Arctic | Mammals
Ringed seal behavior and winter density in Prudhoe Bay, Alaska, determined by wildlife- detection dogs and instrumentation of subnivean lairs Presenter: Lori Quakenbush , lori.quakenbush@alaska.gov, Alaska Department of Fish and Game - Arctic Marine Mammal Program Anna Bryan , anna.bryan@alaska.gov, Alaska Department of Fish and Game Justin Crawford , justin.crawford@alaska.gov, Alaska Department of Fish and Game - Arctic Marine Mammal Program In Alaska, ringed seals ( Pusa hispida ) are an important subsistence resource to coastal Alaska Natives, and important prey for polar bears ( Ursus maritimus ). Ringed seals create and maintain breathing holes through solid landfast sea ice up to 2 m thick allowing them to use habitat both on (hauling out for resting, basking, and molting) and under (access to fish and invertebrate prey) sea ice during the winter. Ringed seals also use subnivean lairs built in snow drifts on top of sea ice and within pressure ridges for resting and pupping. Ringed seals were listed as threatened under the U.S. Endangered Species Act in 2012 because predicted declines in sea ice and snow accumulation over the next century were expected to greatly reduce their numbers. In the Beaufort Sea, ringed seal use of landfast ice in winter and early spring overlaps with oil and gas activities (e.g., ice road and gravel island construction, and seismic and drilling operations). Ringed seals spend most of their time underwater and in lairs and are generally not visible from the ice surface, thus determining how many seals may be affected by oil and gas activities is difficult, but necessary, for attaining permits to conduct these activities. In May 2022, we used two trained wildlife-detection dogs to survey an area in Prudhoe Bay, near Northstar Island, that was previously studied in 1983. During this survey we found 61 ringed seal structures (47 breathing holes and 14 lairs) in an 88.2 km2 area; a density of 0.68 structures/km2. Fewer structures were identified in 1983 (43; 16 breathing holes and 27 lairs) in a 96.8 km2 area; a density of 0.44 structures/km2. Snow depths at lairs were similar between studies and averaged 76.9 cm (range 45–120 cm) in 2022 compared to 78.7 cm (range 45–130 cm) in 1983. Lairs (12 of 14) were instrumented with temperature sensors, light sensors, and cameras to record lair use. Temperature sensors detected 10 haul-out bouts in three lairs, however photographs revealed extensive use of access holes for resting without hauling out and with minimal and brief increases in lair temperature. Breathing holes were found in water as shallow as 2 m and active structures were found within 19.5 m of facilities and within an active ice road. Two different basking seals were observed to stay on the ice during the close passage of a hovercraft. This area will be surveyed again in 2023 for further comparison.
Alaska Marine Science Symposium 2023 79
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