Seasonal patterns in acoustic detections of marine mammals near Sachs Harbour, Northwest Territories

Abstract

The Arctic is changing rapidly, leading to changes in habitat availability and increased anthropogenic disturbance. Information on the distribution of animals is needed as these changes occur. We examine seasonal presence of marine mammals in the western Canadian Arctic near Sachs Harbour, Northwest Territories, using passive acoustic monitoring between 2015 and 2016. We also examined the influence of environmental variables (ice concentration and distance, wind speed) on the presence of these species. Both bowhead whales (Balaena mysticetus) and beluga whales (Delphinapterus leucas) arrived in late April, and belugas departed in mid-August, while bowheads departed in late October. Bearded seal (Erignathus barbatus) vocalizations began in October, peaked from April through June, and stopped in early July. Ringed seals (Pusa hispida) vocalized occasionally in all months, but were generally quiet. Whales migrated in as the ice broke up and migrated out before ice formed in the autumn. Bearded seals started vocalizing as ice formed and stopped once ice was almost gone. Given the importance of sea ice to the timing of migration of whales and vocalization by bearded seals, the trends that we present here may change in the future due to the increasing ice-free season caused by climate change. Our study therefore serves as a baseline with which to monitor future change.