Since 1989, all Australian research proposals involving study of vertebrate animals in the Antarctic and sub-Antarctic have required the approval of the independent Antarctic Animal Ethics Committee (AAEC).
The AAEC has wide community representation. Its membership since its inception has included a representative of the Tasmanian Parks & Wildlife Service (now part of the Tasmanian Department of Primary Industries, Water and Environment, DPIWE) and the the animal welfare community.
The branding of young elephant seals began in 1993 following initial approval by the AAEC. This approval was renewed annually up to and including 1999. A major review of marking techniques undertaken by the AAEC in 1995 found that hot-iron branding was appropriate for this study.
The elephant seal program on Macquarie Island also requires the approval of the Tasmanian DPIWE. This approval has been given annually up to and including 1999.
The Australian Antarctic Division has notified the AAEC that the branding program would not continue. The last brandings occurred in late 1999. Plans for the continuation of this research do not include the use of hot-iron branding.
The southern elephant seal is a major top predator in the waters around Antarctica and as far north as Tasmania. Recognising its important role in the Southern Ocean ecosystems, Australian scientists have been studying the species since the 1940s, in particular its population fluctuations. Macquarie Island, an important breeding location, has always been a major focus of these studies.
The seal population dropped significantly in the middle 1960s and the current population is only about half what it was before 1965. It is still declining slowly but less slowly than on other sub-Antarctic islands. The conservation of this species is therefore an important issue.
A crucial part of this research is understanding the survival rate of elephant seals. Getting this information requires being able to keep track of seals over many years. The seals moult annually, which leaves branding or tagging as the best marking options. Tag loss becomes a significant problem after a number of years of life. Our research on freeze-branding (now used widely on livestock) shows that it does not work on this species.
Newer technologies such as implanted electronic tags have significant drawbacks because they require considerable daily disturbance to the seals in order to check seal identities. Brand marks can be read at a distance without disturbance to the animals.
The research program has enabled scientists to determine that:
- survival is usually good in the first year of life but sometimes drops catastrophically.
- the size of pups at weaning is a major determinant of survival in the first two years of life.
- survival in the animal's third year is surprisingly low.
Under the terms of AAEC approval, the branding process is carefully monitored and accurate records are kept of brand condition at the sighting of every animal. While infection occasionally occurs the brands have been found to heal well with 96 percent readability after one year. No death or significant injury is attributable to the branding.