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)

• Published in: Physiological and biochemical zoology 2011-07, Vol.84 (4), p.341-352
• Main Authors: Fangue, Nann A., Osborne, Edward J., Todgham, Anne E., Schulte, Patricia M.
• Format: Article
• Language: English
• Subjects: Acclimatization; Animal Migration; Animals; British Columbia; Critical temperature; Environment; Female; Fish; Fishes - genetics; Fishes - physiology; Gene Expression Regulation; Heat tolerance; Heat-Shock Response; HSP70 Heat-Shock Proteins - genetics; HSP70 Heat-Shock Proteins - metabolism; Loggers; Male; Marine; Mark release recapture; Messenger RNA; Oligocottus maculosus; Polymerase Chain Reaction; RNA, Messenger - genetics; Sculpin; Shock heating; Temperature; Tidal Waves; Wildlife habitats
• ISSN: 1522-2152; 1537-5293
• DOI: 10.1086/660113

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 CTmaxof 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 CTmaxof field-acclimatized fish from the low intertidal ( ) was significantly lower than that of fish from the mid- ( ) and high ( ) intertidal. CTmaxand the onset temperature ofhsp70induction in gill (T on) were highly correlated in both laboratory-acclimated and field-acclimatized sculpins, withT onoccurring at 2°C below CTmaxin all cases. However, there was no consistent relationship between CTmaxand the maximum levels of gillhsp70mRNA. 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 CTmaxand habitat variables in these groups. These data indicate that gillhsp70 T onand CTmaxare highly correlated indicators of the thermal performance of tidepool sculpins in both laboratory and field settings.