In order to evaluate the survival of salmon produced artificially, it is necessary to mark the fry of hatchery spawning events (Schroder et al. 1994).  The consequences for marking millions of fry rapidly are labor intensive and sometimes impractical due to their size.  However, the authors provide a technique for marking millions of fish without individual handling by delivering a constant flow containing strontium to their rearing water.  Results from this study show an elevation in strontium by injecting mothers prior to egg fertilization.  Although the differences between treated and untreated fish are not as discrete as the studies using immersion baths (Shippentower unpublished data), the injection technique provides an opportunity for marking millions of eggs without individual handling.

In this study, we will evaluate if a strontium solution could artificially elevate the Sr: Ca ratios in the otoliths of O. mykiss progeny by using an intra peritoneal cavity injection of strontium chloride 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.  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 than be distinguished from the offspring of wild females by analyzing their otolith microchemistry and pedigree.

Ho: There is no difference in the relative reproductive success of hatchery versus wild female steelhead that spawns naturally in Iskuulpa Creek.

Ho: There is no difference in proportion of hatchery females (fin clipped) relative to wild females (no fin clip) returning to Three-mile Falls Dam located on the Umatilla River and Iskuulpa Creek.

Ho: There is no difference in Sr: Ca ratios collected from progeny of strontium treated and untreated females.

Ho: There is no relationship between water and otolith chemistries (Sr: Ca ratios) collected from Onchorhynchus mykiss parr and their natal stream.

Ho: A distinct genetic mark will identify progeny of females within and among each treatment group.

Ho: There is no difference in spawning distribution between hatchery and wild females.

Ho: There is no difference in the relative abundance of Onchorhynchus mykiss parr from strontium treated and untreated females in like physical habitat units.

Ho: There is no difference in the relative abundance of progeny from sympatric anadromous and non-anadromous Onchorhynchus mykiss in like physical habitat units.