FIGURE 5 The critical time windows of water temperature and water level
for female Sakhalin taimen (horizontal bars), and their average travel
time (i.e. departure timing) from the river mouth to the spawning ground
(vertical dashed line) with the 95% confidence interval (grey shading).
3.5 Social interactions during ascent and descent by
migrants
There were 19 comigrating pairs of female Sakhalin taimen ascending
through Site L during MS1, of which only two pairs entered the same
tributaries for spawning. This was less than half the number (4.9)
expected by chance, but the difference was not significant (P =
0.157, Table 2). Similarly, only three female pairs departed from the
same tributaries, out of 22 comigrating pairs descending through Site L
during MS4, which was half the expected number but also not significant
(P = 0.204). The numbers of male pairs of comigrating spawners
and post-spawners entering or departing from the same tributaries,
respectively, were not less than or greater than those expected by
chance (P > 0.05).
TABLE 2. Randomization test results of the social interaction
hypothesis, showing the observed numbers of comigrating pairs, and of
observed and simulated (mean ± SD) pairs that entered or departed from
the same tributaries.