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• 31. [Article] Effects of juvenile steelhead on juvenile chinook salmon behavior and physiology

  Experiments were designed to determine whether and how steelhead Oncorhynchus mykiss affect chinook salmon O. tshawytscha when the two species are confined together. In a behavioral experiment, we observed ...

  Citation × Citation Citation Abstract Copy Title: Effects of juvenile steelhead on juvenile chinook salmon behavior and physiology Author: Schreck, Carl B., Congleton, J. L., Kelsey, D. A., Davis, L. E. Experiments were designed to determine whether and how steelhead Oncorhynchus mykiss affect chinook salmon O. tshawytscha when the two species are confined together. In a behavioral experiment, we observed groups of juvenile chinook salmon and steelhead together and groups of chinook salmon alone to determine whether the steelhead were aggressive and their presence changed the behavior of chinook salmon. We also performed two runs of a physiological experiment to determine whether the addition of steelhead to tanks containing chinook salmon would stress the chinook salmon, as determined by a change in their plasma cortisol levels. Behavioral changes were observed in the chinook salmon when they were held with steelhead; they reduced their movements, darted less, were attacked up to 16 times as often, and were found less frequently in the shade than chinook salmon held without steelhead. Steelhead were found to establish territories and defend them with chases, charges, and nips. In their attempts to establish and defend territories, the steelhead attacked the chinook salmon as often as they attacked other steelhead, but the chinook salmon showed little aggression toward the steelhead. Cortisol concentrations were significantly higher for chinook salmon in tanks receiving steelhead than in tanks receiving additional chinook salmon or no additional fish after 2 h (in one of the two experimental runs) and after 32 h (in both experimental runs; combined data). These results suggest that confining steelhead and chinook salmon together, such as in raceways and barges in the Columbia River system and in other situations, is stressful to the chinook salmon. Title: Effects of juvenile steelhead on juvenile chinook salmon behavior and physiology Author: Schreck, Carl B., Congleton, J. L., Kelsey, D. A., Davis, L. E. Experiments were designed to determine whether and how steelhead Oncorhynchus mykiss affect chinook salmon O. tshawytscha when the two species are confined together. In a behavioral experiment, we observed groups of juvenile chinook salmon and steelhead together and groups of chinook salmon alone to determine whether the steelhead were aggressive and their presence changed the behavior of chinook salmon. We also performed two runs of a physiological experiment to determine whether the addition of steelhead to tanks containing chinook salmon would stress the chinook salmon, as determined by a change in their plasma cortisol levels. Behavioral changes were observed in the chinook salmon when they were held with steelhead; they reduced their movements, darted less, were attacked up to 16 times as often, and were found less frequently in the shade than chinook salmon held without steelhead. Steelhead were found to establish territories and defend them with chases, charges, and nips. In their attempts to establish and defend territories, the steelhead attacked the chinook salmon as often as they attacked other steelhead, but the chinook salmon showed little aggression toward the steelhead. Cortisol concentrations were significantly higher for chinook salmon in tanks receiving steelhead than in tanks receiving additional chinook salmon or no additional fish after 2 h (in one of the two experimental runs) and after 32 h (in both experimental runs; combined data). These results suggest that confining steelhead and chinook salmon together, such as in raceways and barges in the Columbia River system and in other situations, is stressful to the chinook salmon. Close

• 32. [Article] Salmon blood plasma: Effective inhibitor of protease-laden Pacific whiting surimi and salmon mince

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/food-chemistry/

  Citation × Citation Citation Abstract Copy Title: Salmon blood plasma: Effective inhibitor of protease-laden Pacific whiting surimi and salmon mince Author: Park, Jae W., Fowler, Matthew R. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/food-chemistry/ Title: Salmon blood plasma: Effective inhibitor of protease-laden Pacific whiting surimi and salmon mince Author: Park, Jae W., Fowler, Matthew R. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/food-chemistry/ Close

• 33. [Article] The effect of trade liberation on the salmon market in Finland

  Research Paper

  Citation × Citation Citation Abstract Copy Title: The effect of trade liberation on the salmon market in Finland Author: Honkanen, Asmo, Virtanen, Jarno, Setala, Jari, Mickwitz, Per, Saarni, Kaija Research Paper Title: The effect of trade liberation on the salmon market in Finland Author: Honkanen, Asmo, Virtanen, Jarno, Setala, Jari, Mickwitz, Per, Saarni, Kaija Research Paper Close

• 34. [Article] A demand analysis of processed salmon from the West Coast

  The primary purpose of the study was to identify the demand for processed salmon from the West Coast. The basic approach in the demand analysis was to identify those variables that determine the supply ...

