Subset of data from the TAGS database of known age seals - Weddell Seals

Brief description

This database is a compendium of histories of known age seals (Weddell) from observations across the Southern Ocean but focussed on the Windmill Islands, Mawson and the Vestfold Hills. Although the following information pertains to Elephant Seals, it is assumed similar procedures were undertaken with the Weddell Seals between 1973 and 2006:

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.

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.

Lineage

Progress Code: completed

Statement: Observations are approximately 95% accurate. Errors in observation and entry possible where animals are misplaced.

It is strongly recommended that prospective users of these data contact the investigators before using these data.

Mark Hindell Mark.Hindell@utas.edu.au
Clive McMahon clive.mcmahon@utas.edu.au
John van den Hoff John.Vandenhoff@aad.gov.au