The Interplay of Functional Traits and Genetic Diversity in Fish Population Resilience Under Climate Change

Populations’ persistence relies on their demography in the short-term and their adaptive capacity in the long-run. The former is known to depend on species’ functional traits whereas the latter is determined by species’ intraspecific genetic diversity (IGD). However, several empirical and theoretical studies have shown that species’ life-history traits and IGD are related thus linking species’ demography and evolution. Such link is critical to understand the eco-evolutionary response of species to short-term pressures, notably climate change. In marine fish, small-bodied short-lived pelagic species are for instance known to be more sensitive to climate whereas large-bodied long-lived demersal species are more vulnerable to fishing. The interplay between species’ IGD and functional traits will therefore determine the eco-evolutionary resilience of populations to natural and anthropogenic pressures.

Here, we model fish’ functional traits and genetic diversity with Ev-OSMOSE, a new individual-based eco-evolutionary ecosystem model representing fish communities. From these simulations we deduce how fish species’ IGD is affected by their functional traits. As the mechanisms linking functional traits and IGD might be affected by external pressures, we forecast fish community eco-evolutionary pathways and distribution shift under climate change and fishing.

Our results confirm that life-history traits affect genetic diversity and show how functional traits such as the trophic level or habitat influence fish IGD. This work provides insights for evolutionarily-enlightened fish stocks management under climate change.