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• 31. [Article] Defining Conservation Priorities for Freshwater Fishes According to Taxonomic, Functional, and Phylogenetic Diversity

  To date, the predominant use of systematic conservation planning has been to evaluate and conserve areas of high terrestrial biodiversity. Although studies in freshwater ecosystems have received recent ...

  Citation × Citation Citation Abstract Copy Title: Defining Conservation Priorities for Freshwater Fishes According to Taxonomic, Functional, and Phylogenetic Diversity Author: Strecker, Angela L., Olden, Julian D., Whittier, Joanna B., Paukert, Craig Patrick Year: 2011 To date, the predominant use of systematic conservation planning has been to evaluate and conserve areas of high terrestrial biodiversity. Although studies in freshwater ecosystems have received recent attention, research has rarely considered the potential trade-offs between protecting different dimensions of biodiversity and the ecological processes that maintain diversity. We provide the first systematic prioritization for freshwaters (focusing on the highly threatened and globally distinct fish fauna of the Lower Colorado River Basin, USA) simultaneously considering scenarios of: taxonomic, functional, and phylogenetic diversity; contemporary threats to biodiversity (including interactions with nonnative species); and future climate change and human population growth. There was 75% congruence between areas of highest conservation priority for different aspects of biodiversity, suggesting that conservation efforts can concurrently achieve strong complementarity among all types of diversity. However, sizable fractions of the landscape were incongruent across conservation priorities for different diversity scenarios, underscoring the importance of considering multiple dimensions of biodiversity and highlighting catchments that contribute disproportionately to taxonomic, functional, and phylogenetic diversity in the region. Regions of projected human population growth were not concordant with conservation priorities; however, higher human population abundance will likely have indirect effects on native biodiversity by increasing demand for water. This will come in direct conflict with projected reductions in precipitation and warmer temperatures, which have substantial overlap with regions of high contemporary diversity. Native and endemic fishes in arid ecosystems are critically endangered by both current and future threats, but our results highlight the use of systematic conservation planning for the optimal allocation of limited resources that incorporates multiple and complementary conservation values describing taxonomic, functional, and phylogenetic diversity. Title: Defining Conservation Priorities for Freshwater Fishes According to Taxonomic, Functional, and Phylogenetic Diversity Author: Strecker, Angela L., Olden, Julian D., Whittier, Joanna B., Paukert, Craig Patrick Year: 2011 To date, the predominant use of systematic conservation planning has been to evaluate and conserve areas of high terrestrial biodiversity. Although studies in freshwater ecosystems have received recent attention, research has rarely considered the potential trade-offs between protecting different dimensions of biodiversity and the ecological processes that maintain diversity. We provide the first systematic prioritization for freshwaters (focusing on the highly threatened and globally distinct fish fauna of the Lower Colorado River Basin, USA) simultaneously considering scenarios of: taxonomic, functional, and phylogenetic diversity; contemporary threats to biodiversity (including interactions with nonnative species); and future climate change and human population growth. There was 75% congruence between areas of highest conservation priority for different aspects of biodiversity, suggesting that conservation efforts can concurrently achieve strong complementarity among all types of diversity. However, sizable fractions of the landscape were incongruent across conservation priorities for different diversity scenarios, underscoring the importance of considering multiple dimensions of biodiversity and highlighting catchments that contribute disproportionately to taxonomic, functional, and phylogenetic diversity in the region. Regions of projected human population growth were not concordant with conservation priorities; however, higher human population abundance will likely have indirect effects on native biodiversity by increasing demand for water. This will come in direct conflict with projected reductions in precipitation and warmer temperatures, which have substantial overlap with regions of high contemporary diversity. Native and endemic fishes in arid ecosystems are critically endangered by both current and future threats, but our results highlight the use of systematic conservation planning for the optimal allocation of limited resources that incorporates multiple and complementary conservation values describing taxonomic, functional, and phylogenetic diversity. Close

• 32. [Article] Archaeological Data Provide Alternative Hypotheses on Pacific Herring (Clupea pallasii) Distribution, Abundance, and Variability

  Over the last century, Pacific herring, a forage fish of tremendous cultural, economic, and ecological importance, has declined in abundance over much of its range. We synthesize archaeological fisheries ...

