Medium-term acoustic monitoring of small cetaceans in Patagonia, Chile.

Coastal dolphins and porpoises such as the Chilean dolphin (), the Peale's dolphin (), and the Burmeister's porpoise () inhabit the remote areas of Chilean Patagonia. Human development is growing fast in these parts and may constitute a serious threat to such poorly known species. It is thus urgent to develop new tools to try and study these cryptic species and find out more about their behavior, population levels, and habits.

Mathematical models of long term evolution of blue whale song types' frequencies.

The linear decrease in the frequency of blue whale songs around the world is, to date, an unexplained phenomenon. We show it can be reproduced by a mathematical model considering two antagonistic behavioral trends: first, a bias towards conformity in the song, and second, a tendency to try and sing lower than the other whales. We check the robustness of our model by considering some more complex premises.

Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types.

A decrease in the frequency of two southeast Pacific blue whale song types was examined over decades, using acoustic data from several different sources in the eastern Pacific Ocean ranging between the Equator and Chilean Patagonia. The pulse rate of the song units as well as their peak frequency were measured using two different methods (summed auto-correlation and Fourier transform). The sources of error associated with each measurement were assessed.

A standardized method of classifying pulsed sounds and its application to pulse rate measurement of blue whale southeast Pacific song units.

Pulsed sounds are an interesting example of complex biological sounds, frequent in cetaceans' vocalizations. A two-group classification of these sounds is proposed: tonal or non-tonal. Through two simple mathematical models, it is shown that this classification can lead to better techniques for measuring the pulse rate.