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• 1. [Article] Relationship Between Temperature and Ceratomyxa shasta–Induced Mortality In Klamath River Salmonids

  This is the publisher’s final pdf. The published article is copyrighted by American Society of Parasitologists and can be found at: http://amsocparasit.org/.

  Citation × Citation Citation Abstract Copy Title: Relationship Between Temperature and Ceratomyxa shasta–Induced Mortality In Klamath River Salmonids Author: Bartholomew, Jerri L., Holt, Richard A., Ray, R. Adam This is the publisher’s final pdf. The published article is copyrighted by American Society of Parasitologists and can be found at: http://amsocparasit.org/. Title: Relationship Between Temperature and Ceratomyxa shasta–Induced Mortality In Klamath River Salmonids Author: Bartholomew, Jerri L., Holt, Richard A., Ray, R. Adam This is the publisher’s final pdf. The published article is copyrighted by American Society of Parasitologists and can be found at: http://amsocparasit.org/. Close

• 2. [Article] Purine deposition in the skin of juvenile coho salmon, Oncorhynchus kisutch

  This study was undertaken to quantitatively evaluate the relationship between silvering of the skin of juvenile coho salmon, due to the deposition of the purines guanine and hypoxanthine, and adaptation ...

  Citation × Citation Citation Abstract Copy Title: Purine deposition in the skin of juvenile coho salmon, Oncorhynchus kisutch Author: Staley, Kathryn Boyer This study was undertaken to quantitatively evaluate the relationship between silvering of the skin of juvenile coho salmon, due to the deposition of the purines guanine and hypoxanthine, and adaptation to seawater. It was hypothesized that maximum purine deposition occurs at the time these fish normally enter seawater, that the retention of accumulated skin purines is dependent on seawater entry and that the quantity of purines stored in the skin is greatest in fish transferred to seawater at or near the normal migratory period. To test these hypotheses, four groups of fish were transferred to seawater at monthly intervals and sampled for skin purines from February through June. Fish held in freshwater served as controls. Skin purine concentration was determined by enzyme assays. Guanine deposition in the skin of fish held in freshwater until April reached a maximum on April 19. Guanine in all treatment fish declined sharply in mid-May. Guanine in the skin of fish transferred to seawater during the course of the experiments increased again by mid-June; no such increase occurred in fish held in freshwater beyond May 17. Hypoxanthine levels were much lower than guanine levels in all treatment groups and fluctuated only slightly from February through June. Skin guanine and hypoxanthine levels at the end of June were significantly higher in fish transferred to seawater in April and May than in freshwater controls. Coefficients of condition of fish in all treatment groups decreased from February through June, but were significantly lower in fish transferred to seawater in February and March than in freshwater controls at the end of June. Percent mortality of treatment groups transferred to seawater decreased as the time of transfer approached June. A biochemical role for purines during seaward migration and adaptation to seawater is suggested. It is concluded that the physiological changes associated with parr-smolt transformation, seaward migration and seawater entry are interdependent processes and that the deposition or re-utilization of skin purines may play a vital role in their successful completion. Title: Purine deposition in the skin of juvenile coho salmon, Oncorhynchus kisutch Author: Staley, Kathryn Boyer This study was undertaken to quantitatively evaluate the relationship between silvering of the skin of juvenile coho salmon, due to the deposition of the purines guanine and hypoxanthine, and adaptation to seawater. It was hypothesized that maximum purine deposition occurs at the time these fish normally enter seawater, that the retention of accumulated skin purines is dependent on seawater entry and that the quantity of purines stored in the skin is greatest in fish transferred to seawater at or near the normal migratory period. To test these hypotheses, four groups of fish were transferred to seawater at monthly intervals and sampled for skin purines from February through June. Fish held in freshwater served as controls. Skin purine concentration was determined by enzyme assays. Guanine deposition in the skin of fish held in freshwater until April reached a maximum on April 19. Guanine in all treatment fish declined sharply in mid-May. Guanine in the skin of fish transferred to seawater during the course of the experiments increased again by mid-June; no such increase occurred in fish held in freshwater beyond May 17. Hypoxanthine levels were much lower than guanine levels in all treatment groups and fluctuated only slightly from February through June. Skin guanine and hypoxanthine levels at the end of June were significantly higher in fish transferred to seawater in April and May than in freshwater controls. Coefficients of condition of fish in all treatment groups decreased from February through June, but were significantly lower in fish transferred to seawater in February and March than in freshwater controls at the end of June. Percent mortality of treatment groups transferred to seawater decreased as the time of transfer approached June. A biochemical role for purines during seaward migration and adaptation to seawater is suggested. It is concluded that the physiological changes associated with parr-smolt transformation, seaward migration and seawater entry are interdependent processes and that the deposition or re-utilization of skin purines may play a vital role in their successful completion. Close

