Seasonal and diel cycles of fin whale acoustic occurence near Elephant Island, Antarctica

This study investigates the relevance of the Elephant Island region for Southern Hemisphere fin whales (Balaenoptera physalus) in their annual life cycle. We collected three years of passive acoustic recordings (Jan 2013 to Feb 2016) northwest of EI to calculate time series of fin whale acoustic indices, daily acoustic occurrence, spectrograms, as well as abundance of their 20-Hz pulses. Acoustic backscatter strength, sea ice concentration and chlorophyll a composites provided concurrent environmental information for graphic comparisons. Acoustic interannual, seasonal and diel patterns together with visual information and literature resources were used to define the period of occupancy and to infer potential drivers for their behaviour. Spectral results suggest that these fin whales migrate annually to and from offshore central Chile. Acoustic data and visual information reveal their arrival at EI in December to feed without producing their typical 20-Hz pulse. For all three years, acou...