Fig. 1. Seasonal variation in the number of ß-adrenergic receptors (ß-ARs; grey bars) and daily ambient water temperature (black line) throughout the study. Values are means ± S.E.M. (N=8). The inset shows the linear regression curve for ß-AR number vs mean water temperature (P=0.002, f(x)=474.7+74.1x, r²=0.417). Water temperature in the inset was calculated from the temperatures measured over the full period since the previous sampling.