. (2003). The effect of temperature on swimming performance and oxygen consumption in adult sockeye (Oncorhynchus nerka) and coho (O. kisutch) salmon stocks. J. Exp. Biol. 206,[3239][3240][3241][3242][3243][3244][3245][3246][3247][3248][3249][3250][3251] In both the on-line and printed versions of this paper, some of the equations in the legends to Figs 2-4 were printed incorrectly.On page 3245, in the legend to Fig.·2, the two equations should read:M O 2 routine =2.12+0.09e 0.18t (ambient; broken line) and M O 2 routine =1.39+0.54e 0.08t (adjusted; solid line).On page 3246, in the legend to Fig.·3 The authors apologise for any inconvenience these errors may have caused.Temperature has been coined the 'ecological master factor' for fish (Brett, 1971), and important physiological functions such as growth, swimming performance and active metabolic rate can have species-specific temperature optima that are near a species-preferred or acclimated temperature (Fry, 1947;Brett, 1971;Dickson and Kramer, 1971;Beamish, 1978;Houston, 1982;Bernatchez and Dodson, 1985;Johnston and Temple, 2002). Thus, when fish are exposed to temperature changes, they can obtain optimal performance by altering either their behaviour (preference/avoidance) or their physiology (adaptation and acclimation), when the temperature change is sufficiently long. Certain short-term variations in temperature may be unavoidable, however, and this is particularly the case for adult migratory salmon that are returning to their natal streams to spawn. For example, water temperatures in one of the world's greatest salmon-bearing rivers, the Fraser River, BC, Canada, may vary annually on a given date by as much as 6°C. Furthermore, the river temperatures encountered by the Early Stuart stock of Fraser River sockeye salmon Oncorhynchus nerka during its 25-day migration can vary by as much as 10.5°C (Idler and Clemens, 1959) and reach up to 22°C .Given the adult salmon's short migration window and its exposure to a wide variation in temperature, it is possible that acclimation mechanisms that would normally compensate for temperature change may be incomplete. Conversely, Guderley and Blier (1988) suggest that swimming performance and most of its components demonstrate thermal compensation on an evolutionary time scale (i.e. adaptation) such that optimal performance and lowest thermal sensitivity are typically within the temperature range most frequently encountered by the organism. In the case of adult salmon stock, the prediction is that they would retain sufficient physiological flexibility to accommodate the range of temperatures most frequently Our knowledge of the swimming capabilities and metabolic rates of adult salmon, and particularly the influence of temperature on them, is extremely limited, and yet this information is critical to understanding the remarkable upstream migrations that these fish can make. To remedy this situation, we examined the effects of temperature on swimming performance and metabolic rates of 107 adult fish taken from three sto...

test temperature. The non-aerobic cost of swimming to Ucrit was estimated to add an additional 21.4-50.5% to the oxygen consumption measured at U crit. While these nonaerobic contributions to swimming did not affect the minimum cost of transport, they were up to three times higher than the value used previously for an energetic model of salmon migration in the Fraser River, BC, Canada. As such, the underestimate of non-aerobic swimming costs may require a reevaluation of the importance of how in-river barriers like rapids and bypass facilities at dams, and year-to-year changes in river flows and temperatures, affect energy use and hence migration success.

Novel field measurements of critical swimming speed (Ucrit) and oxygen uptake ( Mo2) in three species of adult Pacific salmon Oncorhynchus spp. up to 3·5 kg in body mass were made using two newly designed, mobile Brett‐type swim tunnel respirometers sited at a number of field locations in British Columbia, Canada. Measurements of Ucrit, which ranged from 1· 68 to 2·17 body lengths s−1, and maximum Mo2, which ranged from 8·74 to 12·63 mg O2 kg−1 min−1 depending on the species and field location, were judged to be of similar quality when compared with available data for laboratory‐based studies. Therefore high quality respirometry studies were possible in the field using adult wild swimming salmonids. In addition, the recovery of wild adult Pacific salmon from the exhaustive Ucrit swim test was sufficiently rapid that swimming performance could be repeated with <1 h of recovery time between the termination of the initial swim test and the start of the second test. Moreover, this repeat swimming performance was possible without routine Mo2 being reestablished. This result suggests that wild adult salmon are capable of carrying a moderate excess post‐exercise oxygen consumption without adversely affecting Ucrit, maximum Mo2 or swimming economy. Such capabilities may be extremely important for timely migratory passages when salmonids face repetitive hydraulic challenges on their upstream migration.