Lethal Temperatures for Great Lakes Rainbow Trout

Abstract

Samples of progeny from wild rainbow trout (Salmo gairdneri) homing to four widely separated Great Lakes watersheds, when incubated and reared under similar conditions and acclimated to 15 C, did not differ in tolerance to upper lethal temperatures. The size of the individual fish under test did not affect the resistance time. The similar response of the four samples to upper lethal temperatures complements the conclusions previously reported from phenotypic observations of wild and cultured trout from the same four watersheds.

High thermal tolerance of a rainbow trout population near its southern range limit suggests local thermal adjustment

“…For example, thermal acclimation offsets the effect of acute warming on RMR in 5–7 g Mount Shasta and Eagle Lake O. mykiss (2.3–2.8 mg O 2 kg −0.95 min −1 at 14°C and 2.9–3.1 mg O 2 kg −0.95 min −1 at 25°C; Myrick and Cech, 2000), which would normally double RMR over this temperature range, as observed here. Warm acclimation can also increase upper thermal tolerance limits, as it did for four anadromous Great Lakes populations of juvenile O. mykiss (Bidgood and Berst, 1969). Given that our fish were captured at and, presumably, thermally acclimatized to between 14 and 17°C, it would be of interest to test wild fish with a warmer thermal acclimation history.…”

The Metabolic Costs and Physiological Consequences to Juvenile Rainbow Trout of a Simulated Winter Warming Scenario in the Presence or Absence of Sublethal Ammonia

“…By comparison, trout of equivalent age fed to satiation over summer (base thermal regime rising from 13°C to 21°C) grew at a rate of approximately 3.0%/d, as did the trout at +2°C in summer (Linton et al 1997). In this summer study, we concluded that the most significant effect of the +2°C warming scenario was the 30% reduction in food intake experienced by the warmed fish in the last 30 d, when water temperatures were approaching their upper lethal maximum (Bidgood and Berst 1969). A significant temperature‐dependent feeding effect was also experienced by the warmed fish of the present study; however, this time their food consumption increased by more than 30%.…”

A rainbow trout Oncorhynchus mykiss strain with higher aerobic scope in normoxia also has superior tolerance of hypoxia

“…The results of the present study clearly demonstrate intraspecific variation in O 2max , AAS, FAS, EPOC, O 2crit , ILOS and CT max among three strains of O. mykiss . In contrast, the majority of the previous studies that have independently examined variation in metabolic traits, hypoxia tolerance or upper thermal tolerance among strains of O. mykiss have found little evidence of intraspecific variation (Bidgood & Berst, ; Myrick & Cech, ; Rodnick et al., ; Scott et al., ). For instance, Scott et al .…”

“…Intraspecific differences in metabolic rate, aerobic scope, critical oxygen level, hypoxia tolerance and upper thermal tolerance are not novel observations in fish generally and several previous studies have assessed at least one of these traits in domestic or wild strains of O. mykiss from the U.S.A., Canada, Austria, Italy, Australia and Japan (Fry, ; Bidgood & Berst, ; Klar et al., ; Lee & Rinne, ; Wieser et al., ; Scarabello et al., ; Strange et al., ; Alsop & Wood, ; Currie et al., ; McGeer et al., ; Myrick & Cech, , ; Carline & Machung, ; Faust et al., ; Molony et al., ; Rodnick et al., ; Ineno et al., ; Galbreath et al., ; LeBlanc et al., ; Recsetar et al., ; Chen et al., ; Scott et al., ; Verhille et al., ). In particular, these studies have demonstrated substantial variation in upper thermal tolerance, hypoxia tolerance, routine O 2 and O 2max in O. mykiss , which could be indicative of a large amount of intraspecific variation in this species.…”