit was not related to mass, suggesting that factors other than mass, such as foraging location or prey availability, may have been responsible for the differences in diving effort. Foraging ability, indicated by the ability of the seals to follow vertically moving prey, was positively related to seal mass, indicating that small mass restricted foraging ability. The shorter dive durations of the smaller seals inferred that they had shallower dive depths in which to search for prey, thus restricting foraging ability. Although foraging ability was restricted by size, foraging success was found to be inversely related to mass, the smaller seals gaining a higher proportion of blubber than larger seals during their foraging trips. Thus, despite smaller seals being restricted to shallower depths and shorter durations, their foraging success was not affected. The fields in this dataset are: Area Perimeter ID Latitude Longitude Time Percent CCAMLR EEZ Season Seal Sex Age (months) Days at Sea Range (km) Bearing (degrees) Sea Surface Temperatures (degrees C) Foraging Areas Departure Mass (kg) At sea mass gain (kg) Rate of mass gain (kg) Survival estimates Length (m) Girth (m) Dives Divers per hour Total Time Diving % trip diving Dive Duration Surface Time Theoretical Aerobic Dive Limit Drift