Comment on ‘Measurement and relevance of maximum metabolic rate in fishes by Norin & Clark (2016)’

Reply to Zhang & Gilbert (2017): Comment on ‘Measurement and relevance of maximum metabolic rate in fishes by Norin & Clark (2016)’

“…In their case, however, the use of an unusually long exhaustion protocol (10 min chase, followed by 2 min of air exposure) means that may just as well have occurred during the 12 min chase and air‐exposure protocol rather than c . 5 to 12 min post‐exhaustion as implied (Figure in Zhang & Gilbert, ). That being said, we do appreciate their concern and show the data for all individual L. calcarifer in Fig.…”

“…In their Comment on our special‐issue article (Norin & Clark, ), Zhang & Gilbert () express how they had hoped for more precise definitions regarding the maximum aerobic metabolic rate (MMR) of fishes. Specifically, they worry that the terms ‘aerobic metabolic rate’ and ‘oxygen consumption rate’ are misleading, as the oxygen uptake rate from the environment is not necessarily the same as aerobic metabolic rate or oxygen consumption rate.…”

“…Finally, Zhang & Gilbert () argue that our adjustments of using specific Q 10 coefficients may have introduced uncertainty into the data used to rank species according to their ( cf . Table in Norin & Clark, ).…”

“…Table in Norin & Clark, ). They worry that this may be the case because , unlike minimum , purportedly reaches a plateau or declines at high temperatures in a wide range of fishes (Zhang & Gilbert, ). Zhang and Gilbert cite a few studies where this may be the case, but they fail to acknowledge recent literature, including an extensive meta‐analysis, which finds that in most fish species increases over most of the measured temperature range, showing no or only a minor decline as lethal temperatures are approached (Clark et al ., 2013 a , b ; Jutfelt et al ., ; Norin et al ., ; Lefevre, ).…”

“…acutely exposed fish and across methods (post‐chase or during exercise; Lefevre, ), although more work is required on these topics (Norin et al ., ; Killen et al ., ). Zhang & Gilbert () suggest that the Q 10 coefficient of 1·83 used to adjust some of our values is inappropriate as it describes interspecific relationships of fishes at rest, and they instead suggest that a Q 10 of 2·40 would have been more appropriate. This concern is understandable, but the fact that our adjusted values compare favourably to those of 121 fish species from a recent meta‐analysis which assumes no a priori temperature relationship (Killen et al ., ) suggests that our analytical approaches were reasonable.…”