  Citation × Citation Citation Abstract Copy Title: Archaeological Data Provide Alternative Hypotheses on Pacific Herring (Clupea pallasii) Distribution, Abundance, and Variability Author: McKechnie, Iain, Lepofsky, Dana, Moss, Madonna L., Butler, Virginia L., Orchard, Trevor J, Coupland, Gary, Foster, Frederick, Caldwell, Megan, Lertzman, Ken Year: 2014 Over the last century, Pacific herring, a forage fish of tremendous cultural, economic, and ecological importance, has declined in abundance over much of its range. We synthesize archaeological fisheries data spanning the past 10,000 y from Puget Sound in Washington to southeast Alaska to extend the ecological baseline for herring and contextualize the dynamics of modern industrial fisheries. While modern herring populations can be erratic and exhibit catastrophic declines, the archaeological record indicates a pattern of consistent abundance, providing an example of long-term sustainability and resilience in a fishery known for its modern variability. The most parsimonious explanation for the discrepancy between herring abundance in the ancient and more recent past is industrial harvesting over the last century. Title: Archaeological Data Provide Alternative Hypotheses on Pacific Herring (Clupea pallasii) Distribution, Abundance, and Variability Author: McKechnie, Iain, Lepofsky, Dana, Moss, Madonna L., Butler, Virginia L., Orchard, Trevor J, Coupland, Gary, Foster, Frederick, Caldwell, Megan, Lertzman, Ken Year: 2014 Over the last century, Pacific herring, a forage fish of tremendous cultural, economic, and ecological importance, has declined in abundance over much of its range. We synthesize archaeological fisheries data spanning the past 10,000 y from Puget Sound in Washington to southeast Alaska to extend the ecological baseline for herring and contextualize the dynamics of modern industrial fisheries. While modern herring populations can be erratic and exhibit catastrophic declines, the archaeological record indicates a pattern of consistent abundance, providing an example of long-term sustainability and resilience in a fishery known for its modern variability. The most parsimonious explanation for the discrepancy between herring abundance in the ancient and more recent past is industrial harvesting over the last century. Close

• 33. [Article] The Role of Salmon in Middle Snake River Human Economy: The Hetrick Site in Regional Contexts

  On the Columbia Plateau, the origin of the Winter Village Pattern has long been a focus of research. Intensification of resources such as salmon, roots, and local aquatic resources is often cited as the ...

  Citation × Citation Citation Abstract Copy Title: The Role of Salmon in Middle Snake River Human Economy: The Hetrick Site in Regional Contexts Author: Manning, Cassandra R. Year: 2011 On the Columbia Plateau, the origin of the Winter Village Pattern has long been a focus of research. Intensification of resources such as salmon, roots, and local aquatic resources is often cited as the cause of declining mobility. To address this question in the middle Snake River region, I have re-analyzed fish remains from the Hetrick site (10WN469; Weiser, ID), with occupations spanning the Holocene. Expectations from foraging theory and paleoclimate data are used to address whether salmon and other fish use changed over time and if such changes are correlated with the development of the Winter Village Pattern. The results of my research indicate that there is no correlation between the timing of increased salmonid use at the Hetrick site and paleoclimatic change or the earliest evidence for the Winter Village Pattern. Further, these results are very similar to patterns of fish use seen at other sites on the Snake River, particularly those from the Early and Middle Holocene. Title: The Role of Salmon in Middle Snake River Human Economy: The Hetrick Site in Regional Contexts Author: Manning, Cassandra R. Year: 2011 On the Columbia Plateau, the origin of the Winter Village Pattern has long been a focus of research. Intensification of resources such as salmon, roots, and local aquatic resources is often cited as the cause of declining mobility. To address this question in the middle Snake River region, I have re-analyzed fish remains from the Hetrick site (10WN469; Weiser, ID), with occupations spanning the Holocene. Expectations from foraging theory and paleoclimate data are used to address whether salmon and other fish use changed over time and if such changes are correlated with the development of the Winter Village Pattern. The results of my research indicate that there is no correlation between the timing of increased salmonid use at the Hetrick site and paleoclimatic change or the earliest evidence for the Winter Village Pattern. Further, these results are very similar to patterns of fish use seen at other sites on the Snake River, particularly those from the Early and Middle Holocene. Close

