Relative abundance of large whales around South Georgia (1979-1998)

To assess large-whale stocks following the cessation of land-based South Ge orgia whaling in 1965, we report three independent sighting: databases: a c ruise in 1997, observations from Bird Island (NW of South Georgia) between 1979 and 1998, and mariner sightings between 1992 and 1997. All species wer e rare, with sightings of southern right whales being the most common event . Two right whales photographed off South Georgia matched animals known fro m Peninsula Valdes, Argentina, a population known to be growing at 7% per a nnum. In contrast, blue and fin whales appeared to be less abundant. A sing le blue whale mot-her-calf pair was observed off the Shag Rocks in February 1997. Extirpation. of animals from this particular feeding ground is the m ost likely reason for ongoing law numbers of all species. Other factors may include competition for krill by traditional predators such as penguins an d seals and more recently by humans, an unusually high rate of natural mort ality, habitat change such as alteration in sea ice coverage, and/or the im pact of ongoing whaling. The history of this critical area of large-whale h abitat and this report demonstrate the need for improved, consistent longte rm monitoring of population trends for these depleted stocks.