Foraging areas, migratory movements and winter destinations of blue whales from the western North Atlantic

Abstract

The blue whale Balaenopterus musculus is a wide-ranging cetacean that can be found in all oceans. In the North Atlantic, little is known about blue whale distribution and genetic structure, or about the interconnections between areas of aggregations in Icelandic waters, the Azores, Northwest Africa, and the Northwest Atlantic. Seasonal movements and habitat use of blue whales, including the location of breeding and wintering areas, are also poorly understood. We used satellite telemetry to track movements of 23 blue whales from eastern Canada, providing the first record of the migratory movements and winter destinations of western North Atlantic blue whales. Cabot Strait, the largest outlet connecting the Gulf of St. Lawrence to the Atlantic, was identified as the main corridor for movements in and out of this high-latitude feeding area. The Mid-Atlantic Bight, located off the southeastern USA, was identified as a wintering, and possibly breeding or calving, area. We confirmed the extended use of key summer feeding areas in the St. Lawrence Estuary and northwestern Gulf of St. Lawrence into the fall, and provided evidence for new feeding areas off southern Newfoundland and Nova Scotia. Our results indicate that there is likely a strong connectivity among blue whale areas of concentration at northern latitudes. They also suggest sporadic foraging outside the feeding season, and highlight seamounts and other deep ocean structures as potentially important blue whale habitats. Globally, our study emphasizes the large scale (i.e. many thousands of square kilometers) one needs to consider when addressing the conservation issues faced by blue whale populations.