• 3. [Article] Distribution and survival of coho salmon fry after emigration from natal streams

  Large numbers of coho salmon (Oncorhynehus kisutch) fry move downstream shortly after emergence from the gravel in many spawning tributaries. In three small coastal streams of Oregon about eight times ...

  Citation × Citation Citation Abstract Copy Title: Distribution and survival of coho salmon fry after emigration from natal streams Author: Lindsay, Robert Bryan Large numbers of coho salmon (Oncorhynehus kisutch) fry move downstream shortly after emergence from the gravel in many spawning tributaries. In three small coastal streams of Oregon about eight times more juveniles leave the tributaries as newly emerged fry than as smolts one year later. Because these early emigrants comprise such a large proportion of the total out-migration of juvenile coho from these streams, a study was initiated to determine their distribution and survival and to evaluate their contribution, if any, to the spawning escapements. In spring 1972, all emigrating coho fry were marked with ventral finclips as they entered fish traps located near the mouths of the three natal streams. Coho fry were later examined for ventral marks in July and September at 19 sampling stations in downstream areas. Emigrants generally dispersed downstream after being marked, although some upstream movement occurred once they entered-larger tributaries. A few moved as far as 9.7 km downstream from the fish traps. Few, if any, migrated directly to saltwater. The proportion of emigrants in samples of coho fry was highest directly below the fish traps and decreased farther downstream. Emigrant fry were not evenly distributed-in downstream areas. About 7% of the emigrants survived to September. Survival rates of emigrant fry and of fry In downstream areas that had not emigrated from the study streams (residents)were similar from July to September, being 43% and 46%, respectively. The survival of coho that remained above the traps was 78% for the same time period. The evidence suggests emigrants were as competitive as residents in downstream areas, but that environments downstream were more adverse than those farther upstream. Eight adult and jack coho salmon that had been marked as emigrating fry in spring 1969, returned to spawn in the natal streams in 1970-71 and 1971-72. They represented a known return of about 0.1% of the emigrants. Emigrant fry probably contributed to spawning escapements in downstream areas as well, but contributions to these areas could not be directly evaluated. Title: Distribution and survival of coho salmon fry after emigration from natal streams Author: Lindsay, Robert Bryan Large numbers of coho salmon (Oncorhynehus kisutch) fry move downstream shortly after emergence from the gravel in many spawning tributaries. In three small coastal streams of Oregon about eight times more juveniles leave the tributaries as newly emerged fry than as smolts one year later. Because these early emigrants comprise such a large proportion of the total out-migration of juvenile coho from these streams, a study was initiated to determine their distribution and survival and to evaluate their contribution, if any, to the spawning escapements. In spring 1972, all emigrating coho fry were marked with ventral finclips as they entered fish traps located near the mouths of the three natal streams. Coho fry were later examined for ventral marks in July and September at 19 sampling stations in downstream areas. Emigrants generally dispersed downstream after being marked, although some upstream movement occurred once they entered-larger tributaries. A few moved as far as 9.7 km downstream from the fish traps. Few, if any, migrated directly to saltwater. The proportion of emigrants in samples of coho fry was highest directly below the fish traps and decreased farther downstream. Emigrant fry were not evenly distributed-in downstream areas. About 7% of the emigrants survived to September. Survival rates of emigrant fry and of fry In downstream areas that had not emigrated from the study streams (residents)were similar from July to September, being 43% and 46%, respectively. The survival of coho that remained above the traps was 78% for the same time period. The evidence suggests emigrants were as competitive as residents in downstream areas, but that environments downstream were more adverse than those farther upstream. Eight adult and jack coho salmon that had been marked as emigrating fry in spring 1969, returned to spawn in the natal streams in 1970-71 and 1971-72. They represented a known return of about 0.1% of the emigrants. Emigrant fry probably contributed to spawning escapements in downstream areas as well, but contributions to these areas could not be directly evaluated. Close

