Is there a trade-off between peak performance and performance breadth across temperatures for aerobic scope in teleost fishes?

The physiology and behaviour of ectotherms are strongly influenced by environmental temperature. A general hypothesis is that for performance traits, such as those related to growth, metabolism or locomotion, species face a trade-off between being a thermal specialist or a thermal generalist, implying a negative correlation between peak performance and performance breadth across a range of temperatures. Focusing on teleost fishes, we performed a phylogenetically informed comparative analysis of the relationship between performance peak and breadth for aerobic scope (AS), which represents whole-animal capacity available to carry out simultaneous oxygen-demanding processes (e.g. growth, locomotion, reproduction) above maintenance. Literature data for 28 species indicate that peak aerobic capacity is not linked to thermal performance breadth and that other physiological factors affecting thermal tolerance may prevent such a trade-off from emerging. The results therefore suggest that functional links between peak and thermal breadth for AS may not constrain evolutionary responses to environmental changes such as climate warming.