FIGURE 4 Between-year correlations of water temperature (a) and water
level (b). Time windows are relative to the arrival timings of the same
Sakhalin taimen individuals at tributary sites during MS2 in 2018 and
2019. PIT, passive integrated transponder.
Mean upstream swimming speed was 1.98 km day–1 for
females and 2.90 km day–1 for males, which was not
significantly different between sexes. However, downstream swimming
speed for females (5.68 km day–1) was more than
double that of males (2.63 km day–1) (t -test,P < 0.05). Travel time by the upstream migrants from
the river mouth to the mid-point of tributary sites was estimated to be
12.2 days (95% CI: 4.2–35.6 days) for females (Fig. 5) and 8.3 days
(95% CI: 1.9–36.1 days) for males.