Otolith ⁸⁷Sr/⁸⁶Sr reconstructions of a smolt and fry outmigrant.

<p>Otolith ⁸⁷Sr/⁸⁶Sr profiles against back-calculated FL for two adult Chinook salmon that returned to the Stanislaus River having outmigrated as (A) a smolt and (B) a fry. The shaded box indicates the time spent rearing in the natal river. The fry outmigrant reared for several weeks downstream in the San Joaquin River before migrating out to the ocean, as indicated by both the left (triangles, solid line) and right (circles, dashed line) otolith (back-calculated FL = 33.3mm <i>vs</i>. 34.9mm). Mean ⁸⁷Sr/⁸⁶Sr signatures for the Stanislaus and San Joaquin Rivers, and modern-day ocean are displayed. Black filled symbols indicate ‘re-spots’ carried out to improve sampling resolution. Error bars = 2SE.