• 34. [Article] Aboriginal Fisheries of the Lower Columbia River

  This chapter, included in Chinookan Peoples of the Lower Columbia, published by the University of Washington Press in 2013, explores the aboriginal fisheries of the Lower Columbia River. The authors reviewed ...

  Citation × Citation Citation Abstract Copy Title: Aboriginal Fisheries of the Lower Columbia River Author: Butler, Virginia L., Martin, Michael A. Year: 2013 This chapter, included in Chinookan Peoples of the Lower Columbia, published by the University of Washington Press in 2013, explores the aboriginal fisheries of the Lower Columbia River. The authors reviewed ethnohistorical accounts and studies of archaeological sites to create a complex picture of Columbia River fisheries that challenges the prevailing view among anthropologists that salmon was the primary and predominant fishery among Chinookan peoples. The authors show that 19th century Native fishers targeted virtually all native fish species in the Lower Columbia River, and employed a wide range of strategies and tactics to acquire and process fish. Title: Aboriginal Fisheries of the Lower Columbia River Author: Butler, Virginia L., Martin, Michael A. Year: 2013 This chapter, included in Chinookan Peoples of the Lower Columbia, published by the University of Washington Press in 2013, explores the aboriginal fisheries of the Lower Columbia River. The authors reviewed ethnohistorical accounts and studies of archaeological sites to create a complex picture of Columbia River fisheries that challenges the prevailing view among anthropologists that salmon was the primary and predominant fishery among Chinookan peoples. The authors show that 19th century Native fishers targeted virtually all native fish species in the Lower Columbia River, and employed a wide range of strategies and tactics to acquire and process fish. Close

• 35. [Article] On the Validity of the Radiographic Method for Determining Age of Ancient Salmon

  White rings visible on the centrum face of salmon vertebrae with X-rays have been used since the 1980s to age Pacific salmon (Oncorhynchus spp.), which in turn have been used to determine salmon species, ...

  Citation × Citation Citation Abstract Copy Title: On the Validity of the Radiographic Method for Determining Age of Ancient Salmon Author: Hofkamp, Anthony R., Butler, Virginia L. Year: 2017 White rings visible on the centrum face of salmon vertebrae with X-rays have been used since the 1980s to age Pacific salmon (Oncorhynchus spp.), which in turn have been used to determine salmon species, season of capture and season of site occupation. This approach relies on a variety of assumptions, the most fundamental of which is that rings represent true years. Recent aDNA analysis has shown that the X-ray approach has flaws but the source of the error has been unknown. Given the value of reconstructing salmon population demographics and life history from ancient remains, establishing a valid and reliable method of ageing salmon vertebrae is extremely worthwhile. The main goal of our study was to evaluate if X-ray images of ring patterns on vertebrae provide a valid method of estimating fish age. Vertebrae from 66 adult Chinook salmon (O. tshawytscha) of known age were studied with X-rays, thin sections or low-powered (10–30 ×) magnification. We found that the white bands observed in X-rays are structural walls that do not grow annually. While X-rays are not a valid method for ageing salmonids, incremental growth seen on the surface of fish centra shows great promise for reconstructing ancient fish life history. Title: On the Validity of the Radiographic Method for Determining Age of Ancient Salmon Author: Hofkamp, Anthony R., Butler, Virginia L. Year: 2017 White rings visible on the centrum face of salmon vertebrae with X-rays have been used since the 1980s to age Pacific salmon (Oncorhynchus spp.), which in turn have been used to determine salmon species, season of capture and season of site occupation. This approach relies on a variety of assumptions, the most fundamental of which is that rings represent true years. Recent aDNA analysis has shown that the X-ray approach has flaws but the source of the error has been unknown. Given the value of reconstructing salmon population demographics and life history from ancient remains, establishing a valid and reliable method of ageing salmon vertebrae is extremely worthwhile. The main goal of our study was to evaluate if X-ray images of ring patterns on vertebrae provide a valid method of estimating fish age. Vertebrae from 66 adult Chinook salmon (O. tshawytscha) of known age were studied with X-rays, thin sections or low-powered (10–30 ×) magnification. We found that the white bands observed in X-rays are structural walls that do not grow annually. While X-rays are not a valid method for ageing salmonids, incremental growth seen on the surface of fish centra shows great promise for reconstructing ancient fish life history. Close