  Citation × Citation Citation Abstract Copy Title: A demand analysis of processed salmon from the West Coast Author: Wood, William Robert The primary purpose of the study was to identify the demand for processed salmon from the West Coast. The basic approach in the demand analysis was to identify those variables that determine the supply and demand for processed salmon. An econometric model was established containing the supply and demand equations from which estimates for the parameters in each equation were obtained. The main source of data for salmon was obtained from publications printed by the Bureau of Commercial Fisheries, and the Pacific Fisherman. Ordinary least squares using the wholesale price as the dependent variable in the demand equation was the principal method of analysis. Coefficients for the demand expressed flexibilities with respect to the price. Price flexibilities calculated at the mean values for all processed salmon indicated that a ten percent increase in volume would reduce price by a lesser percentage. For increases in the supply of processed salmon, total revenues would increase, where decreases in supply would cause total revenues to decline. The results of the study also indicated that for a small percentage increase in disposable income, prices would increase but by a lesser percentage. Inverse relationships were noted between the price of salmon and the quantity of canned meat and meat products. Effects of population changes on the price of processed salmon were inconclusive. Title: A demand analysis of processed salmon from the West Coast Author: Wood, William Robert The primary purpose of the study was to identify the demand for processed salmon from the West Coast. The basic approach in the demand analysis was to identify those variables that determine the supply and demand for processed salmon. An econometric model was established containing the supply and demand equations from which estimates for the parameters in each equation were obtained. The main source of data for salmon was obtained from publications printed by the Bureau of Commercial Fisheries, and the Pacific Fisherman. Ordinary least squares using the wholesale price as the dependent variable in the demand equation was the principal method of analysis. Coefficients for the demand expressed flexibilities with respect to the price. Price flexibilities calculated at the mean values for all processed salmon indicated that a ten percent increase in volume would reduce price by a lesser percentage. For increases in the supply of processed salmon, total revenues would increase, where decreases in supply would cause total revenues to decline. The results of the study also indicated that for a small percentage increase in disposable income, prices would increase but by a lesser percentage. Inverse relationships were noted between the price of salmon and the quantity of canned meat and meat products. Effects of population changes on the price of processed salmon were inconclusive. Close

• 35. [Article] When Celilo was Celilo : an analysis of salmon use during the past 11,000 years in the Columbia Plateau

  The presence and significance of salmon for prehistoric and aboriginal people of the Columbia Plateau is a matter of considerable debate among anthropologists, archaeologists and historians. Data from ...

  Citation × Citation Citation Abstract Copy Title: When Celilo was Celilo : an analysis of salmon use during the past 11,000 years in the Columbia Plateau Author: Thomison, Patrick The presence and significance of salmon for prehistoric and aboriginal people of the Columbia Plateau is a matter of considerable debate among anthropologists, archaeologists and historians. Data from over 100 archaeological sites are scrutinized in the light of an example salmon fishery developed from ethnographic and archaeological information on aboriginal salmon dependencies and exploitation in the locale of The Dalles on the central Columbia. The research incorporates a cultural ecology orientation. Data from prehistoric sites of the Columbia Plateau do not conform precisely to The Dalles fishery example and strongly suggest both a temporal and spatial variation in salmon use and cultural patterning and therefore call to question the presumption of the primary relevancy of salmon to cultural patterning throughout the Plateau. Other resources, including especially botanical species, appear to have an importance too often overlooked. Other riverine and terrestrial mammal food resources are presumed to have a lesser prehistoric importance, though the archaeological record actually supports the importance of resources other than salmon as having pervasive affects on cultural patterning in the Columbia Plateau. Data show that it was not until recent times that salmon occurrence had the effect on cultural systems that has been observed in historic times. Title: When Celilo was Celilo : an analysis of salmon use during the past 11,000 years in the Columbia Plateau Author: Thomison, Patrick The presence and significance of salmon for prehistoric and aboriginal people of the Columbia Plateau is a matter of considerable debate among anthropologists, archaeologists and historians. Data from over 100 archaeological sites are scrutinized in the light of an example salmon fishery developed from ethnographic and archaeological information on aboriginal salmon dependencies and exploitation in the locale of The Dalles on the central Columbia. The research incorporates a cultural ecology orientation. Data from prehistoric sites of the Columbia Plateau do not conform precisely to The Dalles fishery example and strongly suggest both a temporal and spatial variation in salmon use and cultural patterning and therefore call to question the presumption of the primary relevancy of salmon to cultural patterning throughout the Plateau. Other resources, including especially botanical species, appear to have an importance too often overlooked. Other riverine and terrestrial mammal food resources are presumed to have a lesser prehistoric importance, though the archaeological record actually supports the importance of resources other than salmon as having pervasive affects on cultural patterning in the Columbia Plateau. Data show that it was not until recent times that salmon occurrence had the effect on cultural systems that has been observed in historic times. Close

• 36. [Article] 1979 status report for ocean salmon fisheries off Oregon.

