Temperature and the Vertical Distribution of Two Tidepool Fishes (Oligocottus maculosus, O. snyderi)

Abstract

The relationship between the tide cycle, microhabitat, temperatures, microdistribution patterns and thermal physiology of Oligocottus maculosus, and 0. snyderi, two tidepool cottids, was determined. Upper level tidepools generally are characterized by greater temperature extremes and sudden temperature shifts which are directly related to the periods of emergence and submergence. Lower tidepools tend to be more stable with a lesser extent of temperature extremes. Oligocottus snyderi, which is restricted to middle and lower tidepools, is less tolerant of wide temperature extremes. Its upper distributional boundaries appear to be governed by tidepool temperature extremes. Oligocottus maculosus, which is widely distributed but concentrated in upper level tidepools, is able to tolerate temperatures greater than those occurring in upper pools. Both species do not appear to be adversely affected by sudden temperature shifts.