• 36. [Article] Desert Environments

  This is a book chapter within Extremophile Fishes. This book summarizes the key adaptations enabling extremophile fishes to survive under harsh environmental conditions. It reviews the most recent research ...

  Citation × Citation Citation Abstract Copy Title: Desert Environments Author: Hillyard, Stanley D., Podrabsky, Jason E., van Breukelen, Frank Year: 2015 This is a book chapter within Extremophile Fishes. This book summarizes the key adaptations enabling extremophile fishes to survive under harsh environmental conditions. It reviews the most recent research on acidic, Antarctic, cave, desert, hypersaline, hypoxic, temporary, and fast-flowing habitats, as well as naturally and anthropogenically toxic waters, while pointing out generalities that are evident across different study systems. Knowledge of the different adaptations that allow fish to cope with stressful environmental conditions furthers our understanding of basic physiological, ecological, and evolutionary principles. In several cases, evidence is provided for how the adaptation to extreme environments promotes the emergence of new species. Furthermore, a link is made to conservation biology, and how human activities have exacerbated existing extreme environments and created new ones. The book concludes with a discussion of major open questions in our understanding of the ecology and evolution of life in extreme environments. Title: Desert Environments Author: Hillyard, Stanley D., Podrabsky, Jason E., van Breukelen, Frank Year: 2015 This is a book chapter within Extremophile Fishes. This book summarizes the key adaptations enabling extremophile fishes to survive under harsh environmental conditions. It reviews the most recent research on acidic, Antarctic, cave, desert, hypersaline, hypoxic, temporary, and fast-flowing habitats, as well as naturally and anthropogenically toxic waters, while pointing out generalities that are evident across different study systems. Knowledge of the different adaptations that allow fish to cope with stressful environmental conditions furthers our understanding of basic physiological, ecological, and evolutionary principles. In several cases, evidence is provided for how the adaptation to extreme environments promotes the emergence of new species. Furthermore, a link is made to conservation biology, and how human activities have exacerbated existing extreme environments and created new ones. The book concludes with a discussion of major open questions in our understanding of the ecology and evolution of life in extreme environments. Close

• 37. [Article] A System Dynamics Model of the Pacific Coast Rockfish Fishery

  This paper presents a model of the dynamic behavior of the yellowtail rockfish of the Pacific Coast of the United States. The purpose of the model is to generate endogenously the historical data for fish ...

