About Migration:

Migration involves the movement from one area to another, and back again. This movement is usually related to food availability or reproduction.

Basking Shark Migration:

Shark scientists have questioned basking shark migration for decades. An an article in 1954 proposed that basking sharks hibernated on the ocean bottom during the winter, as shark sightings were scarce once cold weather hit.

Tagging studies on sharks have revealed new information on at least one population of basking sharks.

Western North Atlantic Basking Sharks:

Basking sharks that spend their summers in the western North Atlantic Ocean are not seen in that area once the weather cools. It was once thought that these sharks might spend their winters hibernating on the ocean bottom.

In a 2009 study, scientists reported in Current Biology that Western North Atlantic basking sharks likely go south for the winter. Researchers from the Massachusetts Division of Marine Fisheries and their colleagues fitted 25 sharks off of Cape Cod with tags that recorded depth, temperature and light levels. The sharks swam off, and by wintertime, they had crossed the equator - some even went all the way to Brazil.

While in these southern latitudes, the sharks spent their time in deep water, ranging from about 650 to 3200 feet deep. Once there, the sharks remained for weeks to months at a time.

Eastern North Atlantic Basking Sharks:

Studies on basking sharks in the UK have been less conclusive, but the Shark Trust reports that the sharks are active all year. During the winter, these basking sharks also migrate to deeper waters, and shed and re-grow their gill rakers.

Sharks may also migrate across the Atlantic. In a study published in 2008, a female shark was tagged for 88 days (July-September 2007) and swam from the UK to Newfoundland, Canada.