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The Onset Temperature of the Heat-Shock Response and Whole-Organism Thermal Tolerance Are Tightly Correlated in both Laboratory-Acclimated and Field-Acclimatized Tidepool Sculpins ( Oligocottus maculosus )

2011; University of Chicago Press; Volume: 84; Issue: 4 Linguagem: Inglês

10.1086/660113

1537-5293

Nann A. Fangue, Edward J. Osborne, Anne E. Todgham, Patricia M. Schulte,

thermodynamics and calorimetric analyses

We examined the relationship between thermal tolerance, measured as critical thermal maximum (CTmax), and aspects of the heat-shock response in tidepool sculpins (Oligocottus maculosus) acclimated to constant laboratory temperatures or acclimatized to field conditions. The CTmax of fish laboratory acclimated to 6°, 13°, and 20°C were , , and , respectively, increasing linearly by 0.2°C for each 1°C increase in acclimation temperature. The CTmax of field-acclimatized fish from the low intertidal () was significantly lower than that of fish from the mid- () and high () intertidal. CTmax and the onset temperature of hsp70 induction in gill (Ton) were highly correlated in both laboratory-acclimated and field-acclimatized sculpins, with Ton occurring at 2°C below CTmax in all cases. However, there was no consistent relationship between CTmax and the maximum levels of gill hsp70 mRNA. Predicted "acclimation" temperature () and mean habitat temperature () were similar for sculpins from low intertidal pools, but this relationship was not apparent in mid- and high intertidal fish. Mark-recapture experiments indicated that approximately 80% of fish from low intertidal pools were residents of that pool, but residency rates were less than 50% in mid- and high intertidal pools, which may explain the lack of correlation between CTmax and habitat variables in these groups. These data indicate that gill hsp70 Ton and CTmax are highly correlated indicators of the thermal performance of tidepool sculpins in both laboratory and field settings.