• 4. [Article] Factors affecting the smolt yield of Coho salmon (Oncorhynchus kisutch) in three Oregon streams

  Data from the coho salmon migration were examined from three streams of the Alsea Watershed Study, conducted on tributaries to Drift Creek, Oregon, from 1959 through 1973. With the migration season defined ...

  Citation × Citation Citation Abstract Copy Title: Factors affecting the smolt yield of Coho salmon (Oncorhynchus kisutch) in three Oregon streams Author: Knight, Ned J. Data from the coho salmon migration were examined from three streams of the Alsea Watershed Study, conducted on tributaries to Drift Creek, Oregon, from 1959 through 1973. With the migration season defined as November 1 through May 31, the mean seasonal smolt count was 2022 fish in Deer Creek, 665 in Flynn Creek, and 277 in Needle Branch. A general decline in numbers in the later years of the study was countered by a significant increase in mean length. The peak migration time was in late March and early April in each stream. A general approach to correlate physical and biological factors to the total seasonal smolt count in each stream through single regression analyses was mostly unsuccessful. A hypothesized positive relationship between summer discharge and smolt yield could not be supported, either by using mean monthly or mean maximum flows. A negative relationship between winter discharge and smolt count was hypothesized, due to increased mortality from higher flows. This hypothesis was supported by significant regressions that included mean January flows and mean highest flows. Summer temperatures (mean monthly and mean maximum for 7, 15, and 30 days) showed little correlation with the smolt output. Suspended sediment concentrations were negatively correlated with the number of smolts, as expected from the close relationship between sediment and streamflow. September biomass of juveniles in Flynn Creek was significantly related to the smolt output, though the relationships were weaker in the other two streams. The number of spawning females was positively related to the resulting smolt count but the correlations were not significant. Cutthroat trout biomass showed very little correlation with the coho smolt output. Combinations of variables in multiple regression analyses proved generally more successful than the single correlations with smolt count, but interpretation of the variables that proved significant was not always clear. For Deer Creek, 63.9% of the variability in smolt yield could be explained by the regression with September biomass and mean May maximum temperatures. September biomass, January discharge, and mean sediment concentration accounted for 80.7% of the variability in Flynn Creek smolt output. Only 53.8% of the variability in Needle Branch smolt count could be adequately explained (from January discharge and timing of the mean lowest discharge for 15 days), perhaps due to changes in stream variables following logging. When total smolt weight (biomass) was used as the dependent variable instead of count, only the Flynn Creek regression was significant (R²=0.888, with September biomass, mean lowest discharge for 15 days, and spawning female count). It is evident from these analyses that the juvenile populations in each stream have different relationships with various physical and biological factors. Other studies have shown strong positive relationships between commercial catch of coho salmon off Oregon and Washington and streamflow two years previously, corresponding to the freshwater residence period of the juveniles. In this study, however, negative relationships between winter discharge and smolt output were found. It seems that this negative correlation is masked by downstream, estuary, or ocean factors that are inherent in the relationships between catch and flow. Title: Factors affecting the smolt yield of Coho salmon (Oncorhynchus kisutch) in three Oregon streams Author: Knight, Ned J. Data from the coho salmon migration were examined from three streams of the Alsea Watershed Study, conducted on tributaries to Drift Creek, Oregon, from 1959 through 1973. With the migration season defined as November 1 through May 31, the mean seasonal smolt count was 2022 fish in Deer Creek, 665 in Flynn Creek, and 277 in Needle Branch. A general decline in numbers in the later years of the study was countered by a significant increase in mean length. The peak migration time was in late March and early April in each stream. A general approach to correlate physical and biological factors to the total seasonal smolt count in each stream through single regression analyses was mostly unsuccessful. A hypothesized positive relationship between summer discharge and smolt yield could not be supported, either by using mean monthly or mean maximum flows. A negative relationship between winter discharge and smolt count was hypothesized, due to increased mortality from higher flows. This hypothesis was supported by significant regressions that included mean January flows and mean highest flows. Summer temperatures (mean monthly and mean maximum for 7, 15, and 30 days) showed little correlation with the smolt output. Suspended sediment concentrations were negatively correlated with the number of smolts, as expected from the close relationship between sediment and streamflow. September biomass of juveniles in Flynn Creek was significantly related to the smolt output, though the relationships were weaker in the other two streams. The number of spawning females was positively related to the resulting smolt count but the correlations were not significant. Cutthroat trout biomass showed very little correlation with the coho smolt output. Combinations of variables in multiple regression analyses proved generally more successful than the single correlations with smolt count, but interpretation of the variables that proved significant was not always clear. For Deer Creek, 63.9% of the variability in smolt yield could be explained by the regression with September biomass and mean May maximum temperatures. September biomass, January discharge, and mean sediment concentration accounted for 80.7% of the variability in Flynn Creek smolt output. Only 53.8% of the variability in Needle Branch smolt count could be adequately explained (from January discharge and timing of the mean lowest discharge for 15 days), perhaps due to changes in stream variables following logging. When total smolt weight (biomass) was used as the dependent variable instead of count, only the Flynn Creek regression was significant (R²=0.888, with September biomass, mean lowest discharge for 15 days, and spawning female count). It is evident from these analyses that the juvenile populations in each stream have different relationships with various physical and biological factors. Other studies have shown strong positive relationships between commercial catch of coho salmon off Oregon and Washington and streamflow two years previously, corresponding to the freshwater residence period of the juveniles. In this study, however, negative relationships between winter discharge and smolt output were found. It seems that this negative correlation is masked by downstream, estuary, or ocean factors that are inherent in the relationships between catch and flow. Close

