
Fig. 8. Mean propulsive wavelength (
) versus fork length
(FL) for individual chub mackerel at 18 °C (open squares) and 24
°C (filled squares). Because there was no significant effect of speed on
, the mean of the propulsive wavelengths at all swimming speeds was
calculated for each individual. Error bars represent ±1 S.E.M. The
lines are the best-fitting linear regressions:
=1.11FL-1.32,
r2=0.89, N=9, P<0.001, at 18 °C
(dashed line);
=1.09FL+1.32, r2=0.83,
N=12, P<0.001, at 24 °C (solid line). Mean
increases with FL at the same rate at the two temperatures but, at a
given FL,
is significantly greater at 24 than at 18 °C
(ANCOVA, P=0.0024).