It could not be determined conclusively whether the walruses actually hauled out
on shore at these sites, and the tracking results do not suggest that terrestrial haul-out sites in the western part of Devon Island are used for longer periods of time and by a major proportion of the walruses from Smith Sound.
Caption: Thousands of walruses hauled out
on Cape Serdtse-Kamen', Russia Courtesy of Anatoly Kochnev/Russian Academy of Sciences
The average number of Sea Otters hauled out in the study area during the same haul-out event was 22, and the maximum number was 93.
The proportion of the total Sea Otters present in the study area that was hauled out per 30-min interval ranged between 0% and 96% for day and night combined.
The majority (98%) of Sea Otters hauled out were inactive and resting.
In conclusion, both the Hierarchical Partitioning and the significance of the variables in the full-model suggested a significant effect of hourly and daily water temperatures, tide- height, and wind speed on the number of Sea Otters hauled out. However, only Hierarchical Partitioning could tease out the significant contribution of decreasing air temperature to the increasing number of Sea Otters hauled out.
With the recent additions of a saltwater switch and a pressure sensor to the tag, the ASC can now document where a particular walrus is, how much time it spends hauled out
on land or sea ice, and where and for how long it is foraging.
These electronic devices, about the size of a roll of pennies, transmit a signal for four hours a day during mid-day, when seals are most likely to be hauled out
and more easily located; they last about five years.
Andrews, Scotland, were used to collect data on the time walruses spent in the water versus the time they spent hauled out (Fig.
The SRDLs continually monitor the data their sensors are collecting (surface sensor, depth sensor, and time interactions) and group the animals' activities into three different states: diving, hauled out, and at surface.
For this study, only the contrast between "not hauled out" (i.e., diving or at surface) and "hauled out" was of interest.
Weather effects on the proportion of animals hauled out at a particular time were explored using logistic regression models.
Mean fidelity, defined as the chance that an animal will return to an area where it previously hauled out, was 0.56 (SE = 0.09).
Here, we define fidelity as the chance that an animal will return to an area where it previously hauled out. We estimated fidelity to a haul-out area rather than to a specific point, because even after we filtered large location errors from the data, some unknown amount of location error remained.
In our analysis of fidelity among haul-out areas and between periods, the experimental unit was the animal and the sampling unit was an indicator of fidelity (1 if the animal returned to the area where it had previously hauled out; 0 otherwise).