Implementation of a Maternally Transferred Marker for Salmonids to Evaluate Supplementation

In this study, we will evaluate if strontium in solution could artificially elevate the Sr: Ca ratios in the otoliths of Oncorhynchus mykiss progeny by using an intra peritoneal cavity injection (IP) into pre-spawning adult female steelhead.  In addition to investigating whether Sr: Ca ratios become elevated with treatment, we will also assess population genetic structure of progeny from previous generations of juvenile steelhead and measure Sr: Ca ratios in otoliths to establish background information on the variation present. A deflection board weir near the mouth of Iskuulktpe creek, a tributary to the upper Umatilla River located in Eastern Oregon, will be used to capture and sample returning summer steelhead.  All fish captured will have a genetic clip taken for parentage analysis, with a subsample radio tagged.  All females will receive IP injection of 1cc/500 g body weight of a physiologically isotonic solution (0.9% saline) containing 0 mg/L (natural origin) or 20,000 mg/L (hatchery origin) of strontium chloride hexaydrate. IP injections containing strontium coupled with a pedigree analysis could be used to distinguish between the progeny of hatchery versus wild females that spawn naturally.  For example, in an integrated hatchery program where wild fish are subject for hatchery brood and hatchery fish are not, but are allowed to spawn in the wild.  If a female hatchery origin fish received a trans-generational mark and was fin clipped and released to spawn naturally, her offspring could then be distinguished from the offspring of wild females by analyzing their otolith microchemistry and pedigree.