Recaptured ringed seals (Pusa hispida) in Greenland show diving patterns indicative of a behaviour related to daylight

This study describes the diving behaviour of three recaptured ringed seals ( Pusa hispida ) equipped with satellite relay data loggers (SRDL) in Greenland. Two of these ringed seals were tagged in Ilulissat Icefjord in West Greenland, one subadult male and one adult female, while an adult female was tagged in Sermilik in Southeast Greenland. The retrieved tags had stored all depth recordings (measurements every four seconds) and can, therefore, describe dives in more details than the compressed data relayed by satellites. The two adult females showed a diurnal difference in the diving behaviour, while the subadult male tagged in Ilulissat Icefjord showed a less obvious diurnal diving pattern. The high-resolution data suggest that the seal from Southeast Greenland had a diurnal dive pattern very similar to that of a common fish prey species (capelin, Mallotus villosus ) in Southeast Greenland according to acoustic surveys from the area. This paper show that some dive patterns that are obvious with high-resolution (4 s interval) are missed by the limitations of the SRDL transmission through satellites.