  This report summarizes the 1979 ocean salmon fishing season off the Oregon coast. Troll fishery landings were obtained directly from commercial fish receiving tickets supplemented with a survey of fish ...

  Citation × Citation Citation Abstract Copy Title: 1979 status report for ocean salmon fisheries off Oregon. Author: Oregon Dept. of Fish and Wildlife. Ocean Salmon Management. This report summarizes the 1979 ocean salmon fishing season off the Oregon coast. Troll fishery landings were obtained directly from commercial fish receiving tickets supplemented with a survey of fish buyers to obtain the most up-to-date estimate of total landings. Recreational catch and effort were obtained from creel census survey at coastal ports by ODFW personnel. Recreational catch and effort information is included for the period May 12 through September 16 while commercial troll landings encompass the period from May 1 through November 13. Title: 1979 status report for ocean salmon fisheries off Oregon. Author: Oregon Dept. of Fish and Wildlife. Ocean Salmon Management. This report summarizes the 1979 ocean salmon fishing season off the Oregon coast. Troll fishery landings were obtained directly from commercial fish receiving tickets supplemented with a survey of fish buyers to obtain the most up-to-date estimate of total landings. Recreational catch and effort were obtained from creel census survey at coastal ports by ODFW personnel. Recreational catch and effort information is included for the period May 12 through September 16 while commercial troll landings encompass the period from May 1 through November 13. Close

• 37. [Article] Oregon coastal salmon and steelhead tagging programs

  Part I. To aid in the management of the Tillamook Bay commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1953. General migration behavior, the minimum ...

  Citation × Citation Citation Abstract Copy Title: Oregon coastal salmon and steelhead tagging programs Author: Henry, Kenneth A., Morgan, Alfred R. Part I. To aid in the management of the Tillamook Bay commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1953. General migration behavior, the minimum length of time the fish remained in the fishery, population sizes, and fishing mortalities were determined from this study. Part II. To aid in the management of the Siletz River commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1954. General migration behavior, the minimum length of time fish remained in the fishery, population estimates, and fishing mortalities were determined. Title: Oregon coastal salmon and steelhead tagging programs Author: Henry, Kenneth A., Morgan, Alfred R. Part I. To aid in the management of the Tillamook Bay commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1953. General migration behavior, the minimum length of time the fish remained in the fishery, population sizes, and fishing mortalities were determined from this study. Part II. To aid in the management of the Siletz River commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1954. General migration behavior, the minimum length of time fish remained in the fishery, population estimates, and fishing mortalities were determined. Close

• 38. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2013 Annual Progress Report

  Abstract -- This annual progress report summarizes spring Chinook Salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2013. Also summarized are the ...

  Citation × Citation Citation Abstract Copy Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2013 Annual Progress Report Abstract -- This annual progress report summarizes spring Chinook Salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2013. Also summarized are the associated broodstock monitoring data collected at weirs in the Grande Ronde Basin that are operated by our co-managers, the Nez Perce Tribe (NPT; Lostine River) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR; Catherine Creek and Upper Grande Ronde River). The main objectives of this report are to document and evaluate spring Chinook Salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins (CTUIR and NPT have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River that are discussed and evaluated in separate reports prepared by each co-management agency). Overall, these data are used to modify salmon culture practices, as needed, in order to optimize egg-to-smolt survival rate, smolt quality, and smolt-toadult survival rate, and monitor spawning in nature by hatchery-reared salmon. This report provides information on rearing and release operations for brood year (BY) 2011 of juvenile Chinook Salmon smolts, the collection of eggs for BY 2013, numbers and characteristics of mature Chinook Salmon in the 2013 return year, the 2013 spawning year at Lookingglass Fish Hatchery and in nature, bacterial kidney disease (BKD), and survival information (e.g., SAR, R:S) for BY 2008. These metrics document the success of these programs in meeting the LSRCP objectives for mature salmon returning to the mitigation area above Lower Granite Dam (LGD) and for harvest below LGD. In order to avoid confusion around whether jacks (age 3) are included with adult metrics, we will use the convention that “adults” include only ages 4 and 5 and “total” or “mature salmon” include all identifiable sexually mature salmon ages 3–5. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2013 Annual Progress Report Abstract -- This annual progress report summarizes spring Chinook Salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2013. Also summarized are the associated broodstock monitoring data collected at weirs in the Grande Ronde Basin that are operated by our co-managers, the Nez Perce Tribe (NPT; Lostine River) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR; Catherine Creek and Upper Grande Ronde River). The main objectives of this report are to document and evaluate spring Chinook Salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins (CTUIR and NPT have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River that are discussed and evaluated in separate reports prepared by each co-management agency). Overall, these data are used to modify salmon culture practices, as needed, in order to optimize egg-to-smolt survival rate, smolt quality, and smolt-toadult survival rate, and monitor spawning in nature by hatchery-reared salmon. This report provides information on rearing and release operations for brood year (BY) 2011 of juvenile Chinook Salmon smolts, the collection of eggs for BY 2013, numbers and characteristics of mature Chinook Salmon in the 2013 return year, the 2013 spawning year at Lookingglass Fish Hatchery and in nature, bacterial kidney disease (BKD), and survival information (e.g., SAR, R:S) for BY 2008. These metrics document the success of these programs in meeting the LSRCP objectives for mature salmon returning to the mitigation area above Lower Granite Dam (LGD) and for harvest below LGD. In order to avoid confusion around whether jacks (age 3) are included with adult metrics, we will use the convention that “adults” include only ages 4 and 5 and “total” or “mature salmon” include all identifiable sexually mature salmon ages 3–5. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Close

