To quantify the dietary preferences and trophic level consumption of post-breeding adult female Antarctic fur seals (Arctocephalus gazella), we analysed the carbon:nitrogen composition of whiskers and blood samples from the females. Females were captured towards the end of the lactation period (March/April) and whiskers and a blood sample were collected at this time. Females were generally recaptured just prior to or after giving birth the following season and a further whisker and blood sample were collected at this time. Metadata for each individual include: Site, GLS ID, year, flipper tag number, season, sampling date, tissue type, whisker segment number, cumulative length along whisker of the segment, d15N, d13C, percentage N, percentage C and CN ratio.

Antarctic Fur Seals from Heard Island fed mainly on fish, but the prey species changed both seasonally and inter-annually. The majority of prey were pelagic myctophids characteristic of deep oceanic water, and were generally taken in autumn and winter. The only other fish taken in significant numbers was Champsocephalus gunnari which was mostly taken from late winter through early autumn when it was co-dominant in the diet with the Krefftichthys anderssoni. Males and females foraged in different localities and in different parts of the water column. Males foraged mainly to the south of Heard Island in winter usually diving deep by day, feeding on scattering layers. In summer males also fed on the shelf, presumably to the north and east of Heard Island on K. anderssoni at shallow depths primarily at night. Although diet studies provided little evidence of feeding on crustaceans, diving data indicate that some males may travel to Antarctic waters in winter to feed on krill. The fields in this dataset are: Months Species Scats Time foraging Number of Dives Time Submerged (minutes) Mean Dive Duration (minutes) Maximum Depth (metres)

This database is a compendium of histories of known age seals (Weddell and Southern elephant) from observations across the Southern Ocean but focussed on Macquarie Island, Marion Island, Heard Island, Mawson and the Vestfold Hills. At Macquarie Island 1000 seals were weighed per annum between 1993-2003 at birth and individually marked with two plastic flipper tags in the inter-digital webbing of their hind flippers. These tagged seals were weighed again at weaning, when length, girth, fat depth, and flipper measurements were made. Three weeks after weaning 2000 seals were permanently and individually marked by hot-iron branding. Recaptures and re-weighings of these known aged individuals were used to calculate growth and age-specific survival of the seals. Similar data were collected from elephant seals between 1950 and 1965 when seals were individually marked by hot-iron branding. Mark-recapture data from these cohorts were used to assess the demography of the declining population. Length and mass data were also collected for these cohorts and were used, for the first time, to assess the growth of individual seals without killing them. At Marion Island all the elephant seals have been individually marked with two plastic flipper tags in their rear flippers. Recaptures of these seals were used to compare survival at Marion and Macquarie Islands. At Heard Island, seals were branded between 1949-1953. Seal length was measured in feet and inches. Recaptures of seals were made up until 1955, and growth and age-specific survival was calculated. Survival data from Heard Island were compared with concurrent data from Macquarie Island. The database was held by the Australian Antarctic Data Centre, but was taken offline due to maintenance problems. A snapshot of the database was taken in June 2018 and stored in an access database. This work was completed as part of ASAC project 90.

A Cape-wide census of Antarctic fur seal (Arctocephalus gazella) pups (live and dead) occurs every year once pupping is over. The census occurs in the last days of December, on a day when conditions and visibility are favorable. Cape Shirreff is located on Livingston Island, in the South Shetlands off the Antarctic Peninsula.

To quantify the dietary preferences and trophic level consumption of post-breeding adult female Antarctic fur seals (Arctocephalus gazella), we analysed the carbon:nitrogen composition of whiskers and blood samples from the females. Females were captured towards the end of the lactation period (March/April) and whiskers and a blood sample were collected at this time. Females were generally recaptured just prior to or after giving birth the following season and a further whisker and blood sample were collected at this time. Metadata for each individual include: Site, GLS ID, year, flipper tag number, season, sampling date, tissue type, whisker segment number, cumulative length along whisker of the segment, d15N, d13C, percentage N, percentage C and CN ratio.

Publication of these results is currently in progress with the Journal of Animal Ecology. Summary 1.An efficient method of describing change in Antarctic marine ecosystems is long-term monitoring of land-breeding marine predators. High-level predators are used to index the state of environment on the notion that perturbations in the ecosystem will affect their diet, reproductive performance and other demographics. For this purpose, Weddell seals breeding at the Vestfold Hills have been marked and re-sighted for the past 28 years (1973 - 2000). 2.Successful reproduction requires considerable energetic resources. The difference between rates of conception and rates of parturition suggests pregnant females abort reproductive attempts when their energy stores are low. In this way, annual rates of reproduction (i.e. parturition) are a measure of foraging efficiency. 3.Previous attempts to estimate Weddell seal reproduction have been biased by different rates of re-sighting breeding and non-breeding females. We used multistate mark and re-sight models to account for this and other variables when estimating reproductive rate. 4.The amplitude of temporal variation was much greater for reproduction than for survivorship, indicating that parous (breeding) females maximised survival by reproducing less. This strategy could be successful in fluctuating environments because seals live longer and experience more reproductive occasions. 5.The population had low reproductive rates from 1983 to 1985 and throughout the 1990s. In those years, potential recruitment into breeding groups was reduced to 50 - 60 % of the cohort before viable pups were even born. 6.Even in years of low reproductive rate, typically half (52%) of the breeding females produced pups. It seemed that individuals differed in their foraging success and thus body condition and / or their functional response to this. 7.There was no evidence for costs of reproduction. We infer that the seals responded to environmental conditions prior to parturition, as opposed to proceeding with reproduction when inadequately resourced and depleting energy resources such that they had lower probability of surviving or reproducing the following year. 8.Synthesis and applications: This study demonstrates a method of estimating reproductive rate that overcomes bias inherent in traditional methods. Estimated in this way, we propose that reproductive rate is the best indicator of the state of marine ecosystems that can be indexed for Weddell seals. The fields in this dataset are: Year Standard Error Upper confidence interval Lower confidence interval Breeding probability Upper error bar Lower error bar

