HAUL-OUT AND DIVING ACTIVITY OF MALE ATLANTIC WALRUSES (ODOBENUS-ROSMARUS ROSMARUS) IN NE GREENLAND

During August-September 1989 and 1990, movements, haul out and dive ac tivity of male Atlantic walruses (Odobenus rosmarus rosmarus L.) were studied at a terrestrial haul-out site situated in an inshore foraging area in NE Greenland at 76 degrees 30' N. Data were collected from di rect observations of a group of about 50 males during August, includin g walruses that could be individually identified from natural markings , and from tracking of 8 adults equipped with satellite-linked radio t ransmitters during August-September. In both years, instrumented walru ses hauled out for a total of 29.3% of the sampling time. In 1989, whe n ice does were available for hauling out, the walruses spent 11% of t he time on ice, whereas in 1990, when ice was absent from the study ar ea, they only hauled out on land. Duration of haul-out periods, which did not differ between months or years, averaged 11 h (0.46 d) on ice (S.D. = 5.9, range: 1-29 h, n = 19 periods), and 38 h (1.6 d) on land (S.D. = 11.7, range: 13-64 h, n = 43). The walruses mainly hauled out during the afternoon and evening. Numbers hauling out on land during A ugust were negatively correlated with wind direction, precipitation (r ain) and wind-chill. In 1989, the duration of periods of absence from the terrestrial haul-out site (i.e. presumed foraging trips) averaged 206 h or 8.5 d (S.D. = 106.9, range: 48-412 h, n = 13), whereas, in 19 90, such trips averaged only 81 h or 3.4 d (S.D. = 37.9, range: 24-156 h, n = 24), reflecting that walruses used the haul-out, site more fre quently when ice was absent. Direct observations of foraging walruses showed that they were submerged about 81% of the time.