The island of South Georgia is located at the southern extreme of the South Atlantic Ocean, on the edge of the Southern Ocean that surrounds Antarctica. Intensive commercial whaling at South Georgia began in 1904, when the first land-based whaling station was built in Grytviken (54°17'S, 36°30'W). Five other shore stations were eventually built: Ocean Harbour (54°20'S, 36°16'W), Leith Harbour (54°08'S, 36°41'W), Husvik Harbour (54°18'S, 36°71'W), Stromness Harbour (54°90'S, 36°41'W), and Prince Olav Harbour (54°40'S, 36°90'W). Another site, Godthul (54°17'S, 36°17'W), was used as a protected anchorage for floating factories. By 1965, when shore-based whaling activity ceased, over 175,000 whales had been processed on the island (Moore et al. 1999). The once abundant stocks of baleen whales in the Antarctic had at that time been reduced to about a third of their former sizes (Laws 1977). When considering blue (Balaenoptera musculus), fin (B. physalus), sei (B. borealis), and humpback (Megaptera novaeangliae) whales together, the average population size was reduced to ca. 18% (Laws 1977). Humpback and blue whales experienced the most severe bottlenecks, having been reduced to about 3% and 5% of the estimated initial populations, respectively. According to more recent estimates, even 80%–95% of the pristine populations of humpback, blue, and fin whales have been killed (Baker and Clapham 2002). For the blue whales depletion to even less than 1% of the pre-exploitation population size has been reported (Branch et al. 2004, 2007). Currently, knowledge about the recovery from the bottlenecks and current population sizes, structures, and migration patterns are important issues in the conservation of Southern Hemisphere baleen whales. In this context, insight into historical population structures would be of great value.
- Marine Sciences
- Ecology and Environment