• 5. [Article] Behavior and survival of coho salmon, Oncorhynchus kisutch (Walbaum), in Sashin Creek, southeastern Alaska

  Behavior and survival in fresh water were studied for three brood years of coho salmon in Sashin Creek, Alaska, from October 1963, until September 1966. Investigations of spawning adults were conducted ...

  Citation × Citation Citation Abstract Copy Title: Behavior and survival of coho salmon, Oncorhynchus kisutch (Walbaum), in Sashin Creek, southeastern Alaska Author: Crone, Richard Allan Behavior and survival in fresh water were studied for three brood years of coho salmon in Sashin Creek, Alaska, from October 1963, until September 1966. Investigations of spawning adults were conducted to determine numbers of spawners, distribution on the spawning grounds, effects on pink salmon, age composition, redd life, fecundities, and egg retention. Juvenile coho were studied to determine changes in population size, distribution in the stream, age composition of the population, food habits, and rates of mortality during fresh-water life. The number of coho spawners counted into Sashin Creek each year normally varied from 50 to 300. Weir counts and estimations of the number of spawners determined from observed spawning effort and redd life were not accurate methods of estimating the coho escapement into Sashin Creek. In 1965, a more accurate estimate was obtained by tagging a portion of the run and recording marked to unmarked ratios on the spawning grounds. I estimated that less than two percent of the viable pink salmon embryos were destroyed in 1965 by the spawning activities of coho salmon. Most coho spawners returned to Sashin Creek in 1965 and 1966 in their fourth year of life after having migrated to sea in their third year (designated 4₃). Smaller numbers of 3₂ and 5₄ individuals composed the remainder of the spawning population. The mean redd life of 56 females was 13 days. A small sample of coho from Sashin Creek examined for fecundity in 1966 gave a mean of 2,868 eggs per female. A weir or fyke net was fished in the spring to estimate emigration of juvenile coho. Coho smolts left Sashin Creek from April through July; peak emigration occurred in late May or early June. Coho fry left the stream in the spring and summer in widely varying numbers from year to year. I estimated from growth data, population estimates, and analysis of scale samples that most coho juveniles remained in Sashin Creek for two growing seasons before migrating to sea. Analysis of scales from juvenile coho indicated that some reabsorption of scales occurs during the winter. The possibility of reabsorption of circuli makes back-calculation of the length of younger age-groups of coho from scale measurements unreliable. Diptera were represented more often than any other order of insects in the stomachs of juvenile coho. Hemiptera were important as food items to juvenile coho in a tributary stream. The estimated survival from egg deposition to immediately prior to emergence varied between 17.5 and. 34.9 percent for the three brood years, and averaged 27. 