Effects of Domestication on Predation Mortality and Competitive Dominance; Yakima/Klickitat Fisheries Project Monitoring and Evaluation Report 2 of 7, 2003-2004 Annual Report.

This report is intended to satisfy two concurrent needs: (1) provide a contract deliverable from the Washington Department of Fish and Wildlife (WDFW) to the Bonneville Power Administration (BPA), with emphasis on identification of salient results of value to ongoing Yakima/Klickitat Fisheries Project (YKFP) planning, and (2) summarize results of research that have broader scientific relevance. This is the second of a series of progress reports that address the effects of hatchery domestication on predation mortality and competitive dominance in the upper Yakima River basin (Pearsons et al. 2004). This progress report summarizes data collected between January 1, 2004 and December 31, 2004. Raising fish in hatcheries can cause unintended behavioral, physiological, or morphological changes in chinook salmon due to domestication selection. Domestication selection is defined by Busack and Currens 1995 as, ''changes in quantity, variety, or combination of alleles within a captive population or between a captive population and its source population in the wild as a result of selection in an artificial environment''. Selection in artificial environments could be due to intentional or artificial selection, biased sampling during some stage of culture, or unintentional selection (Busack and Currens 1995). Genetic changes can result in lowered survival in themore » natural environment (Reisenbichler and Rubin 1999). The goal of supplementation or conservation hatcheries is to produce fish that will integrate into natural populations. Conservation hatcheries attempt to minimize intentional or biased sampling so that the hatchery fish are similar to naturally produced fish. However, the selective pressures in hatcheries are dramatically different than in the wild, which can result in genetic differences between hatchery and wild fish. The selective pressures may be particularly prominent during the freshwater rearing stage where most mortality of wild fish occurs. The Yakima Fisheries Project is studying the effects of domestication on a variety of adult and juvenile traits of spring chinook salmon (Busack et al. 2003). The overall experimental design is to compare a variety of traits, across generations, from three lines of Yakima basin chinook, a hatchery control, supplementation line, and a wild control. The hatchery line was derived from wild upper Yakima broodstock and is only allowed to spawn in the hatchery. The supplementation line is upper Yakima stock that spawns in the upper Yakima River. This stock is an integration of wild and hatchery supplementation fish. Starting in 2005, we plan to use a wild control line of fish that will be the offspring of wild broodstock collected in the Naches River system, a tributary to the Yakima River. The Naches River is not stocked with hatchery fish, and there is minimal stray from Upper Yakima supplementation, so we believe that these will serve as a control to compare any genotypic changes in the hatchery and the supplementation line. As generations of fish are tested, we believe we will be able to analyze the data using an analysis of covariance to test the hypothesis that the hatchery line will exhibit greater domestication over generations, the wild line will remain at baseline levels, and the supplementation line will be somewhere in between. In this report, we have used the terms ''hatchery'' or ''supplementation'' to refer to upper Yakima fish that are progeny of fish that spent one generation in the hatchery, and ''wild'' to refer to fish that have had no exposure to the hatchery other than the matings for this experiment. The terms are relative to the parents that produced the fish for these experiments. All progeny of these fish were mated and reared under the same laboratory conditions. This report addresses two juvenile traits: predation mortality, and competitive dominance. Other traits will be presented in other project reports. It is anticipated that it will take at least two to five generations to detect measurable responses in many domestication response variables (Busack et al. 2003). This report addresses domestication after one generation of hatchery rearing. This report is organized into two chapters that represent major topics associated with monitoring hatchery domestication. Chapter 1 reports the results of domestication on predation mortality of juvenile spring chinook salmon. Chapter 2 describes the affects of domestication on competitive dominance of juvenile spring chinook salmon. The chapters in this report are in various stages of development and should be considered preliminary unless they have been published in a peer-reviewed journal. Additional field work and/or analysis is in progress for topics covered in this report. Throughout this report, a premium was placed on presenting data in tables so that other interested parties could have access to the data. « less