Blue whales in Corcovado Bay, Chile: vocalizations and effects of anthropogenic noise

Blue whales (Balaenoptera musculus spp.) were once abundant in the Southern Hemisphere, but commercial whaling hunted them to near extinction in the previous century. The species is currently listed as endangered on the IUCN Red List of Threatened Species. The Chiloé-Corcovado region in Chile is one of the most important areas in the Southern Hemisphere for blue whales since it functions as a feeding and nursing ground. In recent years, ship traffic has increased considerably in the area and noise pollution is a major concern. In order to examine potential effects of ship noise on blue whale calling behavior, six Marine Autonomous Recording Units (MARUs) were deployed at four different locations (Northwest Chiloé, Guafo North, Tic Toc Bay and Locos Islet) between January 2012 and April 2013. A custom Matlab script is being used to analyze the acoustic data. Blue whale calls are detected automatically using a signal to noise ratio threshold in a particular third octave band that was found to best represent the call energy. In order to classify the calls and avoid false detections, the script output is corrected manually by comparing it with the spectrograms. Presence of ship noise is also systematically noted. Characteristics of blue whale calls when ship noise is both present and absent are being compared in order to examine if their calling behavior is affected by anthropogenic noise.

Promotor(s) & Supervisor: Laela Sayigh

ISCED Categories

The highlighted icons, represent the fields of education (in compliance with ISCED Classification) engaged during this course/programme.

0511 - Biology", "0521 - Ecology