Figure 1.

The effect of increasing temperature on heart rate (f_H) of longfin smelt larvae. Representative plot of heart rate with temperature (A) and Arrhenius plot of f_H with increasing temperatures (B) for an individual larva. Average heart rate with temperature for all individuals (C) and Arrhenius plots of f_H with increasing temperatures (D) for different incubation temperature groups. Regression lines for representative Arrhenius plots are divided into two segments, representing the method by which Arrhenius breakpoint temperatures (T_AB) were determined for each individual. Unlike individual Arrhenius plots, grouped Arrhenius plots were best fit as 3 segments due to variation in post-T_AB changes in f_H across individuals. Dotted line indicates temperature where heart rate peaks (T_peak), dash-dotted line indicates temperature where cardiac arrhythmia was first observed (T_Arr), and dashed line indicates the T_AB. Data presented as mean ± SEM.