IMAS Metadata Catalogue
ISOMOVE: Antarctic fur seal stable isotopes and tracking data
This dataset contains stable isotope and tracking data from adult female Antarctic fur seal collected at three breeding colonies across the Southern Ocean:
• Marion Island (2008–2018)
• Bird Island, South Georgia (2008–2012)
• Cape Shirreff, South Shetland Islands (2008–2012)
The dataset includes:
• Stable isotope data from whole blood and whiskers
• Compound-specific amino acid isotope data (δ¹⁵NAA) from whole blood
• GLS-derived tracking and environmental data
Samples were collected from adult female seals captured between February and April prior to winter migration. Whole blood samples provide dietary information integrated over approximately 2–3 months, while sequential whisker sections provide longer-term isotopic records spanning multiple years.
Bulk stable isotope values (δ¹³C and δ¹⁵N) and compound-specific isotope analysis of amino acids (CSIA-AA) provide information on trophic ecology and foraging habitat across multiple temporal scales, from recent feeding behaviour to multi-year dietary histories recorded in whiskers.
The dataset also includes light-based geolocation (GLS) tracking data from adult females equipped with geolocator loggers during the inter-breeding migration period. Tracking variables include timestamps (GMT), estimated geographic positions (latitude and longitude), uncertainty metrics, and associated environmental variables such as sea surface temperature (SST) and absolute dynamic topography (ADT), where available.
Simple
Identification info
- Date (Publication)
- 2026-03-17T00:00:00
Identifier
- Title
- Information and documentation - Digital object identifier system
- Citation identifier
- ISO 26324:2012
- Code
- 10.25959/64A7-FW78
- Codespace
- doi.org
- Description
- Digital Object Identifier (DOI)
Principal investigator
Principal investigator
Collaborator
- Purpose
- The purpose of this dataset is to investigate spatial, temporal, and individual variation in the trophic ecology and movement ecology of Antarctic fur seals, and to assess their role as sentinels of environmental change in Southern Ocean ecosystems.
- Status
- Completed
Principal investigator
Institute for Marine and Antarctic Studies - Lea, Mary-Anne
University of Tasmania
Tasmania
Australia
Point of contact
Institute for Marine and Antarctic Studies - Walters, Andrea
University of Tasmania
Tasmania
Australia
Point of contact
Institute for Marine and Antarctic Studies - Friscourt, Noémie
University of Tasmania
Tasmania
Australia
- Topic category
-
- Biota
Extent
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W
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Temporal extent
- Time period
- 2008-01-01 2012-12-31
- Maintenance and update frequency
- Irregular
- Keywords (Theme)
-
- stable isotopes
- whiskers
- blood
- Keywords (Taxon)
-
- Antarctic fur seal
- Arctocephalus gazella
- Global Change Master Directory Earth Science Keywords, Version 8.5
Resource constraints
- Use limitation
- Data, products and services from IMAS are provided "as is" without any warranty as to fitness for a particular purpose.
Resource constraints
- Other constraints
- This dataset is the intellectual property of the University of Tasmania (UTAS) through the Institute for Marine and Antarctic Studies (IMAS).
