Plasticity and Evolution in Atlantic Cod Populations during Climate Change

Abstract

It is increasingly recognised that ecology and evolution may interact on contemporary time scales and result in ongoing eco-evolutionary dynamics at population- community- and ecosystem levels. Therefore, an eco-evolutionary perspective is needed to better understand how fish populations may respond to ongoing and future climate change. This chapter highlights research on the impact of climate warming on population dynamics, life history and behaviour of Atlantic cod (Gadus morhua), specifically making the case of integrating ecological and evolutionary perspectives for understanding local adaptations and broader responses to climate change. The chapter focuses particularly on the interactions between genotypes and the environment, a reflection of phenotypic plasticity that can be graphically described as a reaction norm. With some exceptions, fish tend to be highly plastic, meaning that the phenotype being expressed by an individual will depend on the environment that it experiences during its lifetime, and potentially that experienced by its parents. Understanding the mechanisms and constraints related to such plasticity is therefore relevant for studies on the effects of climate change.