8 percent. Early summer populations of fry were variable in size and dependent on the size of the egg deposition of the brood. Populations of fry declined rapidly during July and early August. Instantaneous mortality rates were much higher for this period than during any other time in the fresh-water life of coho salmon in Sashin Creek. Mortality dropped to a low level during the following winter period. Title: Behavior and survival of coho salmon, Oncorhynchus kisutch (Walbaum), in Sashin Creek, southeastern Alaska Author: Crone, Richard Allan Behavior and survival in fresh water were studied for three brood years of coho salmon in Sashin Creek, Alaska, from October 1963, until September 1966. Investigations of spawning adults were conducted to determine numbers of spawners, distribution on the spawning grounds, effects on pink salmon, age composition, redd life, fecundities, and egg retention. Juvenile coho were studied to determine changes in population size, distribution in the stream, age composition of the population, food habits, and rates of mortality during fresh-water life. The number of coho spawners counted into Sashin Creek each year normally varied from 50 to 300. Weir counts and estimations of the number of spawners determined from observed spawning effort and redd life were not accurate methods of estimating the coho escapement into Sashin Creek. In 1965, a more accurate estimate was obtained by tagging a portion of the run and recording marked to unmarked ratios on the spawning grounds. I estimated that less than two percent of the viable pink salmon embryos were destroyed in 1965 by the spawning activities of coho salmon. Most coho spawners returned to Sashin Creek in 1965 and 1966 in their fourth year of life after having migrated to sea in their third year (designated 4₃). Smaller numbers of 3₂ and 5₄ individuals composed the remainder of the spawning population. The mean redd life of 56 females was 13 days. A small sample of coho from Sashin Creek examined for fecundity in 1966 gave a mean of 2,868 eggs per female. A weir or fyke net was fished in the spring to estimate emigration of juvenile coho. Coho smolts left Sashin Creek from April through July; peak emigration occurred in late May or early June. Coho fry left the stream in the spring and summer in widely varying numbers from year to year. I estimated from growth data, population estimates, and analysis of scale samples that most coho juveniles remained in Sashin Creek for two growing seasons before migrating to sea. Analysis of scales from juvenile coho indicated that some reabsorption of scales occurs during the winter. The possibility of reabsorption of circuli makes back-calculation of the length of younger age-groups of coho from scale measurements unreliable. Diptera were represented more often than any other order of insects in the stomachs of juvenile coho. Hemiptera were important as food items to juvenile coho in a tributary stream. The estimated survival from egg deposition to immediately prior to emergence varied between 17.5 and. 34.9 percent for the three brood years, and averaged 27. 8 percent. Early summer populations of fry were variable in size and dependent on the size of the egg deposition of the brood. Populations of fry declined rapidly during July and early August. Instantaneous mortality rates were much higher for this period than during any other time in the fresh-water life of coho salmon in Sashin Creek. Mortality dropped to a low level during the following winter period. Close

• 6. [Article] Properties of anti- Aeromonas salmonicida antibodies from juvenile coho salmon (Oncorhynchus kisutch)

  After parenteral immunization with Aeromonas salmonicida cells, the agglutination activity in juvenile coho salmon (Oncorhynchus kisutch) serum was associated with the macroglobulin serum fraction. Antibody ...

