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• 11. [Image] Fish caught at Crater Lake

  	Two rainbow trout caught in Crater Lake laid out on a rock.
  	Citation × Citation Citation Abstract Copy Title: Fish caught at Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two rainbow trout caught in Crater Lake laid out on a rock. Title: Fish caught at Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two rainbow trout caught in Crater Lake laid out on a rock. Close

• 12. [Image] Fishing on Crater Lake

  	A rainbow trout just being pulled out of the water by a fishing line on Crater Lake.
  	Citation × Citation Citation Abstract Copy Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 A rainbow trout just being pulled out of the water by a fishing line on Crater Lake. Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 A rainbow trout just being pulled out of the water by a fishing line on Crater Lake. Close

• 13. [Image] Fishing on Crater Lake

  	A man sitting in a rowboat on Crater Lake holding up a rainbow trout.
  	Citation × Citation Citation Abstract Copy Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 A man sitting in a rowboat on Crater Lake holding up a rainbow trout. Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 A man sitting in a rowboat on Crater Lake holding up a rainbow trout. Close

• 14. [Image] Fishing on Crater Lake

  	An unidentified man and woman in a rowboat on Crater Lake. The man is pulling a rainbow trout out of the water with a fishing pole.
  	Citation × Citation Citation Abstract Copy Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 An unidentified man and woman in a rowboat on Crater Lake. The man is pulling a rainbow trout out of the water with a fishing pole. Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 An unidentified man and woman in a rowboat on Crater Lake. The man is pulling a rainbow trout out of the water with a fishing pole. Close

• 15. [Image] Fishing on Crater Lake

  	Two men and two women in a rowboat on Crater Lake. One of the men is pulling a rainbow trout out of the water with a fishing pole.
  	Citation × Citation Citation Abstract Copy Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two men and two women in a rowboat on Crater Lake. One of the men is pulling a rainbow trout out of the water with a fishing pole. Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two men and two women in a rowboat on Crater Lake. One of the men is pulling a rainbow trout out of the water with a fishing pole. Close

• 16. [Image] Fishing on Crater Lake

  	Two men and two women in a rowboat on Crater Lake. One of the men is pulling a rainbow trout out of the water with a fishing pole.
  	Citation × Citation Citation Abstract Copy Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two men and two women in a rowboat on Crater Lake. One of the men is pulling a rainbow trout out of the water with a fishing pole. Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two men and two women in a rowboat on Crater Lake. One of the men is pulling a rainbow trout out of the water with a fishing pole. Close

• 17. [Article] Antioxidant enzyme response in rainbow trout (Oncorhynchus mykiss) after subchronic exposure to an environmentally-relevant polycyclic aromatic hydrocarbon mixture

  Polycyclic aromatic hydrocarbons (PAHs) are significant pollutants in aquatic environments. Many are carcinogenic and lead to DNA fragmentation and adduct formation in marine and freshwater organisms. ...

