Combining stereo‐video monitoring and physiological trials to estimate reef fish metabolic demands in the wild

• Published in: Ecology and evolution Vol. 12; no. 7; pp. e9084 - n/a
• Main Authors: Schiettekatte, Nina M. D., Conte, Francesca, French, Beverly, Brandl, Simon J., Fulton, Christopher J., Mercière, Alexandre, Norin, Tommy, Villéger, Sébastien, Parravicini, Valeriano
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.07.2022; Wiley Open Access; John Wiley and Sons Inc; Wiley
• Subjects: activity; activity scope; Aquatic animals; Biodiversity and Ecology; Biotelemetry; Body size; Climate change; Community Ecology; Coral reefs; Ecosystem Ecology; Ecosystems; Environmental Sciences; field metabolic rate; Fish; Fishing; Fluxes; Functional Ecology; Growth models; Laboratories; Marine ecosystems; Marine fish; Metabolic rate; metabolic scaling; Metabolism; Movement Ecology; Physical fitness; Physiology; Reef fish; Respirometry; Species; Swimming; swimming speed; swimming speed; field metabolic rate; activity; activity scope; fish; metabolic scaling; metabolism
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.9084

Organismal metabolic rates (MRs) are the basis of energy and nutrient fluxes through ecosystems. In the marine realm, fishes are some of the most prominent consumers. However, their metabolic demand in the wild (field MR [FMR]) is poorly documented, because it is challenging to measure directly. Here, we introduce a novel approach to estimating the component of FMR associated with voluntary activity (i.e., the field active MR [AMRfield]). Our approach combines laboratory‐based respirometry, swimming speeds, and field‐based stereo‐video systems to estimate the activity of individuals. We exemplify our approach by focusing on six coral reef fish species, for which we quantified standard MR and maximum MR (SMR and MMR, respectively) in the laboratory, and body sizes and swimming speeds in the field. Based on the relationships between MR, body size, and swimming speeds, we estimate that the activity scope (i.e., the ratio between AMRfield and SMR) varies from 1.2 to 3.2 across species and body sizes. Furthermore, we illustrate that the scaling exponent for AMRfield varies across species and can substantially exceed the widely assumed value of 0.75 for SMR. Finally, by scaling organismal AMRfield estimates to the assemblage level, we show the potential effect of this variability on community metabolic demand. Our approach may improve our ability to estimate elemental fluxes mediated by a critically important group of aquatic animals through a non‐destructive, widely applicable technique. We know little about the metabolic demand of fishes in the wild. We propose a new approach to estimate active field metabolic rates by combining laboratory‐based respirometry and field‐based stereo‐video systems.