  Citation × Citation Citation Abstract Copy Title: Properties of anti- Aeromonas salmonicida antibodies from juvenile coho salmon (Oncorhynchus kisutch) Author: Cisar, John Ormond After parenteral immunization with Aeromonas salmonicida cells, the agglutination activity in juvenile coho salmon (Oncorhynchus kisutch) serum was associated with the macroglobulin serum fraction. Antibody activity was diminished by 30 minutes exposure to 50 C but not 45 C. Reduction with 2-mercaptoethanol and alkylation markedly lowered but did not completely destroy agglutination activity. The residual activity appeared to be maintained by noncovalent forces. The minimum antibody concentration required for agglutination of A. salmonicida cells was approximately 0.04 μgm protein/ml. The extreme sensitivity of this bacterial agglutination system is an important consideration in the interpretation of coho salmon anti- A. salmonicida titers. Specific antibodies were isolated from pooled coho salmon serum by dissociation of bacterial cell wall immune complexes with 15 percent NaCI. The procedure resulted in the recovery of about 30 percent of the total anti- A. salmonicida antibody. The purified antibodies had a sedimentation coefficient of approximately 17S. They migrated with the slowest moving serum component in alkaline polyacrylamide gel electrophoresis, and were restricted to the anodic portion of the serum immunoglobulin arc in immunoelectrophoretic separations. In spite of the restriction in electrophoretic mobility, the antibodies were quite heterogeneous and a minimum of 11 electrophoretic subpopulations of light chains were observed. Electron microscopy and sodium dodecyl sulfate-acrylamide gel electrophoresis revealed that the coho salmon anti- A. salmonicida rnacroglobulin was composed of four IgM-like subunits. No evidence for a low molecular weight antibody was obtained. Title: Properties of anti- Aeromonas salmonicida antibodies from juvenile coho salmon (Oncorhynchus kisutch) Author: Cisar, John Ormond After parenteral immunization with Aeromonas salmonicida cells, the agglutination activity in juvenile coho salmon (Oncorhynchus kisutch) serum was associated with the macroglobulin serum fraction. Antibody activity was diminished by 30 minutes exposure to 50 C but not 45 C. Reduction with 2-mercaptoethanol and alkylation markedly lowered but did not completely destroy agglutination activity. The residual activity appeared to be maintained by noncovalent forces. The minimum antibody concentration required for agglutination of A. salmonicida cells was approximately 0.04 μgm protein/ml. The extreme sensitivity of this bacterial agglutination system is an important consideration in the interpretation of coho salmon anti- A. salmonicida titers. Specific antibodies were isolated from pooled coho salmon serum by dissociation of bacterial cell wall immune complexes with 15 percent NaCI. The procedure resulted in the recovery of about 30 percent of the total anti- A. salmonicida antibody. The purified antibodies had a sedimentation coefficient of approximately 17S. They migrated with the slowest moving serum component in alkaline polyacrylamide gel electrophoresis, and were restricted to the anodic portion of the serum immunoglobulin arc in immunoelectrophoretic separations. In spite of the restriction in electrophoretic mobility, the antibodies were quite heterogeneous and a minimum of 11 electrophoretic subpopulations of light chains were observed. Electron microscopy and sodium dodecyl sulfate-acrylamide gel electrophoresis revealed that the coho salmon anti- A. salmonicida rnacroglobulin was composed of four IgM-like subunits. No evidence for a low molecular weight antibody was obtained. Close

• 7. [Article] Cellular dynamics of the intestinal epithelium of coho salmon, Oncorhynchus kisutch, as influenced by temperature and x-rays

  The cellular dynamics of the intestinal epithelium in the coho salmon, Oncorhynchus kisutch, has been studied to determine the effects of temperature and whole-body X-irradiation. In vivo experiments utilizing ...

