Historical population dynamics of ringed seals, <i>Pusa hispida</i>, of the Svalbard archipelago:Predicting the response to climate change

The ringed seal (Pusa hispida) is a pagophilic seal species with a life cycle closely associated with the sea ice and also the key prey species for the polar bear (Ursus maritimus). Global warming is rapidly diminishing the extent of summer sea ice in the Arctic, greatly reducing habitat availability for ringed seals and indirectly influencing the prey availability for polar bears. Predicting the effects of climate change on the abundance of ringed seals is essential for effective long-term management, but is challenging due to the complex relationship between climate change and ecological dynamics. Understanding how the historical population dynamics of ringed seals have responded to past climate may provide insights into the responses to current and future climate changes. In this study we have employed the Bayesian skyline plots, a coalescence-based method for inference of historical population dynamics, using mitochondrial DNA control region nucleotide sequences collected from ringed seals and polar bears at the Svalbard. Our analysis revealed a pattern of population expansion followed by contraction in ringed seals, suggesting a possible correlation with historical sea ice dynamics. Preliminary results from the polar bear suggest a correlation with ringed seal population dynamics. Additional on-going data analyses of a large number of high-resolution SNPs will add further rigor to our study. Our findings have implications for conservation of ringed seal and polar bear, in addition to providing insights into the evolutionary ecology of key polar marine mammals in the Arctic