Metadata record for data from ASAC Project 257 See the link below for public details on this project. From the abstracts of some of the referenced papers: Anatomical and physiological studies of southern elephant seals (Mirounga leonina), particularly in the post-natal period, raise questions of relative musculature growth, control of metabolism, circulation and temperature regulation, which could be important in our understanding of these processes in mammals and of their contribution to adaptation to environmental extremes. The diving behaviour of 14 adult southern elephant seals was investigated using time depth recorders. Each of the seals performed some dives that were longer than its theoretical aerobic dive limit. Forty-four percent of all dives made by post-moult females exceeded the calculated limit compared with 7% of those made by postbreeding females and less than 1% of those made by adult males. The extended dives displayed characteristics that suggested they were predominantly foraging dives, although some were apparently rest dives. Dives longer than the calculated aerobic limits often occurred in bouts; the longest consisted of 63 consecutive dives and lasted 2 days. Postmoult females performed longer bouts of extended dives than postbreeding females. Extended surface periods (longer than 30 min) were not related to the occurrence of extended dives or bouts of extended dives. The possible physiological mechanisms that permit such prolonged continuous dives are discussed. Southern elephant seals may increase the aerobic capacity of dives by lowering their metabolism to approximately 40% of the resting metabolic rate on long dives. There is substantial interseal variability in the methods used to cope with long dives. Some animals appear to use phsyiological strategies that allow them to prolong the time available to them at the bottom of a dive, while others use alternative strategies that may limit the time available at the bottom of their dives. Fourteen time-depth-temperature recorders were recovered from adult southern elephant seals (Mirounga leonina) returning to Macqaurie Island to breed or moult. The resulting temperature/depth profiles indicated that all four males spent most of their time in waters lying over the Antarctic Continental Shelf, whereas only one of the ten females spent any time there. Five of the females foraged just off the Antarctic Continental Shelf, and the other five remained near the Antarctic Polar Front. 1) Mark-resight data were analysed for thirteen cohorts from a declining population of southern elephant seals branded at Macquarie Island between 1951 and 1965. 2) First year survival was essential stable during the 1950s at about 46% for females and 42% for males. There was a dramatic fall in first year survival during the 1960s, declinging to less than 2% for both sexes in 1965. Post-year-1 survival did not change between the 1950s and the 1960s. 3) Comparisons with a stable population of southern elephant seals at South Georgia indicated that both first year and adult survival were lower in the Macquarie Island population. There were no changes in the age at first breeding of the Macquarie Island seals during the study, but this was on average 1 year later than at South Georgia. 4) It is hypothesised that the current decline in elephant seal numbers at several of their major breeding islands is due to the populations returning to pre-sealing levels after they had risen to abnormally high levels with the end of commercial exploitation early this century. 5) Possible tests of the hypothesis include studying the diet and foraging behaviour of southern elephant seals to gain an understanding of the predator-prey relationships, continuing to census the Macquarie Island population to determine if the population levels out at around the estimated pre-sealing levels, and monitoring northern elephant seal populations which were also severely exploited but are currently increasing rapidly.

Metadata record for data from ASAC Project 2695 See the link below for public details on this project. Variations in the winter extent of sea ice are thought to have profound effects on biological productivity, such as algal growth and the reproduction of Antarctic krill, with subsequent flow-on effects through the food web. This pilot study aims to measure the winter foraging patterns of Weddell seals (Leptonychotes weddellii) as a first step in investigating their role in the winter sea-ice zone. Our specific objectives are to: 1. Obtain satellite tracks from a sample of adult female Weddell seals 2. Collect diving behaviour (dive depth, duration and frequency) from a sub-set of these seals 3. Collect high precision water temperature data from a subset of these seals These data will enable us to assess the feasibility of including Weddell seals as a candidate species in a long-term study of winter sea-ice and predator performance. This project has now been merged into project number 2794 (ASAC_2794). It also contains data collected as part of project 1171 (ASAC_1171). The download file contains 13 Access Databases containing data from this project. An excel spreadsheet summarising the databases is also included. The data have also been loaded into the Australian Antarctic Data Centre's ARGOS tracking database. The database can be accessed at the provided URL.

