Otolith Sr isotope values for Chinook salmon spawning in the Stanislaus River

The data file contains 87Sr/86Sr values measured in the otoliths of adult Chinook salmon sampled in the Stanislaus River, California, between 2001 and 2006. Fish age was estimated using scale annuli, and individuals that outmigrated in 2000 and 2003 were retained for the current analysis (see "Outmigration year"). Each otolith contains multiple 87Sr/86Sr values, representing spot analyses sampled along a standardized 90° transect from the otolith core towards the otolith edge. The average isotopic value of the natal region (post-exogenous feeding check) was used to assign river or hatchery of origin, and for individuals that originated in and returned to the Stanislaus River, the distance to the last natal spot (see "Distance from core") was used to estimate size at outmigration. The data file also includes the instrument error ("2SE"), strontium signal ("Sr (V)") and laser operating conditions associated with each spot analysis. See accompanying "README" file for additional information on each fish, including natal assignments.