Fig. 9. Changes in plasma levels of testosterone (T), 11-ketotestosterone (11KT), estradiol (E2) and 17-20β-dihydroxy-4-pregnen-3-one (DHP) during upstream migration in 2002. Pre-spawning and mature adults were collected along their homing pathway from the coast to the hatchery, as shown in Fig. 1B. Fish at or near the hatchery almost completed final maturation, so that they were considered as mature adults. Furthermore, data are compared with those from maturing adult I in the Bering Sea. Date of sampling and the number of fish are shown in Table 4. Value are means ± s.e.m. Significant differences among sampling points are identified with different letters (P<0.05 one-way ANOVA and Tukey's test). Asterisks indicate significant difference (P<0.05) when compared with the maturing adult 1 in the central Bering Sea.