Sperm whales year-round near Svalbard: new acoustic evidence from an international study

Sperm whales are present in the waters around the Svalbard archipelago throughout the year, with differences linked to age and sex. This is the key finding of a new study published in The Journal of the Acoustical Society of America, which includes the contribution of Manuel Bensi, oceanographer at the National Institute of Oceanography and Applied Geophysics – OGS.

The research – carried out in collaboration between OGS, the NATO Centre for Maritime Research and Experimentation, and the Institute of Polar Sciences of the Italian National Research Council (CNR) – used underwater acoustics to monitor sperm whale presence over time and to reconstruct the composition of the populations visiting these areas.

Scientists analyzed the “clicks” produced by sperm whales while searching for prey, recorded by seabed acoustic sensors. These signals not only indicate the presence of the whales but also make it possible to distinguish between different age classes and estimate group composition.

The data showed that sperm whales never completely leave the region: acoustic activity is higher in summer and autumn, when mixed groups of adults and juveniles are present, while in winter adult males prevail, providing evidence of sex-specific partial migration.

The study provides new insights into the ecology of sperm whales in a key area of the Arctic, which is currently affected by the phenomenon of Atlantification—that is, the growing influence of Atlantic waters in the Arctic Ocean contributing to sea ice loss and other impacts on the ecosystem, such as the arrival of Atlantic species in seas once covered by ice. Understanding how these large marine predators are distributed and how they move is crucial for assessing the impact of climate change on polar ecosystems.

Photo credits: Manuel Bensi