  Citation × Citation Citation Abstract Copy Title: Cellular dynamics of the intestinal epithelium of coho salmon, Oncorhynchus kisutch, as influenced by temperature and x-rays Author: Johnson, Tod Schaefer The cellular dynamics of the intestinal epithelium in the coho salmon, Oncorhynchus kisutch, has been studied to determine the effects of temperature and whole-body X-irradiation. In vivo experiments utilizing colchicine mitotic inhibiting technique and tritiated thymidine (³H-TdR) radioautography were employed in order to evaluate the kinetics of the cell population. In vitro radiotracer enzyme assays were used to measure the conversion of ¹⁴C-2-thymidine to the precursors of DNA synthesis, dTMP, dTDP and dTTP. Colchicine solution at 0.04 mg/100 gm body weight was injected and fish sacrificed from 1 to 18 hours. Arrested mitotic figures occurred only in the basal region of the intestinal folds for all time periods. A series of ³H-TdR experiments were carried out using salmon thermally acclimated at 5°, 10°, or 18° C. Fish were injected intraperitoneally with ³H-TdR solution (1.5 μ C[subscript i]/gm body weight), then sacrificed sequentially from 10 minutes to 37 days after injection. Samples of the intestine were processed either for radioautography or for liquid scintillation studies. Radioautographs indicated initial ³H-TdR cell labeling occurred in the basal region of the intestinal folds, with subsequent cell migration up the folds, and sloughing of cells into the lumen from the tips of the folds. Renewal times were temperature dependent, with estimates of 13-15, 23-25, and in excess of 35 days for 18°, 10° and 5°C respectively. Whole-body X-irradiation at 10° C produced considerable cell damage by 21-22 days after exposure at 1,000 R level. The gastro-intestinal syndrome was manifested by 24 to 26 days after exposures of 4,000 and 8,000 R. ³H-TdR incorporation into the intestinal nucleoprotein fraction was dose dependent through 160 minutes after injection. A series of invitro radiotracer enzyme assay experiments were carried out using ¹⁴C-2-thymidine and the intestinal post-microsomal fraction (> 104,000 x G for 1 hr) from thermally acclimated coho salmon. Thymidine kinase exhibited pH optimum at pH 7.9 ± 0.1 while thymidylate kinase showed maximum activity at pH 6.8 ± 0.1. Formation of dTMP, dTDP, and dTTP exhibited saturation type substrate dependency curves, while dTMP activities measured at 5°, 100, and 18° C resulted in non-competitive inhibition at the lower temperatures. Relative thymidine kinase activities estimated for the different temperature levels were 3.6, 2.5, and 2.0 for 5° -5° C vs 10° -10° C, 5° -5° C vs 18° -18° C, and 10° -10° C vs 18° -18° C, respectively. Lowry protein assays indicated there was an inverse relationship between total protein per unit volume intestinal microsomal supernatant fraction and fish acclimation temperature. Title: Cellular dynamics of the intestinal epithelium of coho salmon, Oncorhynchus kisutch, as influenced by temperature and x-rays Author: Johnson, Tod Schaefer The cellular dynamics of the intestinal epithelium in the coho salmon, Oncorhynchus kisutch, has been studied to determine the effects of temperature and whole-body X-irradiation. In vivo experiments utilizing colchicine mitotic inhibiting technique and tritiated thymidine (³H-TdR) radioautography were employed in order to evaluate the kinetics of the cell population. In vitro radiotracer enzyme assays were used to measure the conversion of ¹⁴C-2-thymidine to the precursors of DNA synthesis, dTMP, dTDP and dTTP. Colchicine solution at 0.04 mg/100 gm body weight was injected and fish sacrificed from 1 to 18 hours. Arrested mitotic figures occurred only in the basal region of the intestinal folds for all time periods. A series of ³H-TdR experiments were carried out using salmon thermally acclimated at 5°, 10°, or 18° C. Fish were injected intraperitoneally with ³H-TdR solution (1.5 μ C[subscript i]/gm body weight), then sacrificed sequentially from 10 minutes to 37 days after injection. Samples of the intestine were processed either for radioautography or for liquid scintillation studies. Radioautographs indicated initial ³H-TdR cell labeling occurred in the basal region of the intestinal folds, with subsequent cell migration up the folds, and sloughing of cells into the lumen from the tips of the folds. Renewal times were temperature dependent, with estimates of 13-15, 23-25, and in excess of 35 days for 18°, 10° and 5°C respectively. Whole-body X-irradiation at 10° C produced considerable cell damage by 21-22 days after exposure at 1,000 R level. The gastro-intestinal syndrome was manifested by 24 to 26 days after exposures of 4,000 and 8,000 R. ³H-TdR incorporation into the intestinal nucleoprotein fraction was dose dependent through 160 minutes after injection. A series of invitro radiotracer enzyme assay experiments were carried out using ¹⁴C-2-thymidine and the intestinal post-microsomal fraction (> 104,000 x G for 1 hr) from thermally acclimated coho salmon. Thymidine kinase exhibited pH optimum at pH 7.9 ± 0.1 while thymidylate kinase showed maximum activity at pH 6.8 ± 0.1. Formation of dTMP, dTDP, and dTTP exhibited saturation type substrate dependency curves, while dTMP activities measured at 5°, 100, and 18° C resulted in non-competitive inhibition at the lower temperatures. Relative thymidine kinase activities estimated for the different temperature levels were 3.6, 2.5, and 2.0 for 5° -5° C vs 10° -10° C, 5° -5° C vs 18° -18° C, and 10° -10° C vs 18° -18° C, respectively. Lowry protein assays indicated there was an inverse relationship between total protein per unit volume intestinal microsomal supernatant fraction and fish acclimation temperature. Close

