EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > MAMMALS > CARNIVORES > SEALS/SEA LIONS/WALRUSES
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This is a digital version of the grid reference map used to plot all sightings of Weddell seals in the Vestfold Hills. The point of origin is the same as the original map and each grid cell is numbered with the same numbering scheme. This can be used to plot any data using the same numbering scheme by joining (ArcInfo) or linking (ArcView) records to this coverage's polygon attribute table (pat) through the item GRIDREF. The original map was a 1:100 000 map of the Vestfolds, provided by Harry Burton, with a grid drawn over it. The grid references were given as either six or four figure values on which field scientists are to plot their data. This map has the following Antarctic Division drawing reference number: M/75/05A Some research with John Cox revealed that this grid was drawn up over a map digitised from another map with the following specifications: Scale 1: 100 000 Date: 1958 (reprinted 1972) Projection: Polyconic Published by: Division of National Mapping, Canberra Reference number: NMP/58/084 Data are referenced to a 'grid' of 1 minute spacing in x axis and 30 second spacing in y axis. The point of origin is apparently 68 20 S 77 48 E. There are 45 rows and 47 columns. The 'grid reference' is in fact in geographic coordinates (but using arbitrary units) so the projection of the original map became irrelevant. The procedure adopted to create a new digital grid was as follows: (Carried out in Arc/Info) 1. Generate a coverage using the original 'grid references'. 2. Tics were also generated using the corners of the 'grid reference' system. 3. A new coverage was created with tics at the same locations but given the true latitude/longitude vales. 4. The original coverage was then transformed to the new coverage based on the new tic values. 5. The new coverage was then projected from geographic coordinates to UTM metres. The data locations were then viewed in Arc/Info using a coverage of the coastline supplied by the Mapping Officer, Antarctic Division. This had previously been determined to be in the UTM projection. An offset was clearly visible between the data locations and the coastline. In order to determine whether the offset was more or less uniform, ten locations were plotted from the original data onto the original map using the 'grid'. Finally a manual corrected was made by moving all the data locations by a uniform distance of 508 metres north and 68 metres west. Information from John van den Hoff, February 2019: The grid cells were originally labelled from 1 to 47 along the x axis and 1 to 45 along the y axis. The four digit values in the GRIDREF field of the attribute table are the x value followed by the y value. To avoid confusion between x and y values, the grid was later revised so that the y values were prefixed with a ‘1’ so for example 01 became 101. The GRIDREF_X and GRIDREF_Y fields have the x and y values of the revised grid. This needs to be kept in mind when data is sourced from field books. The map shows the revised grid.
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Results from a February 2007 survey of the Vestfold Hills coastline and offshore islands for used and disused southern elephant seal wallows. The data here are point locations of the wallows, not the extents or boundaries of the wallows. The table below gives the coordinates (decimal degrees) for the elephant seal wallows found, their unofficial names and the wallow status as used or disused at the time of survey. Data were used in the 2018 Vestfold Hills/Davis Station Helicopter map: Wallow name Latitude Longitude Status Hawker Island -68.637360 77.840040 Used Hawker Island -68.634950 77.841310 Used Hawker Island -68.632180 77.841560 Used Mule Island -68.647860 77.825900 Unused Mule Island -68.646650 77.823920 Unused Zappert Point -68.505100 78.081020 Unused Old Wallow -68.598345 77.937185 Used Davis beach -68.577926 77.967032 Used Heidemann Bay -68.592067 77.945325 Used North of station -68.571916 77.971011 Used
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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.
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Southern elephant seals are among the deepest diving of all marine mammals. This study examined physiological and behavioural mechanisms used by the seals to conserve energy while diving and estimated metabolic rate. Data were collected on Time Depth Recorders (TDRs), and stored in hexadecimal format. Hexadecimal files can be read using 'Instrument Helper', a free download from Wildlife Computers (see the provided URL).
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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.
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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.
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This log contains notes and observations of Leopard seals at Mawson, collected between 1979 and 1987. The hard copy of the log has been archived by the Australian Antarctic Division library.
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This file contains a log of biological observations of Weddell Seals and Leopard Seals taken at Mawson Station between 1974 and 1979. The hard copy of the log has been archived by the Australian Antarctic Division library.
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Elephant seals use a suite of physiological and behavioural mechanisms to maximise the time they can be submerged. Of these hypo-metabolism is one of the most important, so this study quantified maximum O2 consumptions relative to dove depth and swim speed. From the abstract of the referenced paper: Heart rate, swimming speed, and diving behaviour were recorded simultaneously for an adult female southern elephant seal during her postbreeding period at sea with a Wildlife Computers heart-rate time depth recorder and a velocity time depth recorder. The errors associated with data storage versus real-time data collection of these data were analysed and indicated that for events of short duration (i.e., less than 10 min or 20 sampling intervals) serious biases occur. A simple model for estimating oxygen consumption based on the estimated oxygen stores of the seal and the assumption that most, if not all, dives were aerobic produced a mean diving metabolic rate of 3.64 mL O2 kg-1, which is only 47% of the field metabolic rate estimated from allometric models. Mechanisms for reducing oxygen consumption while diving include cardiac adjustments, indicated by reductions in heart rate on all dives, and the maintenance of swimming speed at near the minimum cost of transport for most of the submerged time. Heart rate during diving was below the resting heart rate while ashore in all dives, and there was a negative relationship between the duration of a dive and the mean heart rate during that dive for dives longer than 13 min. Mean heart rates declined from 40 beats min-1 for dives of 13 min to 14 beats min-1 for dives of 37 min. Mean swimming speed per dive was 2.1 m s-1, but this also varied with dive duration. There were slight but significant increases in mean swimming speeds with increasing dive depth and duration. Both ascent and descent speeds were also higher on longer dives. Data were collected on Time Depth Recorders (TDRs), and stored in hexadecimal format. Hexadecimal files can be read using 'Instrument Helper', a free download from Wildlife Computers (see the provided URL). Data for this project is the same data that was collected for ASAC projects 769 and 589 (ASAC_769 and ASAC_589).
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To quantify the post-breeding movements of adult female Antarctic females (Arctocephalus gazella) we tracked females using Biotrack GLS (geolocation) data loggers. Females were captured towards the end of the lactation period (March/April) and the GLS tag, affixed to a Dalton flipper tag, was deployed in the trailing edge of the left or right foreflipper. Tags were generally retrieved just prior to or after giving birth the following season. Data files were extracted from the tags using BASTrak software. .lig - light data .tem - temperature data .act - activity data Metadata for each individual include: Site, year, GLS ID, sex, age, deployment site, lat and long of deployment site, flipper tag number, deployment and retrieval times (GMT).