Taken from the abstract of the referenced papers: Maternal attendance behaviour was studies in Antarctic (Arctocephalus gazella) and subantarctic fur seals (Arctocephalus tropicalis) which breed sympatrically at subantarctic Macquarie Island. Data on attendance were obtained using telemetric methods. Both species undertook two types of foraging trips: overnight foraging tips which were of less than 1 day duration and occurred exclusively overnight, and extended foraging trips which lasted longer than 1 day. The mean duration of overnight foraging trips was 0.43 and 0.39 days, while the duration of extended foraging trips was 3.6 and 3.8 days in A. gazella and A. tropicalis, respectively. The duration of overnight and extended foraging trips did not differ significantly between species. Two types of shore attendance bouts that differed in duration were also observed in these species. Short attendance bouts lasted less than 0.9 days, while long attendance bouts lasted longer than 0.9 days. Short attendance bouts lasted 0.4 and 0.5 days, while long attendance bouts lasted 1.6 and 1.7 days in A. gazella and A. tropicalis, respectively, and did not differ significantly between species. The most significant differences between the attendance behaviour of both species was in the percentage of foraging time allocated to overnight foraging trips (15% and 25% in A. gazella and A. tropicalis, respectively), and the percentage of time spent ashore (30% and 38% in A. gazella and A. tropicalis, respectively). The nearness of pelagic waters to Macquarie Island is considered to be the main reason that lactating females are able to undertake overnight foraging trips. These trips may be used by females as a means of optimising the costs of fasting and nursing ashore. Females may be able to save energy by only nursing pups when milk transfer efficiencies are high, and reduce the time and energy costs of fasting ashore when milk transfer efficiency is low. Of the female A. gazella that still carried transmitters at the end of lactation, 83% continued regular attendance for between 21 and 150 days post-lactation (when data collection ceased). Overwintering of A. gazella females at breeding sites has not been previously reported in other populations. Breeding colonies of the Antarctic fur seal Arctocephalus gazella on Heard Island (53.18S, 73.5E) are situated on the sheltered northern and eastern coasts on flat vegetated terrain near streams and pools. Pupping in the 1987/88 summer began on 21 November, with 90% of births in 26 d. The median birth date was 11 December. Pup counts at Heard Island made in seven breeding seasons from 1962/63 to 1987/88 show an exponential rate of increase of 21%, which may be inflated due to undercounting in early years. The total of 248 births in 1987/88 represents an exponential increase of 37% since the previous year, but pups may have been undercounted then. Based on the number of pups born, the breeding population is estimated at 870-1,120. During the breeding season, the largest number of animals ashore was 835. Many non-breeding fur seals began hauling out from early January and 15,000 animals were estimated to be ashore by late February, a far larger number than expected from the size of the breeding population. Both the breeding and non-breeding components of the population may be augmented by immigration. The source of immigrants may be undiscovered breeding colonies of this species in the northwestern sector of the Kerguelen Archipelago or the concentration at South Georgia. Further censuses are required at Heard Island to monitor the population growth.

This is a polygon dataset digitised from a 1982-1984 Frozen Sea Expedition grid map (attached) showing locations where Weddell seals were recorded in the Rauer Group region, Prydz Bay, Antarctica. Weddell seal distribution data were mapped by members of the Oceanic Research Foundation Ltd. in collaboration with Harry Burton and Rhys Puddicombe (ANARE). This work was undertaken during the Frozen Sea Expedition to Prydz Bay which occurred between 1982-1984 and during which the expedition schooner 'Dick Smith Explorer' wintered in the Rauer Group. Locations of seal occurrence were marked on a base map of the Rauer Group on which a grid had been drawn. Data were recorded as 'Late Autumn /early Winter most common seal locations (July to September)' and 'Known pupping locations (October to December)'. The locations as highlighted on the map were digitised by the AADC in 2025 and are attached to this record as polygon data in a GeoPackage.