  Citation × Citation Citation Abstract Copy Title: A System Dynamics Model of the Pacific Coast Rockfish Fishery Author: Wakeland, Wayne, Cangur, Olgay, Rueda, Guillermo, Scholz, Astrid Year: 2003 This paper presents a model of the dynamic behavior of the yellowtail rockfish of the Pacific Coast of the United States. The purpose of the model is to generate endogenously the historical data for fish population, fishing vessels, regulatory parameters, and fish harvest. The model was subjected to a variety of tests to determine its sensitivity to changes in key parameters and initial values, including extreme conditions. Model results indicate that acceptable biological catch and fleet capacity must be adjusted quickly in response to changing conditions, in order to improve fishery sustainability. Additional analysis reinforces the policy of setting the maximum sustainable yield at 40%. Title: A System Dynamics Model of the Pacific Coast Rockfish Fishery Author: Wakeland, Wayne, Cangur, Olgay, Rueda, Guillermo, Scholz, Astrid Year: 2003 This paper presents a model of the dynamic behavior of the yellowtail rockfish of the Pacific Coast of the United States. The purpose of the model is to generate endogenously the historical data for fish population, fishing vessels, regulatory parameters, and fish harvest. The model was subjected to a variety of tests to determine its sensitivity to changes in key parameters and initial values, including extreme conditions. Model results indicate that acceptable biological catch and fleet capacity must be adjusted quickly in response to changing conditions, in order to improve fishery sustainability. Additional analysis reinforces the policy of setting the maximum sustainable yield at 40%. Close

• 38. [Article] Expression of Growth Arrest and DNA Damage Protein 45-alpha (gadd45-alpha) and the CCAAT/enhancer binding protein-delta (C/EBP-delta) in Fishes Exposed to Heat and Hypoxia

  The cellular stress response (CSR) is one of the most highly conserved mechanisms among all organisms. Cellular stress can be defined as damage or the threat of damage to proteins, macromolecules and/or ...

  Citation × Citation Citation Abstract Copy Title: Expression of Growth Arrest and DNA Damage Protein 45-alpha (gadd45-alpha) and the CCAAT/enhancer binding protein-delta (C/EBP-delta) in Fishes Exposed to Heat and Hypoxia Author: Hassumani, Daniel Omar Year: 2013 The cellular stress response (CSR) is one of the most highly conserved mechanisms among all organisms. Cellular stress can be defined as damage or the threat of damage to proteins, macromolecules and/or DNA. The response to damage can involve cell cycle regulation, protein chaperoning, DNA repair or, if macromolecular damage is too severe, apoptotic mechanisms can be initiated. This thesis details experiments that were designed to examine the cellular response to non-lethal environmental stressors at the protein level, using two fish species as study models. Two proteins that can cause cell cycle arrest and apoptosis mechanisms were examined. Expression of the CCAAT enhancer binding protein-delta (C/EBP-[delta]) was examined in the zebrafish, Danio rerio, exposed to acute, non-lethal hypoxic conditions. While C/EBP-[delta] was expressed constitutively in control individuals during all time points, exposure to hypoxic conditions did not have a consistent significant effect on C/EBP-[delta] expression (two-way ANOVA, P>0.05) in zebrafish white muscle tissue. In a second study, the expression of the growth arrest and DNA damage 45-alpha protein (gadd45-[alpha], a mediator of cell cycle arrest and perhaps apoptosis was examined in heat-stressed liver tissue of an extremely cold-adapted Antarctic fish, Trematomus bernacchii. Gadd45-[alpha] levels were higher in fish exposure to 2°C across all time points (one-way ANOVA; P Title: Expression of Growth Arrest and DNA Damage Protein 45-alpha (gadd45-alpha) and the CCAAT/enhancer binding protein-delta (C/EBP-delta) in Fishes Exposed to Heat and Hypoxia Author: Hassumani, Daniel Omar Year: 2013 The cellular stress response (CSR) is one of the most highly conserved mechanisms among all organisms. Cellular stress can be defined as damage or the threat of damage to proteins, macromolecules and/or DNA. The response to damage can involve cell cycle regulation, protein chaperoning, DNA repair or, if macromolecular damage is too severe, apoptotic mechanisms can be initiated. This thesis details experiments that were designed to examine the cellular response to non-lethal environmental stressors at the protein level, using two fish species as study models. Two proteins that can cause cell cycle arrest and apoptosis mechanisms were examined. Expression of the CCAAT enhancer binding protein-delta (C/EBP-[delta]) was examined in the zebrafish, Danio rerio, exposed to acute, non-lethal hypoxic conditions. While C/EBP-[delta] was expressed constitutively in control individuals during all time points, exposure to hypoxic conditions did not have a consistent significant effect on C/EBP-[delta] expression (two-way ANOVA, P>0.05) in zebrafish white muscle tissue. In a second study, the expression of the growth arrest and DNA damage 45-alpha protein (gadd45-[alpha], a mediator of cell cycle arrest and perhaps apoptosis was examined in heat-stressed liver tissue of an extremely cold-adapted Antarctic fish, Trematomus bernacchii. Gadd45-[alpha] levels were higher in fish exposure to 2°C across all time points (one-way ANOVA; P Close

