A reconstruction of the demographic history of Canada's belugas

Background/Question/Methods

Canada's beluga populations are an essential part of the marine ecosystem. However, like many species over the last decades, these populations have been strongly impacted by human activities. Surveys suggest populations have declined in the recent past. Efforts have been made to protect these animals, however even under strict protective regulations some of these populations are not recovering as expected. To better facilitate the protection of animals in the future it will be vital to better understand the underlying genetic structure of these populations as well as understanding their current demography within the historic context. This study investigates beluga populations along the eastern coast of Canada. I use whole genomes of 81 individuals to do PCA and admixture analysis to find underlying genetic structure of these populations. The genetic groupings found then provides the basis for a reconstruction of the history of their effective population size throughout their past.

Results/Conclusions

I found three genetically distinctive groups. However, I also found outlier individuals which, while sampled from one group, clearly cluster with other populations. This indicates dispersal of some individuals between the populations over surprisingly long distances. There are clear demographic trends associated with the threat status of populations, with the overall effective population size of most beluga populations at the eastern Canadian shore being in decline.