The populations of fur seals on Australia's two subantarctic islands were exterminated by uncontrolled sealing in the 19th century. Only in the latter half of the 20th century have populations commenced recovering. This project provides key information on the status and trends of recovering fur seal populations in the Southern Ocean, including information on the distribution of foraging effort, food and energy requirements, oceanographic determinants of demographic performance, ecological interactions with commercial fisheries, the extent, trends, processes and implications of hybridisation at Macquarie Island, and the status and trends in numbers of the threatened subantarctic fur seal. This dataset represents ARGOS tracking data of fur seals from Macquarie Island during 1997-1999. The tracking data are comprised of 28 data profiles. Taken from the abstract of the referenced paper: Antarctic Arctocephalus gazella and subantarctic Arctocephalus tropicalis fur seals breed sympatrically at Macquarie Island. The two species have different lactation strategies, the former rearing its pup in 4 months and the latter taking 10 months. The diet and at-sea foraging behaviour of these sympatric species was compared during the austral summer period when their pup rearing period overlapped. The prey of the two fur seal species was very similar, with fish dominating the diet. Themyctophid, Electrona subaspera, was the main prey item (93.9%) in all months of the study. There were no major differences in the diving behaviour between species. Both species foraged north of the island parallel to the Macquarie Ridge. Foraging activity was concentrated at two sites: (i) within 30 km north of the island; and (ii) at 60 km north. Most locations for overnight foraging trips were within 10 km of the colonies. The different lactation strategies of A. gazella and A. tropicalis allowed for flexibility in foraging behaviour. At Macquarie Island, the local marine environmental conditions have resulted in similar foraging behaviour for both species.

During the winter and spring of 2002, underwater calling rates were measured near mid-day on an opportunistic basis at 7 breeding sites and, at two breeding sites, over 24 hour periods once a month. The data were analysed with respect to reproductive season (early ice formation, prebreeding, pupping and mating) and if the recordings were made when it was dark or twilight/light. Taken from the abstract of the paper referenced below: Underwater vocalisation monitoring and surveys, both on ice and underwater, were used to determine if Weddell seals (Leptonychotes weddellii) near Mawson Station, Antarctica, remain under the fast ice during winter within close range of breeding sites. Daytime and nighttime underwater calling rates were examined at seven breeding sites during austral winter and spring to identify seasonal and diel patterns. Seals rarely hauled out at any of the sites during winter, although all cohorts (adult males, females, and juveniles) were observed underwater and surfacing at breathing holes throughout winter (June-September) and spring (October-December). Seal vocalisations were recorded during each sampling session throughout the study (n=102 daytime at seven sites collectively, and n=5 24-h samples at each of two sites). Mean daytime calling rate was low in mid-winter (July) (mean = 18.9 plus or minus 7.1 calls per minute) but increased monthly, reaching a peak during the breeding season (November) (mean = 62.6 plus or minus 15.7 calls per minute). Mean nighttime calling rate was high throughout the winter and early spring (July-October) with mean nocturnal calling rate in July (mean = 61.8 plus or minus 35.1 calls per minute) nearly equal to mean daytime calling rate in November (during 24-h daylight). Reduced vocal behaviour during winter daylight periods may result from animals utilising the limited daylight hours for nonvocal activities, possibly feeding. The following study sites were among those used in this project (provided by Phil Rouget): Forbes site (identified as Site 6 in the paper) is located at Forbes Glacier (approx. 0.5 km to the west of the glacier tongue and approximately 200 meters offshore of the mainland). (67 degrees 35.256 minutes S, 62 degrees 16.756 minutes E) Kista site is located in the middle of Kista Strait (site 7 in the Marine Mammal Science paper). (67 degrees, minutes 33.840 S, 62 degrees 47.402, minutes E) SPA site was our site located just west of the western boundary of the SPA which itself is located west of Mawson and east of Forbes Glacier. (Site 2 in Marine Mammal Science paper). (67 degrees 35.179 S, 62 degrees 25.425 minutes E) McDonald Islands (or Rocks) was the site located North/NorthWest of Kista Strait, as it is named so on the Framens Mtn. Nautical Chart. From memory, it was approximately 12 km north/north west of Mawson Station. (This was site 5 in the Marine Mammal Science paper). (67 degrees 29.414 minutes S, 62 degrees 41.011 minutes E) Stewart Rocks (also named Sewart Rocks on an alternative map) is located due north of Mawson Station, also by about 12 km. (East of McDonald site, and North East of Kista). This was site 4 in the Marine Mammal Science paper. (67 degrees 29.933 minutes S, 62 degrees 51.765 minutes E) Anderson Rocks is an extensive group of rocky islets west of Auster Island (approximately 6-7 km offshore). This was site 3 in the Marine Mammal Science paper. (67 degrees 26.445 minutes S, 63 degrees 25.414 minutes E) SEAL MO was located just north of Macey Hut by about 2 km. This was site 1 in the Marine Mammal Science paper. (67 degrees 23.399 minutes S, 63 degrees 47.977 minutes E) Aside from SEAL MO and SPA, the names from all these sites are indicated in the Framnes Mountain Chart. An image showing the locations of the fields sites is also part of the download file. The fields in this dataset are: Site Period Day Calling rate photoperiod Sun time