Aerobic swimming performance in fish: an analysis of current practices and proposal of a new alternative

Abstract

Protocols for measuring aerobic swimming performance vary greatly in the field of fish physiology. A large divide exists between studies that track oxygen consumption, and those that just report maximum swimming speeds. Among these studies, variables such as acclimation and fasting times, as well as the length of the trial and the speeds at which an individual swims, have a variety of acceptable protocols. The aim of this study was to compare oxygen consumption values obtained with traditional increasing interval tests (Ucrit) with a randomized and a truncated version, in order to determine if these varying protocols produce similar results. The minimum time needed to acclimate to reach routine metabolic rate (RMR) ranged from 10-12hrs depending on the species. Oxygen consumption (MO2) values were significantly higher in speeds up to 75% of maximum swimming speed when a randomized speed design was used. A truncated version of the increasing speed protocol that only used three speeds yielded MO2 values that were not significantly different than those obtained with the traditional method. These results suggest that traditional methods may underestimate aerobic scope, but randomizing speeds may overestimate MO2 at a given speed. Using a truncated method may also be useful for studies under a time constraint.