TODGHAM, A.E.*; FANGUE, N.A.; SCHULTE, P.M.; IWAMA, G.K.; University of British Columbia, Vancouver: Stress tolerance and the Hsp response of tidepool sculpins, Oligocottus maculosus, acclimatized to laboratory or field conditions

In nature, a fish�s thermal history is important in structuring its cellular response to stress. The plastic nature of the Hsp response and its involvement in inducible stress tolerance raises some fundamental questions regarding the environmental regulation of these protective processes. The intertidal zone offers a particularly good environment to investigate the effects of short-term changes in environmental conditions on the cellular stress response and stress tolerance. This study was designed to investigate the differences in the stress tolerance and Hsp response of field-collected (tidepool and subtidal) and lab-acclimatized tidepool sculpins (Oligocottus maculosus) exposed to both thermal and osmotic challenges. Sculpins acclimatized to ambient ocean conditions for 2 weeks experienced 57% and 50% mortality when exposed to severe thermal or osmotic challenges respectively. Sculpins collected from both tidepools and the subtidal zone experienced no mortality when exposed to the same heat shock. Osmotic tolerance of sculpins collected from the subtidal was not significantly different from that of lab-acclimatized fish; whereas, tidepool-collected sculpins were more tolerant, experiencing only 28% mortality. By examining the Hsp response of these fish to these stressors it is evident that tidepool-collected fish are able to mount a larger cellular stress response when compared to both lab-acclimatized and subtidal-collected sculpins. This may be one mechanism that facilitates their survival in this variable and unpredictable environment.