Otolith 87Sr/86Sr reconstructions of a smolt and fry outmigrant.
figureposted on 2015-05-20, 04:19 authored by Anna M. Sturrock, J. D. Wikert, Timothy Heyne, Carl Mesick, Alan E. Hubbard, Travis M. Hinkelman, Peter K. Weber, George E. Whitman, Justin J. Glessner, Rachel C. Johnson
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 vs. 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.
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hydroclimatic regimelife history variationCalifornia Central Valleyfry contributionsJuvenile salmonMigratory Behavioradult spawnersContrasting Hydrologic Regimessmolt contributionsfry survivallife history traitsJuvenile Chinook Salmonrecovery effortsStanislaus Rivertaxonomic groupsadult Chinook salmonhydrologic regimepopulation sustainabilityoutmigrant timingoutmigration year 2000life history diversityusaflow regimesphenotypeJuvenile abundanceoutmigration behaviorOncorhynchus tshawytchaExtinction risk