Resource constraints
- Linkage
-
https://licensebuttons.net/l/by-nc/4.0/88x31.png
License Graphic
- Title
- Creative Commons Attribution-NonCommercial 4.0 International License
- Alternate title
- CC-BY-NC
- Edition
- 4.0
- Website
-
https://creativecommons.org/licenses/by-nc/4.0/
License Text
- Other constraints
- Cite data as: Friscourt, N., Lea, M.-A., & Walters, A. (2026). ISOMOVE: Antarctic fur seal stable isotopes and tracking data [Data set]. Institute for Marine and Antarctic Studies. https://doi.org/10.25959/64A7-FW78
- Language
- English
- Character encoding
- UTF8
- Supplemental Information
- Friscourt, N., M. A. Lea, Y. Cherel, S. Wotherspoon, E. A. Brewer, W. C. Oosthuizen, P. J. N. de Bruyn, M. Wege, M. E. Goebel, P. N. Trathan, and A. Walters. 2024. Seasonal and ocean basin-scale assessment of amino acid δ15N trends in a Southern Ocean marine predator. Marine Ecology Progress Series 747:151-169. https://doi.org/10.3354/meps14699 Walters, A., M. Hindell, M. E. Goebel, M. N. Bester, P. N. Trathan, W. C. Oosthuizen, and M.-A. Lea. 2020. Southern Ocean isoscapes derived from a wide-ranging circumpolar marine predator, the Antarctic fur seal. Ecological Indicators 118. https://doi.org/10.1016/j.ecolind.2020.106694
Content Information
- Content type
- Physical measurement
Identifier
- Code
- Nitrogen stable isotope
- Name
- Carbon stable isotope
- Name
- Per mill
Identifier
- Code
- Carbon stable isotope
- Name
- Per mille
Distribution Information
- Distribution format
-
- CSV
- OnLine resource
- Browse and download available data files
- OnLine resource
-
Associated publication
Walters, A., M. Hindell, M. E. Goebel, M. N. Bester, P. N. Trathan, W. C. Oosthuizen, and M.-A. Lea. 2020. Southern Ocean isoscapes derived from a wide-ranging circumpolar marine predator, the Antarctic fur seal. Ecological Indicators 118. https://doi.org/10.1016/j.ecolind.2020.106694
- OnLine resource
-
Associated publication
Friscourt, N., M. A. Lea, Y. Cherel, S. Wotherspoon, E. A. Brewer, W. C. Oosthuizen, P. J. N. de Bruyn, M. Wege, M. E. Goebel, P. N. Trathan, and A. Walters. 2024. Seasonal and ocean basin-scale assessment of amino acid δ15N trends in a Southern Ocean marine predator. Marine Ecology Progress Series 747:151-169. https://doi.org/10.3354/meps14699
Resource lineage
- Statement
- 𝟏. 𝐒𝐚𝐦𝐩𝐥𝐞 𝐜𝐨𝐥𝐥𝐞𝐜𝐭𝐢𝐨𝐧 Samples were collected from female AFSs breeding at 3 circumpolar sites in the Southern Ocean: (1) Marion Island (46° 52’ S, 37° 51’ E), in the Indian sector, (2) Bird Island (54° 00’ S, 38° 02’ W), off the northwest tip of South Georgia in the southwest Atlantic sector and (3) Cape Shirreff (62° 28’ S, 60° 48’ W), on the north coast of Livingston Island, in the South Shetland Islands, near the tip of the Antarctic Peninsula on the edge of the Pacific sector. Female AFS were captured between February and April each year (2008 to 2018) before beginning their winter non-breeding migration. Animals were captured and physically restrained using a hoop net and instrumented with a geolocator logger (GLS; MK19, British Antarctic Survey, Cambridge) to estimate at sea locations and duration of the winter migration. Geolocator loggers were attached to a metal tag placed between two plastic flipper tags that were inserted into the trailing edge of the fore flipper. Seals were recaptured and instruments recovered when pregnant females returned to the colony to pup the following breeding season, so the tracking data and samples reflect only the under-studied winter migration. Whole blood samples (1–5 ml) were collected from a hind flipper interdigital vein from adult female AFSs. Blood was sampled as soon as possible after females arrived at the breeding colony and when possible again at the end of the breeding season. Whole blood provides an indication of the consumer trophic ecology over the past 2–3 months. Samples collected at the start of the breeding season thus represent the last few months of the inter-breeding period, while samples collected at the end of the breeding season reflect foraging during the summer breeding period. One of the longest vibrissae, typically most distal to the nose, was cut as close to the face as possible, and the regrowth was cut again when females returned the following summer. 