Figure 1.
Map of Svalbard, Norway, showing the location of Prins Karls Forland, the core area for the harbour seal population, and Forlandsøyane, the major capture area for the 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in 2009 and 2010. The red and black dots show the location of the tidal and weather stations, respectively, that were used in the analyses of haul-out behaviour.
Table 1.
Factor variables.
Table 2.
Continuous variables.
Figure 2.
Duration of data records (“tag life”) for 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in Svalbard, Norway in 2009 and 2010. The grey rectangle represents the time period covered by the polar night (sun beneath the horizon), the yellow rectangles represent time periods covered by midnight sun and the white rectangles are light transition periods that include both night and daylight.
Figure 3.
Number of hours spent hauled out each day.
Mean daily number of hours (±95% CI) 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in Svalbard, Norway in 2009 and 2010, spent hauled out by season (month) and age group (pups, immature and mature seals). The number at the top of the CI bar indicates the maximum amount of time (hrs) an individual seal spent hauled out in that month and the number at the bottom of the CI bar indicates the number of seals transmitting data in that month.
Figure 4.
Time since previous haul-out event.
Output from a GAMM model showing the mean number of days (±95% CI) since the previous haul-out period, plotted by month for the 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in Svalbard, Norway in 2009 and 2010. The number at the top of the CI bar indicates the maximum time between haul-out events (days) for an individual seal and the number at the bottom of the CI bar indicates the number of seals transmitting data in that month.
Figure 5.
Terrestrial haul-out site locations and the use of specific sites by individual harbour seals.
Maps showing the location of terrestrial haul-out events performed by 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) (top) and the number of individual harbour seals using specific terrestrial haul-out sites (bottom) (30 tagged each year) in 2009 and 2010 in Svalbard, Norway. The island in the inset map is Prins Karls Forland, the principle breeding site and core distribution area for harbour seals in Svalbard.
Figure 6.
Non-terrestrial haul-out sites.
Maps showing the location of non-terrestrial haul-out events performed by 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in 2009 and 2010 in Svalbard, Norway. The seals hauled out on either shore-fast ice, drifting pack-ice or on floating glacier ice pieces (yellow dots in inset maps) in fjords, when annually formed sea ice was not available.
Figure 7.
Proportion of haul-out events on off-shore ice.
Smooth curves from a GAMM model, showing the proportion of haul-out events (mean (solid lines) ±95% CI (dotted lines)) performed by 60 harbour seals, equipped with Satellite-Relay Data Loggers (SRDLs) in Svalbard, Norway, which took place on off-shore ice, by month during 2009 and 2010.
Figure 8.
Haul-out behaviour indices vs solar hour.
GAMM smooth curves (A, C, E - mean (solid lines) ±95% CI (dashed lines)) showing impacts of solar hour on haul-out probability and hazard ratios from Cox Proportional Hazard (CPH) models (B, D, F) for the months where there is a day and night cycle (A,B), for the months of polar night (C,D) and for the months of midnight sun (E,F) for 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in 2009 and 2010 in Svalbard, Norway. [Hazard ratios beneath one indicate a decreased risk of ending a haul-out event and hazard ratios above one indicate an increased risk of ending a haul-out event.]
Figure 9.
Haul-out behaviour indices vs tide.
GAMM smooth curve (A, C, - mean (solid lines) ±95% CI (dashed lines)) showing impacts of the time to low tide (hrs) on haul-out probability and hazard ratios from Cox Proportional Hazard (CPH) models (B,D) for the months where the primary haul-out substrate is land (A,B) and the months where the primary haul-out substrate is sea ice (C,D) for the 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in 2009 and 2010 in Svalbard, Norway. [Hazard ratios beneath one indicate a decreased risk of ending a haul-out event and hazard ratios above one indicate an increased risk of ending a haul-out event.]