Some mammalian and avian species alter their vocal communication signals to reduce masking by background noises (including conspecific calls). A preliminary study suggested that Weddell seals (Leptonychotes weddellii) increase the durations of some underwater call types when overlapped by another calling seal. The present study examined the durations and overlapping sequences of Weddell seal calls recorded in Eastern Antarctica. The calling rate, call type (13 major categories), total duration, numbers of elements per call, and overlapping order of 100-200 consecutive calls per recording location were measured. In response to increased conspecific calling rates, the call durations and numbers of elements (within repeated-element call types) did not change or became shorter. Calls that were not overlapped were 3.8 plus or minus 6.1 s long, the first call in a series of overlapped calls was 14.4 plus or minus 15.7 s and subsequent calls in an overlapping series were 6.5 plus or minus 10.3 s. The mean durations of non-overlapped and overlapped calls matched random distributions. Weddell seals do not appear to be adjusting the durations or timing of their calls to purposefully avoid masking each others' calls. The longer a call is, the more likely it is to overlap another call by chance. An implication of this is that Weddell seals may not have the behavioural flexibility to reduce masking by altering the temporal aspects of their calls or calling behaviours as background noises (natural and from shipping) increase.

Metadata record for data from ASAC Project 2179 See the link below for public details on this project. Taken from a progress report of the project written in 1998: 60 terrestrial sediments have been taken from Wilkes and Thala Valley tip, with control sites at Robinsons Ridge and Jacks Donga. 50 marine sediments have been taken from the bay offshore from Thala Valley tip. 116 fresh and marine waters have been taken from the fresh water stream flowing through the Thala Valley tip, the tip/sea interface, and the nearshore marine offshore from Thala Valley tip and control sites. Formal integration of these data into a GIS is underway. These data have not been archived until 2012, hence the only data available were sourced from publications arising from the project.

Access database containing biological and environmental data collected by the Australian Antarctic Division, Human Impacts Benthic Biodiversity group.

This terrestrial dataset was collected at Ursula Harris’s behest by Craig Hamilton and a Naval Survey team on 09 January 2018 when sea conditions prevented the team from taking bathymetric measurements. This survey was intended to fill gaps in the existing Mawson Station survey data and includes 29 previously unrecorded features comprised of bollards, HF towers, flagpoles, masts, antennae, ionosonde transmitter and receiver, the Mawson Signpost and the Douglas Mawson Bust.

The dataset contains boundaries of Cape petrel nesting areas at numerous breeding sites on islands off the Vestfold Hills, Antarctica. Boundaries of nesting sites were obtained from aligning ground observations and photographs from land or the sea-ice adjacent to the breeding sites onto maps of islands in the region. The observations were made and the photographs taken between 18 and 30 November 2017. Marcus Salton and Kim Kliska made the ground observations, took the photographs and delineated the GIS boundaries representing the nesting areas. The data is a polygon shapefile with each polygon designated Type A or Type B. Type A indicates nests present. Type B indicates this area was searched and no nests were present. Also included are three images showing the Type A polygons and the associated nest counts. Please refer to the Seabird Conservation Team Data Sharing Policy for use, acknowledgement and availability of data prior to downloading data.

Adelie colony boundaries at Bechervaise Island were mapped by Matthew Pauza on the 21 Dec 2016. Subcolonies were mapped by circumnavigating the perimeter on foot while carrying a Garmin GPS (Etrex30) to record the track. When mapping the perimeter of the subcolonies a buffer distance of approximately 2.5 meters was maintained between the mapper and the breeding birds. This buffer distance was reduced by .5m to between 2m in the final shapefiles. Please refer to the Seabird Conservation Team Data Sharing Policy for use, acknowledgement and availability of data prior to downloading data.

This file contains a log of biological observations of Pintardo Petrels taken at Mawson Station between 1972 and 1988. The hard copy of the log has been archived by the Australian Antarctic Division library.

INDICATOR DEFINITION Count of all adult females, fully weaned pups and dead pups hauled out on, or close to, the day of maximum cow numbers, set for October 15. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION Elephant seals from Macquarie Island are long distance foragers who can utilise the Southern Ocean both west as far as Heard Island and east as far as the Ross Sea. Thus their populations reflect foraging conditions across a vast area. The slow decline in their numbers (-2.3% annually from 1988-1993) suggests that their ocean foraging has been more difficult in recent decades. Furthermore, interactions with humans are negligible due to the absence of significant overlap in their diet with commercial fisheries. This suggests that changes in 'natural' ocean conditions may have altered aspects of prey availability. It is clear that seal numbers are changing in response to ocean conditions but at the moment these conditions cannot be specified. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial Scale: Five beaches on Macquarie Island (lat54 degrees 37' 59.9' S, long 158 degrees 52' 59.9' E): North Head to Aurora Point; Aurora Point to Caroline Cove; Garden Cove to Sandy Bay; Sandy Bay to Waterfall Bay; Waterfall Bay to Hurd Point. Frequency: Annual census on 15th October Measurement Technique: Monitoring the Southern Elephant Seal population on Macquarie island requires a one day whole island adult female census on October 15 and a daily count of cow numbers, fully weaned pups and dead pups on the west and east isthmus beaches throughout October. Daily cow counts during October, along the isthmus beaches close to the Station, provide data to identify exactly the day of maximum numbers. The isthmus counts are recorded under the long-established (since 1950) harem names. Daily counts allow adjustment to the census totals if the day of maximum numbers of cows ashore happens to fall on either side of October 15. Personnel need to be dispersed around the island by October 15 so that all beaches are counted for seals on that day. This has been achieved successfully for the last 15 years. On the day of maximum haul out (around 15th October) the only Elephant seals present are cows, their young pups and adult males. The three classes can be readily distinguished and counted accurately. Lactating pups are not counted, their numbers are provided by the cow count on a 1:1 proportion. The combined count of cows, fully weaned pups and dead pups provides an index of pup production. The count of any group is made until there is agreement between counts to better than +/- 5%. Thus there is always a double count as a minimum; the number of counts can reach double figures when a large group is enumerated. The largest single group on Macquarie Island is that at West Razorback with greater than 1,000 cows; Multiple counts are always required there. RESEARCH ISSUES Much research has been done already to acquire demographic data so that population models can be produced. Thus there will be predicted population sizes for elephant seals on Macquarie Island in 2002 onwards and the annual censuses will allow these predictions to be tested against the actual numbers. The censuses are also a check on the population status of this endangered species. LINKS TO OTHER INDICATORS

This file contains a log of observations collected in the Casey region between 1972 and 1988. Observations were made of Adelie penguins. The hard copy of the log has been archived by the Australian Antarctic Division library.

Observations of the sea ice near Mawson were carried out in 1980, concentrating on the thickness of the ice at several points, and the accumulation and ablation of snow/ice cover on the ice. The ablation measurements were carried out by laying 23 ablation stakes out in two fields - a set of eight stakes in a straight line, and a set of 15 in a triangle. Results from both sets of observations were recorded in a log book, currently archived at the Australian Antarctic Division.