AQUATIC MATING STRATEGIES OF MALE BEARDED SEALS.i

Little work has previously been carried out on aquatic mating seals, as the logistic difficulty of studying these species hampered research. Recent developments in acoustic techniques have made the study of these species more feasible. The bearded seal, Erignathus barbatus, is a high Arctic ice breeding phocid which mates in the water. Female bearded seals give birth on ice floes or the edge of fast ice, a highly unstable substrate. In this study, patterns of male bearded seal vocalisations were studied in Kongsfjorden, Svalbard from April 1999 to June 2000. Males vocalised during a discrete 90-day period from early April to mid July, with a peak in late May. The frequency of vocalisations varied significantly with the diel cycle (increasing in number from 16:00 hrs onward and peaking around 04:00 hrs). This peak coincides with the period when most females are in the water. Female bearded seals were found throughout Kongsfjorden. Their distribution depends on the availability of suitable haul-our sites (ice floes or the ice edge). Males vocalised throughout the study site, however they vocalised in higher densities around the fjord entrances. They may use these ‘geographical bottlenecks ’ to maximise their chances at intercepting passing females. Male distribution appears to reflect the unpredictable nature of female haul-out distribution. 1