Functional ecology of fish: current approaches and future challenges

Villeger et al. (2017) Aquatic Sciences 79: 783-801

Fish communities face increasing anthropogenic pressures in freshwater and marine ecosystems that modify their biodiversity and threaten the services they supply to human populations. To address these issues, stud- ies have been increasingly focusing on functions of  sh that are linked to their main ecological roles in aquatic ecosystems. Fish are indeed known to control other organ- isms through predation, mediate nutrient fluxes, and can act as ecosystem engineers. Here for each of the key functions played by  sh, we present the functional traits that have already been used to assess them. We include traits measurable from observations on living individuals, morphological features measured on preserved organisms or traits categorized using information from the literature, and we discuss their respective advantages and limitations. We then list future research directions to foster a more complete functional approach for  sh ecology that needs to incorporate functional traits describing, food provisioning and cultural services while accounting more frequently for intraspeci c variability. Finally, we highlight ecological and evolutionary questions that could be addressed using meta-analyses of large trait databases, and how a trait-based framework could provide valuable insights on the mechanistic links between global changes, functional diversity of  sh assemblages, and ecosystem services.