Population genomics of anadromous Arctic char (Salvelinus alpinus) in Nunavik

The Arctic charr (Salvelinus alpinus) is a species of main importance in traditional subsistence fisheries by Inuit communities in Nunavik. With the settlement of these populations and their demographic growth, concerns about overexploitation of fish stocks near the villages have been raised. In this context, knowledge about the genetic structure of Arctic char could be useful in managing the resource in a durable way, by delimiting management units in coherence with the biology of the species.

Most population of Arctic char in Nunavik are anadromous, meaning they migrate from the rivers to the sea to feed during summer. Unlike other anadromous salmonids, like the Atlantic salmon, the Arctic charr migrates in fresh water every year because of extreme conditions of salinity and temperature in arctic oceans. Moreover, chars are prone to straying whereas other species tend to prefer a homing strategy. This propensity to explore rivers other than their birthplace may affect the processes of structuration and differentiation between populations of Arctic char along the coast. The main objective of the project is to characterize this genetic structure.

To achieve this goal, fin or flesh samples will be collected on chars from different rivers along the northern coast of Nunavik. This will be done during fieldwork or by collaboration with local fishermen. DNA from those samples will be treated following the RAPTURE protocol. This new method of genotyping by sequencing (GBS) aims to reduce the complexity of the analysed genome by targeting sequences of interest. These sequences are chosen for their inclusion of single nucleotide polymorphism (SNP) markers and molecular baits must be designed prior to the sequencing of the DNA samples. This method greatly reduces the genotyping cost per individual and allows for large numbers of samples to be treated at once.

A secondary objective of the project will be to investigate local adaptations in Nunavik Arcitc char, due to contrasting oceanographic features. These analyses will mostly rely on data collected during missions of the research vessel and icebreaker Amudsen and may reveal local adaptations to environmental conditions.