Behaviour of ringed seals tagged with satellite transmitters in the North Water polynya during fast-ice formation

Abstract

To gain insight into the use by ringed seals (Phoca hispida) of the North Water polynya (northern Baffin Bay), we monitored the movements and diving behaviour of eight ringed seals caught in the fjords of the Thule (Avernarsuaq) area in Northwest Greenland. The animals were caught in August-September 1996 and equipped with satellite transmitters. Contact with the seals was maintained for up to 146 days. Two of the seals left the study area soon after being equipped, one moved north to the Kane Basin and one moved to southeastern Baffin Island. The departure of the other six seals from the fjords was apparently related to the formation of landfast ice. After formation of the polynya, all positions were close to the edge of the fast ice in the Thule area. Of the six seals that stayed in the North Water, three females preferred areas with shallow water (<100 m), while three males with larger body mass remained mainly in areas with deeper waters (>100 m). The "shallow-water" seals dove significantly more frequently to depths of less than 50 m than the "deep-water" seals, whereas the deep-water seals made significantly more dives that were deeper than 50 m. However, all seals occasionally dove to depths of more than 250 m.