Influence of vessel noises on underwater vocal activity of harp seals

Abstract

Recordings of harp seal (Pagophilus groenlandicus) underwater vocalizations were obtained on whelping patches in the Gulf of St. Lawrence, Canada. The seals vocalized throughout the day and night. A marked decrease in seal vocalizations occurred following the arrival of a vessel. The relatively loud motor noises of the vessel completely masked the seal calls (within a 2-km or more radius) except during the night when the vessel's motors were shut down. The decreased seal vocalizations may reflect a change in the seal's behaviour and (or) movement of some seals away from the area of the vessel.