𝟐. 𝐋𝐚𝐛𝐨𝐫𝐚𝐭𝐨𝐫𝐲 𝐚𝐧𝐚𝐥𝐲𝐬𝐢𝐬 𝟐.𝟏. 𝐖𝐡𝐨𝐥𝐞 𝐛𝐥𝐨𝐨𝐝 𝐛𝐮𝐥𝐤 𝐚𝐧𝐝 𝐂𝐒𝐈𝐀-𝐀𝐀 Samples were stored at –20°C until isotopic analysis. Blood samples were dried at 60°C for at least 24 h prior to bulk and compound-specific stable isotope analyses (Walters et al. 2020 Friscourt et al. 2024). Dried blood samples were analysed for bulk δ13C and δ15N values (δ13Cbulk and δ15Nbulk) by combusting them in a Carlo-Erba EA1100 and passing the separated gases produced to an Isoprime continuous-flow isotope ratio mass spectrometer (IRMS). Replicate measurements of internal laboratory standards for δ15N (glycine, cysteine) and δ13C (glycine, cane sugar and beet sugar) indicated internal precisions better than 0.15‰, for both. Internal standards were previously calibrated against interlaboratory comparison standards distributed by the International Atomic Energy Agency (IAEA) and the USGS (L-glutamic acid, USGS 40 and USGS 41), except for ANU cane sugar, which was also the source of IAEA CH-6. Stable isotope ratios were reported using standard δ notation in parts per thousand (‰) deviation from the international standards Vienna PeeDee belemnite for δ13C and atmospheric nitrogen for δ15N as follows: δX = [(Rsample/Rstandard) – 1] × 1000 (1) where X is 13C or 15N, and R is the corresponding ratio of 13C/12C or 15N/14N. Dried blood samples were analysed for individual amino acid δ15N values (δ15NAA) (see supplementary material of Friscourt et al. 2024 for more information). The modification was the temperature and duration of the initial hydrolysis; we used 20 h at 110°C. The δ15N compositions of the individual amino acids were measured with a Trace GC Ultra gas chromatograph coupled to a Delta V Plus IRMS through a GC-C combustion furnace (980°C), reduction furnace (650°C) and liquid N2 cold trap. Each sample was analysed at least in duplicate. To normalize the δ15N values, a set of amino acid standards with known δ15N values was used to bracket the 2 distinct IRMS analyses. The slope and intercept of known vs. measured values were then used to correct the measured values for the sample set. The reproducibility of the isotopic analysis of individual amino acids calculated from the bracketing standards was ±0.48‰ (1 SD) and ranged from ±0.10 to ±0.71‰. 𝟐.𝟐 𝐖𝐡𝐢𝐬𝐤𝐞𝐫𝐬 𝐛𝐮𝐥𝐤 Whiskers were cleaned with 3 successive rinses in a 2:1 chloroform:methanol solution, and then oven-dried at 60°C for 72 h. Whiskers were measured, weighed and sectioned into approximately 3 mm sections (0.5-1.5 mg weight) following Walters et al. (2020). Samples were analysed for stable carbon (δ13C) and nitrogen (δ15N) isotopes by combusting them in a Carlo-Erba EA1100 (CE Instruments, Milan, Italy) and passing the separated gases produced to an Isoprime (Elementar, Cheadle SK8 6PT England) continuous-flow isotope-ratio mass spectrometer. All samples were processed at the Farquhar Laboratory, Australian National University (ANU), Canberra. Isotope values were reported using standard δ notation in parts per thousand (‰) deviation from the international standards (Vienna PeeDee Belemnite for carbon, and atmospheric nitrogen for nitrogen) as follows: δX = [(Rsample/Rstandard) – 1] × 1000, where X is 13C or 15N, and R is the corresponding ratio of 13C/12C or 15N/14N. As a control for the quality of keratin, we measured the carbon-to-nitrogen ratios (C:N) of each sample. Most of C:N ratios values are indicating good data quality (Newsome et al. 2010). Samples with a C:N ratio > 3.5 need to be excluded from further analysis. 