Counting whales in a challenging, changing environment

• Published in: Scientific reports Vol. 4; no. 1; p. 4170
• Main Authors: Williams, R., Kelly, N., Boebel, O., Friedlaender, A. S., Herr, H., Kock, K.-H., Lehnert, L. S., Maksym, T., Roberts, J., Scheidat, M., Siebert, U., Brierley, A. S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13-03-2014; Nature Publishing Group
• Subjects: 631/158; 631/158/672; Abundance; Aerial surveys; Animals; Antarctic Regions; antarctic sea-ice; Aquatic mammals; Climate; Climate Change; Conservation of Natural Resources; Data Collection; Ecosystem; edge; Environmental changes; Environmental impact; extent; Helicopters; Humanities and Social Sciences; Ice Cover; krill; Marine ecosystems; Minke Whale; multidisciplinary; Navigation behavior; ocean; Oceans and Seas; Population Density; Population Dynamics; Science; Sea ice; shelf; Trends; Whales; Whales & whaling; Whaling; Antarctic Regions
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep04170

Estimating abundance of Antarctic minke whales is central to the International Whaling Commission's conservation and management work and understanding impacts of climate change on polar marine ecosystems. Detecting abundance trends is problematic, in part because minke whales are frequently sighted within Antarctic sea ice where navigational safety concerns prevent ships from surveying. Using icebreaker-supported helicopters, we conducted aerial surveys across a gradient of ice conditions to estimate minke whale density in the Weddell Sea. The surveys revealed substantial numbers of whales inside the sea ice. The Antarctic summer sea ice is undergoing rapid regional change in annual extent, distribution and length of ice-covered season. These trends, along with substantial interannual variability in ice conditions, affect the proportion of whales available to be counted by traditional shipboard surveys. The strong association between whales and the dynamic, changing sea ice requires reexamination of the power to detect trends in whale abundance or predict ecosystem responses to climate change.