• 39. [Article] Tracking Fish and Human Response to Abrupt Environmental Change at Tse-whit-zen: A Large Native American Village on the Olympic Peninsula, Washington State

  Evidence of large earthquakes occurring along the Pacific Northwest coast is reflected in coastal stratigraphy from Oregon to British Columbia, where there also exists an extensive archaeological record ...

  Citation × Citation Citation Abstract Copy Title: Tracking Fish and Human Response to Abrupt Environmental Change at Tse-whit-zen: A Large Native American Village on the Olympic Peninsula, Washington State Author: Mohlenhoff, Kathryn Anne Year: 2013 Evidence of large earthquakes occurring along the Pacific Northwest coast is reflected in coastal stratigraphy from Oregon to British Columbia, where there also exists an extensive archaeological record of Native American occupation. Tse-whit-zen, a large Native American village dating between 1824 and 54 cal B.P. located on the Olympic Peninsula of Washington State, was excavated with exceptionally fine stratigraphic control allowing for precise comparison of natural and cultural records. Here I report on the >10,000 fish remains from one 2x2 m excavation block; this assemblage spans one earthquake event, allowing study of changes in relative taxonomic abundance through time that may coincide with earthquakes or other environmental changes. Results indicate use of a wide range of marine fish taxa including various sculpins (Cottidae), flatfish (Pleuronectiformes), herring (Clupea pallasii) and salmon (Oncorhynchusspp.). This illustrates a highly diverse diet throughout occupation, though relative abundances of more offshore taxa decrease through time in favor of some nearshore taxa, possibly indicating the presence of a coseismic event. This thesis serves as part of a pilot study for a collaborative project that is underway. This larger project addresses human response to both gradual and abrupt environmental change through the analysis of all classes of Tse-whit-zen faunal remains, which provide a link to impacts on animal populations and in turn human subsistence. Title: Tracking Fish and Human Response to Abrupt Environmental Change at Tse-whit-zen: A Large Native American Village on the Olympic Peninsula, Washington State Author: Mohlenhoff, Kathryn Anne Year: 2013 Evidence of large earthquakes occurring along the Pacific Northwest coast is reflected in coastal stratigraphy from Oregon to British Columbia, where there also exists an extensive archaeological record of Native American occupation. Tse-whit-zen, a large Native American village dating between 1824 and 54 cal B.P. located on the Olympic Peninsula of Washington State, was excavated with exceptionally fine stratigraphic control allowing for precise comparison of natural and cultural records. Here I report on the >10,000 fish remains from one 2x2 m excavation block; this assemblage spans one earthquake event, allowing study of changes in relative taxonomic abundance through time that may coincide with earthquakes or other environmental changes. Results indicate use of a wide range of marine fish taxa including various sculpins (Cottidae), flatfish (Pleuronectiformes), herring (Clupea pallasii) and salmon (Oncorhynchusspp.). This illustrates a highly diverse diet throughout occupation, though relative abundances of more offshore taxa decrease through time in favor of some nearshore taxa, possibly indicating the presence of a coseismic event. This thesis serves as part of a pilot study for a collaborative project that is underway. This larger project addresses human response to both gradual and abrupt environmental change through the analysis of all classes of Tse-whit-zen faunal remains, which provide a link to impacts on animal populations and in turn human subsistence. Close