• 39. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2014 Annual Progress Report

  Abstract -- This annual progress report summarizes spring-summer Chinook Salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2014. Also summarized ...

  Citation × Citation Citation Abstract Copy Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2014 Annual Progress Report Abstract -- This annual progress report summarizes spring-summer Chinook Salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2014. Also summarized are the associated broodstock monitoring data collected at weirs in the Grande Ronde Basin that are operated by our co-managers, the Nez Perce Tribe (NPT; Lostine River) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR; Catherine Creek and Upper Grande Ronde River). The main objectives of this report are to document and evaluate spring-sumer Chinook Salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins (CTUIR and NPT have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River that are discussed and evaluated in separate reports prepared by each co-management agency). Overall, these data are used to adaptively manage salmon culture practices in order to optimize egg-to-smolt survival rate, smolt quality, smolt-toadult survival rate, the recruits-per-spawner (R:S) ratio, and to monitor spawning in nature by hatchery-reared salmon. This report provides information on rearing and release operations for brood year (BY) 2012 of juvenile Chinook Salmon smolts, the collection of eggs for BY 2014, numbers and characteristics (e.g., age composition) of mature Chinook Salmon in the 2014 return year, the 2014 spawning year at Lookingglass Fish Hatchery and in nature, bacterial kidney disease (BKD) monitoring, and survival information (e.g., SAR, R:S) for BY 2009. These metrics document the success of these programs in meeting the LSRCP objectives for mature salmon returning to the mitigation area above Lower Granite Dam (LGD) and for harvest below LGD. In order to avoid confusion around whether jacks (age 3) are included with adult metrics, we will use the convention that “adults” include only ages 4 and 5 and “total” or “mature salmon” include all sexually mature salmon ages 3–5. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2014 Annual Progress Report Abstract -- This annual progress report summarizes spring-summer Chinook Salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2014. Also summarized are the associated broodstock monitoring data collected at weirs in the Grande Ronde Basin that are operated by our co-managers, the Nez Perce Tribe (NPT; Lostine River) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR; Catherine Creek and Upper Grande Ronde River). The main objectives of this report are to document and evaluate spring-sumer Chinook Salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins (CTUIR and NPT have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River that are discussed and evaluated in separate reports prepared by each co-management agency). Overall, these data are used to adaptively manage salmon culture practices in order to optimize egg-to-smolt survival rate, smolt quality, smolt-toadult survival rate, the recruits-per-spawner (R:S) ratio, and to monitor spawning in nature by hatchery-reared salmon. This report provides information on rearing and release operations for brood year (BY) 2012 of juvenile Chinook Salmon smolts, the collection of eggs for BY 2014, numbers and characteristics (e.g., age composition) of mature Chinook Salmon in the 2014 return year, the 2014 spawning year at Lookingglass Fish Hatchery and in nature, bacterial kidney disease (BKD) monitoring, and survival information (e.g., SAR, R:S) for BY 2009. These metrics document the success of these programs in meeting the LSRCP objectives for mature salmon returning to the mitigation area above Lower Granite Dam (LGD) and for harvest below LGD. In order to avoid confusion around whether jacks (age 3) are included with adult metrics, we will use the convention that “adults” include only ages 4 and 5 and “total” or “mature salmon” include all sexually mature salmon ages 3–5. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Close

• 40. [Article] The effects of single and multiple pathogen and parasite infections on juvenile chinook and coho salmon during early marine residency

  Nearly 3000 juvenile Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon captured in nearshore waters off the coasts of Washington and Oregon from 1999-2004 were tested for infection by Renibacterium ...

