Shoaling Reduces Metabolic Rate in a Gregarious Coral Reef Fish Species
Society for Experimental Biology Annual Conference / Brighton, United Kingdom
Many animals live in groups due to the benefits that sociability can confer. For instance, group-living can reduce the energetic requirements needed to fuel a variety of processes, such as flight in birds, swimming in fish, web-building in spiders and thermoregulation in mice. Theory also suggests that group living may induce a ‘calming effect’ through a variety of mechanisms, reducing the physiological stress experienced by group members and, potentially, reducing individuals’ total metabolic demand. However, this effect has proven difficult to quantify. In this study, we measured the impacts of shoaling on the metabolism and body condition of a gregarious coral reef fish species, the shoaling damselfish Chromis viridis. Using a novel respirometry methodology for a social species, we found that the presence of shoal-mate cues led to a significant reduction in the measured standard metabolic rate of individuals. Although all fish were fed a body-mass specific feeding regime, fish held in isolation exhibited a significant reduction in body condition following one week in treatment when compared to those held in shoals. Interestingly, individuals accustomed to the group holding treatment exhibited a stronger initial physiological reaction to stress than those acclimated to an isolated condition, potentially due to the stress of acute isolation and a lower threshold of threat at which they instigate a stress response. As environmental disturbances have the potential to induce social isolation, these results could have ecological consequences for gregarious species.
Nadler, Lauren E.; Killen, Shaun S.; McClure, Eva C.; Munday, Philip L.; and McCormick, Mark I., "Shoaling Reduces Metabolic Rate in a Gregarious Coral Reef Fish Species" (2016). Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures. 738.