  Citation × Citation Citation Abstract Copy Title: Antioxidant enzyme response in rainbow trout (Oncorhynchus mykiss) after subchronic exposure to an environmentally-relevant polycyclic aromatic hydrocarbon mixture Author: Norby, Tyler S. Polycyclic aromatic hydrocarbons (PAHs) are significant pollutants in aquatic environments. Many are carcinogenic and lead to DNA fragmentation and adduct formation in marine and freshwater organisms. Previous research demonstrates that rainbow trout (Oncorhynchus mykiss) compensate to long-term PAH dietary exposures and reduce the DNA damage. The aim of this study was to assess whether upregulation of detoxifying/antioxidant enzymes in rainbow trout at least partially explains compensation to PAH exposure that allows for this reduction in DNA damage. Rainbow trout were fed a diet that contained a mixture of nine high molecular weight PAHs in environmentally relevant ratios and concentrations. Two doses were used: a lower dose of 20 parts per million (ppm) and a higher dose of 200 ppm. Two other treatment formulations were also used containing 20 ppm and 200 ppm concentrations of benzo(α)pyrene. A control group of rainbow trout was also used. 80 rainbow trout per PAH treatment and control were used in this experiment. The fish were fed PAH treatment diets or a control diet daily beginning when their average weight was 20 g. At days 7, 14, 28 and 42 enough fish were sacrificed from each of the four treatment groups plus control to obtain four 1 g pooled liver samples. Body and liver weights were recorded for each sacrificed fish. Various biomarkers and detoxifying/antioxidant enzyme activities were measured. Lipid peroxidation was estimated for all sample groups using a thiobarbituric acidreactive substances (TBARS) assay. NAD(P)H:quinone oxidoreductase 1 [DTdiaphorase], also known as quinone reductase (QR), activities were determined for all sample groups using a modified photometric assay that defines QR levels as the dicoumarol-inhibitable reduction of 2,6-dichlorophenolindophenol (DCPIP). Glutathione peroxidase (GPOX) activities were determined for all sample groups using a modified photometric assay that defines GPOX levels as the reduction of NADPH in cytosolic liver fractions. Catalase (CAT) activities were determined for all sample groups using an assay kit that utilized the reaction CAT has with methanol in the presence of hydrogen peroxide. CAT showed the strongest significant (P < 0.05) response, rising and falling over the time-course of the study in a dose-dependent sinusoidal decay pattern as the system moved toward optimal steady-state activity. GPOX activities increased significantly (P < 0.05) over the time-course of treatments, also showing a sinusoidal decay pattern similar to that seen with CAT, although the GPOX activity followed a slower decay pattern than CAT and was not dose-dependent. QR activities were low overall. This indicated that this detoxifying enzyme was not a major component of the trout’s adaptive response. The TBARS assay was determined to be an insensitive assay for fish tissues due to the harshness and unspecific nature of the test. The mass-spectroscopy-based F2-isoprostanes assay was determined to be a much more appropriate assay for the determination of lipid peroxide levels in fish tissues, based on previous research. Title: Antioxidant enzyme response in rainbow trout (Oncorhynchus mykiss) after subchronic exposure to an environmentally-relevant polycyclic aromatic hydrocarbon mixture Author: Norby, Tyler S. Polycyclic aromatic hydrocarbons (PAHs) are significant pollutants in aquatic environments. Many are carcinogenic and lead to DNA fragmentation and adduct formation in marine and freshwater organisms. Previous research demonstrates that rainbow trout (Oncorhynchus mykiss) compensate to long-term PAH dietary exposures and reduce the DNA damage. The aim of this study was to assess whether upregulation of detoxifying/antioxidant enzymes in rainbow trout at least partially explains compensation to PAH exposure that allows for this reduction in DNA damage. Rainbow trout were fed a diet that contained a mixture of nine high molecular weight PAHs in environmentally relevant ratios and concentrations. Two doses were used: a lower dose of 20 parts per million (ppm) and a higher dose of 200 ppm. Two other treatment formulations were also used containing 20 ppm and 200 ppm concentrations of benzo(α)pyrene. A control group of rainbow trout was also used. 80 rainbow trout per PAH treatment and control were used in this experiment. The fish were fed PAH treatment diets or a control diet daily beginning when their average weight was 20 g. At days 7, 14, 28 and 42 enough fish were sacrificed from each of the four treatment groups plus control to obtain four 1 g pooled liver samples. Body and liver weights were recorded for each sacrificed fish. Various biomarkers and detoxifying/antioxidant enzyme activities were measured. Lipid peroxidation was estimated for all sample groups using a thiobarbituric acidreactive substances (TBARS) assay. NAD(P)H:quinone oxidoreductase 1 [DTdiaphorase], also known as quinone reductase (QR), activities were determined for all sample groups using a modified photometric assay that defines QR levels as the dicoumarol-inhibitable reduction of 2,6-dichlorophenolindophenol (DCPIP). Glutathione peroxidase (GPOX) activities were determined for all sample groups using a modified photometric assay that defines GPOX levels as the reduction of NADPH in cytosolic liver fractions. Catalase (CAT) activities were determined for all sample groups using an assay kit that utilized the reaction CAT has with methanol in the presence of hydrogen peroxide. CAT showed the strongest significant (P < 0.05) response, rising and falling over the time-course of the study in a dose-dependent sinusoidal decay pattern as the system moved toward optimal steady-state activity. GPOX activities increased significantly (P < 0.05) over the time-course of treatments, also showing a sinusoidal decay pattern similar to that seen with CAT, although the GPOX activity followed a slower decay pattern than CAT and was not dose-dependent. QR activities were low overall. This indicated that this detoxifying enzyme was not a major component of the trout’s adaptive response. The TBARS assay was determined to be an insensitive assay for fish tissues due to the harshness and unspecific nature of the test. The mass-spectroscopy-based F2-isoprostanes assay was determined to be a much more appropriate assay for the determination of lipid peroxide levels in fish tissues, based on previous research. Close