• 40. [Article] Gene Expression Life History Markers in a Hatchery and a Wild Population of Young-of-the-Year Oncorhynchus mykiss

  Life history within a single species can vary significantly. Many of these differences are associated with varying environmental conditions. Understanding what environmental conditions cue alternate life ...

  Citation × Citation Citation Abstract Copy Title: Gene Expression Life History Markers in a Hatchery and a Wild Population of Young-of-the-Year Oncorhynchus mykiss Author: Garrett, Ian D. F. Year: 2013 Life history within a single species can vary significantly. Many of these differences are associated with varying environmental conditions. Understanding what environmental conditions cue alternate life histories within a single species has been researched extensively. In salmonid fishes, more than almost any other group, varying environmental conditions give rise to individuals within species that take markedly different life history trajectories. Oncorhynchus mykissis a species of salmonid native to the Pacific Northwest region of North America. This species has two life history forms, anadromous and resident. The anadromous form spends a portion of its life in ocean while the resident life history form completes its entire life history in freshwater. Until the decision to migrate and morphological changes associated with smoltification occur, the two life history variants of this species are indistinguishable from each other. This ambiguity in juvenile O. mykiss morphology presents challenges for conservation managers charged with protecting and increasing threatened O. mykiss populations around the Pacific Northwest because conservation efforts cannot be evaluated until juvenile fish make the decision to migrate. Microarray gene expression analysis was used to profile gene expression in juvenile populations of wild and hatchery O. mykiss to identify gene expression variation associated with alternate life history variants. This analysis identified 8 DNA sequences present in both brain and gill tissues that differ in expression in rainbow trout and steelhead hatchery stocks. Differential expression as quantified by microarrays was validated with quantitative real-time PCR. Lastly, the expression of these putative life history markers was preliminarily evaluated in a wild population of O. mykiss at sample locations in the South Fork John Day River Basin, Oregon with known ratios of juvenile anadromous and resident fish. Title: Gene Expression Life History Markers in a Hatchery and a Wild Population of Young-of-the-Year Oncorhynchus mykiss Author: Garrett, Ian D. F. Year: 2013 Life history within a single species can vary significantly. Many of these differences are associated with varying environmental conditions. Understanding what environmental conditions cue alternate life histories within a single species has been researched extensively. In salmonid fishes, more than almost any other group, varying environmental conditions give rise to individuals within species that take markedly different life history trajectories. Oncorhynchus mykissis a species of salmonid native to the Pacific Northwest region of North America. This species has two life history forms, anadromous and resident. The anadromous form spends a portion of its life in ocean while the resident life history form completes its entire life history in freshwater. Until the decision to migrate and morphological changes associated with smoltification occur, the two life history variants of this species are indistinguishable from each other. This ambiguity in juvenile O. mykiss morphology presents challenges for conservation managers charged with protecting and increasing threatened O. mykiss populations around the Pacific Northwest because conservation efforts cannot be evaluated until juvenile fish make the decision to migrate. Microarray gene expression analysis was used to profile gene expression in juvenile populations of wild and hatchery O. mykiss to identify gene expression variation associated with alternate life history variants. This analysis identified 8 DNA sequences present in both brain and gill tissues that differ in expression in rainbow trout and steelhead hatchery stocks. Differential expression as quantified by microarrays was validated with quantitative real-time PCR. Lastly, the expression of these putative life history markers was preliminarily evaluated in a wild population of O. mykiss at sample locations in the South Fork John Day River Basin, Oregon with known ratios of juvenile anadromous and resident fish. Close