Macquarie Island southern elephant seal capture-mark-recapture data
Cite this dataset
Volzke, Sophia et al. (2023). Macquarie Island southern elephant seal capture-mark-recapture data [Dataset]. Dryad. https://doi.org/10.5061/dryad.zpc866t7f
Abstract
The Southern Ocean has been disproportionately affected by climate change and is therefore an ideal place to study the influence of changing environmental conditions on ecosystems. Changes in the demography of predator populations are indicators of broader shifts in food-web structure, but long-term data are required to study these effects. Southern elephant seals (Mirounga leonina) from Macquarie Island have consistently decreased in population size while all other major populations across the Southern Ocean have recently stabilised or are increasing. Two long-term mark-recapture studies (1956-1967 and 1993-2009) have monitored this population, which provides an opportunity to investigate demographic performance over a range of climatic conditions. This provides insights on individual vital rates of known-age seals from Macquarie Island over extensively long timeseries.
README: README
Macquarie Island southern elephant seal capture-mark-recapture history
Author: Sophia Volzke, University of Tasmania
Two long-term mark-recapture studies (1956-1967 and 1993-2009) have monitored the Macquarie Island breeding population of southern elephant seals (Mirounga leonina). These records provide an opportunity to investigate individual vital rates of known-age seals over extensively long timeseries.
Description of the data and file structure
Between 1951-1965 and 1993-1999 weaned Southern Elephant Seals were captured and marked permanently by hot iron branding. Seals were recorded in regular re-sights varying from daily isthmus searches during the breeding season to ad-hoc sightings outside of active monitoring. Biological data from individual short-term scientific projects includes information on physical condition for a sub-set of pups and adult seals.
Data includes a header row with descriptions for columns:
- SIGHTING_ID: Uniquely assigned number of each sighting (numeric)
- WEIGHT: Weight of the individual (in kg)
- SEX_ON_SIGHTING: Sex assigned during re-sighting (M Male or F Female)
- SEAL_TAGS_ON_ANIMAL: Number of flipper tags on animal (0, 1, 2 or U - unknown)
- MASTER_SEX_CHECKED: Sex of animal as assigned upon tagging and checked across adult sighting records (M Male; F Female; U Unknown)
- SEAL_ID: Unique identifier of animal, as assigned by brand and/or tag ID code (numeric)
- MASTER_TAG_TYPE: Roto Flipper Tags or Branding method used for tagging (T Tags; B Branding; BT both tags and brands)
- MOULT_ID: State of moult in thirds (1/3 < one third moulted, 2/3 < two thirds moulted, 3/3 = between 2/3 and 3/3, and 5/3 for complete moult. 99 if not moulting)
- MODIFIED_BY: Name of researcher
- ENTERED_BY: Name of researcher
- DATE_OBSERVED: Observation date format DD/MM/YYYY
- DATE_MODIFIED: Record modified date format DD/MM/YYYY
- DATE_ENTERED: Entered date format DD/MM/YYYY
- COMMENTS: Text
- SEAL_STATUS_ID: Number indicating breeding status upon sighting (01 McPherson; 02 Harem Cow with Pup; 03 Dominant Bull; 04 Assistant Beachmaster; 05 Challenger; 06 Bachelor Gay; 07 Pregnant Cow; 08 Moulting; 09 Midyear haul-out; 10 Post-partum Cow; 11 End-lactation Cow; 12 Cow with dead pup; 13 Cow who has abandoned pup; 14 Cow with adopted pup; 15 Cow who has aborted pup; 16 Copulating Cow; 99 Unknown)
- AGE_CLASS_ID: Number indicating age class upon sighting (01 Black Pup; 02 Weaned Pup; 03 Suckling Pup; 04 Post-wean Pup; 05 Abandoned pup; 10 Underyearling; 20 Yearling; 30 Subadult; 40 Adult; 50 Dead; 99 Unknown)
Sharing/Access information
This dataset is publicly available and has been kept updated as seals are sighted and this population continues to be monitored annually.
Links to other publicly accessible locations of the data:
- Australian Antarctic Data centre: (1950 to 1965) https://data.aad.gov.au/metadata/records/AADC-00101 (1985 Onwards) https://data.aad.gov.au/metadata/records/AADC-00102
Code/Software
Comma separated value (CSV) file able to be accessed through Microsoft Excel, R Studio or other analytical software.
Methods
Between 1951–1965 and 1993–1999 weaned Southern Elephant Seals were captured and marked permanently by hot iron branding. Seals were recorded in regular re-sights varying from daily isthmus searches during the breeding season to ad-hoc sightings outside of active monitoring. Biological data from individual short-term scientific projects include information on the physical condition for a sub-set of pups and adult seals.
Usage notes
Comma separated value (CSV) file able to be accessed through Microsoft Excel, R Studio or other analytical software
Funding
University of Tasmania