Heart rate (beats min-1)
100
fHmax
80
60
20
TA
THRmax
20
25
30
35
Temperature (oC)
Fig. S1. Heart rate response to an acute increase in ambient temperature for a fish acclimated 19°C. Heart rate increases linearly until
a certain temperature and then the rate plateaus without increasing further. This maximum rate reached is fHmax and the temperature
at which fHmax is reached is THRmax. The temperature at which irregularities in the ECG signal occurred is denoted as arrhythmia
temperature (TA).
Maximum heart rates and temperature at maximum heart rate
Table S1. Maximum heart rate (fHmax) and temperature at onset of maximum heart rate (THRmax) in fish acclimated to
9, 19 and 26oC fish for 7 (N=3), 14 (N=3), 21 (N=3) and 28 (N=5-6) days and the ambient temperature (13oC)
(N=6).
Acclimation time
(days)
0
fHmax (beats min-1)
THRmax (oC)
99 ± 2.5
26.4 ± 0.23
09oC
7
14
21
28
88 ± 1.7p
76 ± 2.4a,q
79 ± 0.6a,q
91 ± 1.7x,p
24 ± 0.61a,p
19.9 ± 0.71a,q
24.2 ± 0.47a,p
24.1 ± 0.01a,p
19oC
7
14
21
28
121 ± 1.3a
124 ± 0.6a
124 ± 0.6a
120 ± 0.5a
27.8 ± 0.92p
32.2 ± 0.47a,q
32.6 ± 0.7a,q
34.2 ± 0.06a,r
26oC
7
14
21
28
104 ± 1.2p
119 ± 0.6a,q
128 ± 0.1a,r
135 ± 0.6a,s
34.1 ± 0.87a,p
34.2 ± 0.06a,p
36.8 ± 0.03a,q
36.1 ± 0.30a,q
Acclimation temperature
Ambient
fHmax is the temperature induced maximum heart rate recorded during an acute exposure to a heat ramp. Superscript ‘a’ indicates
statistical significance compared with the ambient temperature group. Superscript Letters p,q,r, and s denote statistically
significant differences across different time points within an acclimation group (mixed model two-way ANOVA, P<0.05).