Applied fish bioenergetics

Energy is a fundamental currency of life that can be quantified in organisms to understand how environmental conditions and anthropogenic stressors affect individuals, scaling up to populations and entire ecosystems. Bioenergetics studies have been conducted extensively on fishes, with an historical focus on lab-based experiments relevant to fisheries and aquaculture; however, recent methodological and technological advances are enabling more widespread applications in ecology and conservation including in situ measurement of various aspects of fish bioenergetics in aquatic ecosystems. Much of the utility of bioenergetics is based on a generalized mass-balance equation that describes energy allocation, and there are numerous advanced modeling techniques available to quantify how various environmental and intrinsic biological factors influence fish energetics, as well as relevant endpoints such as growth and reproduction. In this chapter, we discuss (1) key components of fish bioenergetics, (2) available measurement techniques, (3) common modeling techniques, and (4) case studies that highlight some key applications to date. We conclude by discussing current limitations and future research directions in this field. Bioenergetics is an increasingly powerful approach to build mechanistic connections between environmental conditions, stressors, and fish populations that is especially valuable for predicting the responses of fishes to rapidly changing conditions in the Anthropocene.