𝟑. 𝐍𝐨𝐭𝐞 𝐨𝐧 𝐭𝐡𝐞 𝐚𝐧𝐢𝐦𝐚𝐥 𝐢𝐝𝐞𝐧𝐭𝐢𝐟𝐢𝐜𝐚𝐭𝐢𝐨𝐧 Individual seals are identified using numbered flipper tags. Because seals may be captured and re-tagged multiple times throughout the study period, a single individual can be associated with more than one tag number over time. To account for this, the SIA file includes a seal_tag column indicating the tag number at the time of sample collection, and an other_tag column listing any alternative tag numbers used for the same individual in earlier or later years. 𝟒. 𝐓𝐫𝐚𝐜𝐤𝐢𝐧𝐠 𝐝𝐚𝐭𝐚 𝐚𝐧𝐚𝐥𝐲𝐬𝐢𝐬 At present, GLS tracking data are only available for individuals from Marion Island. Tracking data from Cape Shirreff and Bird Island will be uploaded in a future version of the dataset. Geolocator loggers measured ambient light every minute and recorded the maximum value for every 10 minutes (5 minutes for Mk19 units). The light loggers on each device were calibrated at Marion Island for approximately 7 days either immediately before or after deployment to obtain a solar elevation curve at a known locality, which was necessary for location estimation. Locations were estimated using a variant of the method of Bindoff et al. (2017) in which the track is approximated by a linear interpolation in longitude and latitude. We defined the animal's location at specific control times through corresponding longitudinal and latitudinal coordinates. The track between these times was interpolated linearly. The locations at these control times were estimated using a Markov Chain Monte Carlo approach (Gilks et al. 1995), leveraging a likelihood function similar to that described in Bindoff et al. (2017). This function integrates contributions from recorded light data and the distance travelled. Light data analysis involved standard astronomical algorithms (Meeus 1991) to match recorded light against expected light conditions, assuming sensor obscuration in cases of non-recording during daylight. The travelled distance component was based on great circle distances between points, with animal speed assumed to follow a Gamma distribution. Finally, a block update Metropolis algorithm (Gilks et al. 1995) based on a multivariate Normal proposal distribution was used to draw samples from the posterior distribution of the locations and hence derive estimates of the track, as described in Sumner et al. (2009). The accuracy of location estimates using this approach was 70 ± 35 km for an Antarctic fur seal (AFS) carrying GLS and Argos tags simultaneously. Absolute Dynamic Topography (ADT), is a measure of the height of the ocean surface and a strong proxy for the location of time-mean location of Southern Ocean fronts. The ADT data used in this study are derived from satellite altimetry: the SSALTO/Duacs multi-satellite product, distributed by Copernicus Marine Services (https://doi.org/10.48670/moi-00148). We used the “level 4”, delayed time product that is provided on a regular 0.25°x0.25° grid at daily output frequency. The ADT is then bilinearly interpolated onto each of the individual AFS trajectories, so that for each timestamp, the AFS tracking data includes a latitude, longitude and ADT value.
- Hierarchy level
- Dataset
- Hierarchy level
- Dataset
Metadata
- Metadata identifier
- urn:uuid/977fa8d5-da00-4240-8767-e05e532c6bd0
- Language
- English
- Character encoding
- UTF8
Type of resource
- Resource scope
- Dataset
- Name
- IMAS Dataset level record
- Metadata linkage
-
https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/977fa8d5-da00-4240-8767-e05e532c6bd0
Point of truth URL of this metadata record
- Date info (Creation)
- 2025-09-19T00:00:00
- Date info (Revision)
- 2026-05-12T10:47:13
Metadata standard
- Title
- ISO 19115-3:2018
Overviews
Spatial extent
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E
W
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Provided by
Associated resources
Not available