• 18. [Image] Fishing on Crater Lake

  	Two unidentified men with fishing gear and several large fish standing on the rim of Crater Lake.
  	Citation × Citation Citation Abstract Copy Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two unidentified men with fishing gear and several large fish standing on the rim of Crater Lake. Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two unidentified men with fishing gear and several large fish standing on the rim of Crater Lake. Close

• 19. [Image] Fishing on Crater Lake

  	Two unidentified men with fishing gear standing on the rim of Crater Lake.
  	Citation × Citation Citation Abstract Copy Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two unidentified men with fishing gear standing on the rim of Crater Lake. Title: Fishing on Crater Lake Author: Finley, William L. (William Lovell), 1876-1953 Year: 1913 Two unidentified men with fishing gear standing on the rim of Crater Lake. Close

• 20. [Article] The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss

  The evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation ...

  Citation × Citation Citation Abstract Copy Title: The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss Author: Ohms, Haley The evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation of partially migratory species. In particular, why individuals adopt a particular phenotype has been the focus of numerous research efforts. In the partially migratory species Oncorhynchys mykiss (commonly known as steelhead and rainbow trout), I found that sex plays a strong role in whether an individual adopts an anadromous or resident life history. I observed a higher frequency of females adopting the anadromous tactic throughout the species range, and I attributed this to the relationship between body size and reproductive success in females that is not present in males. I did not observe differences in female bias along gradients of latitude or migration distance, and I hypothesize that while the frequency of tactics among populations may change along these gradients, either the change is equal between males and females, or an interaction of latitude and migration distance may control changes. I did not observe a corresponding male bias in the one resident population I sampled, and suggest that this is the result of a high frequency of residents in that population. I propose that sex ratios could be a valuable metric for measuring frequency of life-history tactics in populations and could facilitate the investigation into the controls of life-history tactics across broad scales. Title: The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss Author: Ohms, Haley The evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation of partially migratory species. In particular, why individuals adopt a particular phenotype has been the focus of numerous research efforts. In the partially migratory species Oncorhynchys mykiss (commonly known as steelhead and rainbow trout), I found that sex plays a strong role in whether an individual adopts an anadromous or resident life history. I observed a higher frequency of females adopting the anadromous tactic throughout the species range, and I attributed this to the relationship between body size and reproductive success in females that is not present in males. I did not observe differences in female bias along gradients of latitude or migration distance, and I hypothesize that while the frequency of tactics among populations may change along these gradients, either the change is equal between males and females, or an interaction of latitude and migration distance may control changes. I did not observe a corresponding male bias in the one resident population I sampled, and suggest that this is the result of a high frequency of residents in that population. I propose that sex ratios could be a valuable metric for measuring frequency of life-history tactics in populations and could facilitate the investigation into the controls of life-history tactics across broad scales. Close