Dr. Amanda Xuereb (Université Laval)
Dispersal, connectivity, and population genetic structure in the sea: insights from an exploited marine invertebrate and applications to spatial management
March 18th 12:30-1:30pm ET
Marine populations are typically characterized by weak genetic differentiation due to the potential for long-distance dispersal favouring high levels of gene flow. However, strong directional advection of water masses or retentive hydrodynamic forces can affect dispersal trajectories of marine organisms, thus influencing the degree of connectivity and genetic exchange among populations. We integrated genomic data derived from restriction site associated DNA sequencing (RAD-sequencing) with biophysical modelling of larval dispersal and use a spatial eigenfunction approach to infer the importance of ocean circulation as a driver of population genetic structure in a commercially harvested marine invertebrate in coastal British Columbia – the giant California sea cucumber (Parastichopus californicus). We demonstrated that ocean currents better predict patterns of genetic variation across space compared to geographic distance, and that directional processes play an important role in shaping spatial patterns of genetic structure, especially at relatively fine spatial scales. Our study emphasizes the importance of accounting for directional current flow in analyses of marine connectivity and contributes to the growing body of seascape genomics literature identifying significant population structure in marine systems despite the potential for widespread gene flow. Our findings have implications for designing reserve networks and for the spatial management of a commercially important species in the northeastern Pacific coastal region.