Arctic | Mammals
Identity and sex of Alaskan polar bears determined using DNA extracted from their footprints in snow Presenter: Andrew Von Duyke , Andrew.VonDuyke@north-slope.org, North Slope Borough Department of Wildlife Management Jennifer Adams , adamsj@uidaho.edu, University of Idaho - Laboratory for Ecological, Evolutionary and Conservation Genetics Justin Crawford , justin.crawford@alaska.gov, Alaska Department of Fish and Game - Arctic Marine Mammal Program Lori Quakenbush , lori.quakenbush@alaska.gov, Alaska Department of Fish and Game - Arctic Marine Mammal Program Lisette Waits , lwaits@uidaho.edu, University of Idaho - Laboratory for Ecological, Evolutionary and Conservation Genetics Polar bears ( Ursus maritimus ) are an iconic Arctic species, an important subsistence resource, and are listed as “threatened” under the US Endangered Species Act. As such, there is a growing need for reliable population data to inform their management. Given their remote and extreme habitat, polar bear research can be difficult, costly, and dangerous. With Arctic warming, longer open-water periods, and declines in the amount and reliability of sea ice as a safe platform upon which to operate, researchers face growing challenges to monitor polar bear populations. Because more traditional but invasive research methods are becoming less efficient, and are also problematic for stakeholders with animal welfare concerns, developing effective new methods to monitor polar bears that are less invasive and costly is a high priority. The analysis of environmental DNA (e-DNA) has the potential to address these challenges. Earlier analyses typically focused on detecting species presence – but recent efforts to identify individuals and their sex based on DNA collected from footprints in snow suggest the potential value of this method for population biology. We analyzed snow from the footprints of 13 polar bears sampled near Utqiaġvik and Kaktovik, AK to assess whether their identity and sex could be determined using e-DNA. Multiple footprints from an individual were combined into its sample – with 11 bear samples containing 5 footprints, and 2 bear samples containing 10 footprints. Snow from each bear’s sample was thawed and filtered to collect skin cells. After extracting the DNA, genotypes based on 7 microsatellite loci and sex chromosomes were successfully determined for 8 of the 13 (61.5%) bears sampled. Two negative blind controls were also analyzed and contained no polar bear DNA. These results suggest that it is possible to collect DNA from footprints in the snow of sufficient quantities and quality for microsatellite genotyping and sex identification of polar bears. These methods are also amenable to local participation in the co-production of knowledge. And by scaling up efforts to annually sample DNA from polar bear footprints at several Alaskan locations, it should be possible to directly inform and/ or to augment genetic mark-recapture abundance estimates, as well as to monitor movements and survival.
Alaska Marine Science Symposium 2023 286
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