Metadata record for data from ASAC Project 2794 See the link below for public details on this project. Public: This study will use innovative technology to measure the winter spatial foraging patterns and net energy gain of adult female elephant seals (and potentially Weddell seals), while simultaneously providing high-resolution data on the physical nature of the water column in which the seals live. By combining biological and physical data with satellite derived sea-ice information, this study will improve our understanding of predator foraging success (and therefore mechanisms which regulate population trajectories) and provide physical oceanographers with fundamental data on the importance mechanisms that determine the winter ice and bottom water formation that under-pin the Antarctic marine ecosystem. Project objectives: The extent and nature of Antarctic winter sea ice is thought to have profound impacts on biological productivity, the recruitment of Antarctic krill, and the flow-on effects through the Antarctic marine food web. 1. Winter sea-ice formation is also hypothesised to play an important, yet highly-variable role in ocean circulation patterns through the production of cold, dense winter bottom water. 2. The mechanisms determining the inter-annual variation in winter ice formation are poorly understood, as are the complex feedback processes involved, but they are nonetheless recognised as being vulnerable to human-induced climate change. 3. Given the dynamically-linked nature of winter-ice and biological productivity, long-term climatic changes will have broad scale influences on Antarctic biota. This study will use innovative technological developments to quantify the response of one of the major Antarctic marine predators, the southern elephant seal (Mirounga leonina), to inter-annual variation in winter ice conditions. We will measure the winter spatial foraging patterns and net energy gain of adult female elephant seals while simultaneously providing high-resolution data on the physical nature of the water column in which the seals are living. The combination of these biological and physical data with satellite-derived sea-ice information will relate variation in the winter-ice to broad scale biological production through the foraging success (maternal investment and therefore demographic performance) of a top Antarctic marine predator, as well as providing physical oceanographers with fundamental data on the important mechanisms that determine the winter ice and bottom water formation that under-pin the Antarctic marine ecosystem. The specific objectives are to: 1. Measure the foraging performance of the seals in terms of spatially-specific net energy gain while at sea, in relation to intra- and inter-annual variation in sea-ice and oceanic processes. 2. Use newly-developed (and tested) animal-borne satellite-linked Conductivity-Temperature-Depth Satellite Relay Data Loggers (CTD-SRDLs) to provide oceanographic quality data on local physical characteristics (temperature and salinity). 3. Record fine-scale foraging parameters (dive depth, duration, swimming speed) using "Dead-Reckoning" Data Loggers (DRDLs) and feeding events using Stomach Temperature Sensors (STSs). 4. Integrate these data collected in years and regions of different winter ice extent and conditions. 5. Assess diet during the winter months using stable isotope and fatty acid signature analysis. 6. Combine the biological and physical information to refine current models of predator performance based on annual climatic features. These models will be used to examine a range of climate-change scenarios, initially for elephant seals but with a view to broadening the species application at a later stage. Taken from the 2008-2009 Progress Report: Progress against objectives: Due to logistic constraints, no satellite telemetry was conducted at Casey or Macquarie Island this year, but preliminary surveys of the region were conducted for both elephant and Weddell seals (see report for 2753). However we did deploy CTD satellite tags on elephant seals at Isles Kerguelen and Elephant Island to contribute to the IPY MEOP program. These animals either traversed the Southern Ocean to forage over the Antarctic continental shelf, or remained very close to their breeding island, indicating that even within a population there are markedly different foraging strategies. Taken from the 2010-2011 Progress Report: Public summary of the season progress: Due to pre-departure accident for one of the field team leaders we were unable to reach Casey this year to complete that component of the program. Forty CTD satellite tags were successfully deployed at Vestfold Hills in January and February 2011. These tags are currently still transmitting from foraging locations along the Antarctic continental shelf and the ice edge. Project 2695 (ASAC_2695) was incorporated into this project. An Access database containing data from this project is available for download at the provided URL. The data have also been loaded into the Australian Antarctic Data Centre's ARGOS tracking database. The database can be accessed at the provided URLs.