Using vocalizations of Antarctic seals to determine pupping habitats

Abstract

The Ross and Leopard seal use the floes of the Antarctic pack ice to whelp and raise their pups, But both species are rarely seen in summer throughout the pack ice. We now realize that this is because they are under the water ‘‘calling’’ during the austral summer as part of their breeding display, and so their presence is underestimated in traditional visual surveys. The period of ‘‘calling’’ overlaps with the time that females give birth, so their vocalizations can be used to determine seal distributions during this time. Acoustic recordings were made using sonobuoys deployed during ship based surveys in the pack ice and analyzed to determine the seal distributions. This was used to predict habitat preference of seals by relating their distributions to remotely sensed indices: ice cover, ice floe type, ice thickness, distance to ice edge, distance to shelf break, distance to land, sea surface temperature, and chlorophyll a.