Measurements of aerobic and anaerobic locomotor cost of fish schools and solitary fish.
(A) Average traces of metabolic rate (MO2) of fish schools over a 40-hour experiment. Following the first 18-h quiescent state, a critical swimming speed (Ucrit) test quantifies the aerobic cost of active swimming. The ensuing 18-h measurement of excess post-exercise oxygen consumption (EPOC) quantifies the anaerobic cost. (B) Comparison of MO2 for conditions of aggregating behaviour, minimum demand speed, and resting condition with minimal flow (MO2aggregate, MO2min, MO2rest) (C) Comparisons of concave upward shaped MO2-speed curve over the entire range (0.3–8 body length s-1, BL s-1) and (D) the concave shaped MO2-speed curve at the lower speeds (0.3–3 BL s-1). (E, F) Percentage (%) aerobic scope used by fish schools and solitary fish during the Ucrit test. (G, H) Comparisons of EPOC and EPOC durations between fish schools and solitary fish. Statistical significance is denoted by asterisk(s). Green colour = school data (n=5 schools); blue colour = solitary fish data (n=5 individual fish); shading indicates the 95% confidence interval. Statistical details are available in the statistical analyses section.