  Citation × Citation Citation Abstract Copy Title: The effects of single and multiple pathogen and parasite infections on juvenile chinook and coho salmon during early marine residency Author: Sandell, Todd A. Nearly 3000 juvenile Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon captured in nearshore waters off the coasts of Washington and Oregon from 1999-2004 were tested for infection by Renibacterium salmoninarum, Nanophyetus salmincola, and skin metacercariae. First, three quantitative PCR primer/probe sets were compared for detection of R. salmoninarum; amplification of the single copy abc gene was best at detecting medium-high levels of infection and was used in subsequent studies. Parasite infections were detected visually. Infection by N. salmincola was the most common single infection among all juvenile salmon (55.2%), followed by R. salmoninarum (27.5%) and skin metacercariae (16.5%). Infection by R. salmoninarum was highest in 2000, with 54.8% of all juvenile salmon infected, and was much lower in 2004 (<10%). Subyearling (but not yearling) Chinook salmon infected by N. salmincola had significantly reduced growth; skin metacercarial infection was associated with significantly reduced growth only for coho salmon. Infection by R. salmoninarum was associated with significantly reduced growth in yearling Chinook salmon and coho salmon. Multiple infections did not have significantly more severe effects on growth than single infections, although the prevalence of triple infections was very low. The prevalence of R. salmoninarum was significantly and positively correlated with increased survival for both yearling Chinook and coho salmon. To better understand the apparent paradox that higher prevalences correlate with increased survival, we examined the effects of ocean conditions using the summer Pacific Decadal Oscillation (PDO) index as an indicator of good (cold) or bad (warm) ocean condition years. The years 1999-2002 were cold ocean years, and 2003-2004 were warm ocean years. The prevalence of R. salmoninarum was significantly higher in cold years, when ocean conditions were favorable, and more salmon with severe infections were captured; there was no effect of infection on growth. In the summers of warm years, infected yearling Chinook and coho salmon had significantly reduced growth, and the prevalence and severity of R. salmoninarum infections declined. These data indicate that the infection is less detrimental in years with favorable ocean conditions, and suggest that R. salmoninarum infection may be a mechanism linking ocean indices to salmon survival. Title: The effects of single and multiple pathogen and parasite infections on juvenile chinook and coho salmon during early marine residency Author: Sandell, Todd A. Nearly 3000 juvenile Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon captured in nearshore waters off the coasts of Washington and Oregon from 1999-2004 were tested for infection by Renibacterium salmoninarum, Nanophyetus salmincola, and skin metacercariae. First, three quantitative PCR primer/probe sets were compared for detection of R. salmoninarum; amplification of the single copy abc gene was best at detecting medium-high levels of infection and was used in subsequent studies. Parasite infections were detected visually. Infection by N. salmincola was the most common single infection among all juvenile salmon (55.2%), followed by R. salmoninarum (27.5%) and skin metacercariae (16.5%). Infection by R. salmoninarum was highest in 2000, with 54.8% of all juvenile salmon infected, and was much lower in 2004 (<10%). Subyearling (but not yearling) Chinook salmon infected by N. salmincola had significantly reduced growth; skin metacercarial infection was associated with significantly reduced growth only for coho salmon. Infection by R. salmoninarum was associated with significantly reduced growth in yearling Chinook salmon and coho salmon. Multiple infections did not have significantly more severe effects on growth than single infections, although the prevalence of triple infections was very low. The prevalence of R. salmoninarum was significantly and positively correlated with increased survival for both yearling Chinook and coho salmon. To better understand the apparent paradox that higher prevalences correlate with increased survival, we examined the effects of ocean conditions using the summer Pacific Decadal Oscillation (PDO) index as an indicator of good (cold) or bad (warm) ocean condition years. The years 1999-2002 were cold ocean years, and 2003-2004 were warm ocean years. The prevalence of R. salmoninarum was significantly higher in cold years, when ocean conditions were favorable, and more salmon with severe infections were captured; there was no effect of infection on growth. In the summers of warm years, infected yearling Chinook and coho salmon had significantly reduced growth, and the prevalence and severity of R. salmoninarum infections declined. These data indicate that the infection is less detrimental in years with favorable ocean conditions, and suggest that R. salmoninarum infection may be a mechanism linking ocean indices to salmon survival. Close