Global Climate Change is rapidly altering the Arctic Ecosystem. In particular, the extent of sea ice cover has been decreasing (see sea ice map below). Many Arctic marine mammals rely on sea ice as a platform for important life history events. My research focused on the population ecology of sea-ice associated ringed seals. Ringed seals use sea ice as a platform for breeding, molting, and rearing pups. In order to evaluate whether rapid sea ice loss poses an extinction threat to ringed seals, in 2006, I began working on a project with Brendan P. Kelly and David Tallmon at the University of Alaska Southeast studying the circumpolar population-connectivity of ringed seals.
My work focused on estimating the level of gene flow among ringed seal subspecies in the Arctic Ocean, Baltic Sea, and Lake Saimaa Finland; as well as gene flow among Arctic breeding populations. We used satellite telemetry and population genetics to measure the dispersal capabilities of ringed seals and estimate the level of genetic relatedness among populations/subspecies.
We found that ringed seals undergo seasonal migration during the summer months when sea ice is minimal in the Arctic and seals can travel freely. Our genetic analyses also indicate that there are high amounts of gene flow among populations within the Arctic subspecies, and, surprisingly, despite seemingly geographic isolation, there is gene flow between the Arctic subspecies and the Baltic subspecies.
This work has resulted in the following two publications:
Martinez-Bakker ME, Sell SK, Swanson BJ, Kelly BP, & D Tallmon (2013). Combined genetic and telemetry data reveal high rates of gene flow , migration, and long-distance dispersal potential in Arctic ringed seals (Pusa hispida). PLOS ONE, Oct. 2013 vol. 8 issue 10, e77125. DOI: 10.1371/journal.pone.0077125. PDF online access available here.
Kelly BP, Badajos OH, Kunnasranta M, Moran JR, Martinez-Bakker ME, Wartzok D, & P Boveng (2010). Seasonal home ranges and fidelity to breeding sites among ringed seals. Polar Biology, 33: 8, 1095-1109. PDF
If you want to see a ringed seal in action you can check out this video of us tagging a seal in Barrow Alaska in 2008.
Photo by Kevin Bakker, Schematic by John Megahan