• 8. [Article] Effects of elevated temperature on juvenile Coho salmon and benthic invertebrates in model stream communities

  Juvenile coho salmon (Oncorhynchus kisutch (Walbaum)) and aquatic invertebrates were subjected to experimentally increased, but naturally fluctuating, temperatures in a model stream channel. Coho of the ...

  Citation × Citation Citation Abstract Copy Title: Effects of elevated temperature on juvenile Coho salmon and benthic invertebrates in model stream communities Author: Iverson, Ronald Albert Juvenile coho salmon (Oncorhynchus kisutch (Walbaum)) and aquatic invertebrates were subjected to experimentally increased, but naturally fluctuating, temperatures in a model stream channel. Coho of the 1969, 1970, and 1971 year classes were reared in the heated model stream and in an unheated control stream, both located at the Oak Creek laboratory west of Corvallis, Oregon. The average increment of experimental over control temperature was 4.3 C over the entire experimental period of 22 months. Temperatures in the control stream were generally favorable for growth of coho if food organisms were scarce, while temperatures in the heated stream were favorable for growth if food organisms were abundant. Coho of the 1969 year class were reared for one winter as yearlings, and total production of this group was approximately the same in the two streams. Coho of the 1970 year class were reared from small fry to smolts over a one-year period. In this group, total production in the control stream was approximately twice as great as in the heated stream. While population size was nearly the same in the two streams, coho in the control stream grew much more rapidly than in the heated stream. Total production of coho of the 1971 year class, which were reared from the egg stage, was approximately five times as great in the control as in the heated stream when the experiment was terminated in August 1971. The difference in production resulted from larger population size and higher growth rate in the control stream. Production of aquatic stages of insects was approximately twice as great in the control as in the heated stream over the period May 1970-May 1971. This difference between streams was especially marked in mayfly and stonefly nymphs, which were the most abundant insects in both streams, and which appeared to be the major sources of food for coho. The reduced growth rates of coho in the heated as compared to the control stream probably resulted from effects of temperature on the invertebrate food supply as well as from direct effects of temperature on the coho in raising their standard metabolic rates so that energy available for growth was reduced. Winter growth rates of coho in the heated stream were generally higher than in the control, probably as a result of an increase in appetite with increased temperature. Winter growth rates of the 1969 year class were high, probably because young coho fry were available as food. Winter growth rates of coho of the 1970 year class, which had a more natural food supply, were low in both streams. The insect fauna of the Oak Creek area is probably adapted to cool water temperatures, and this adaptation presumably contributed to the reduced insect production in the heated model stream. If heat tolerant species of insects were present in or able to migrate into a stream receiving a heated effluent, the simplication of the invertebrate fauna caused by the thermal pollution might increase the amount of food available to the top carnivore. Such heat-tolerant forms apparently were not present in the model streams or, if present, were not able to contribute significantly to total production. Title: Effects of elevated temperature on juvenile Coho salmon and benthic invertebrates in model stream communities Author: Iverson, Ronald Albert Juvenile coho salmon (Oncorhynchus kisutch (Walbaum)) and aquatic invertebrates were subjected to experimentally increased, but naturally fluctuating, temperatures in a model stream channel. Coho of the 1969, 1970, and 1971 year classes were reared in the heated model stream and in an unheated control stream, both located at the Oak Creek laboratory west of Corvallis, Oregon. The average increment of experimental over control temperature was 4.3 C over the entire experimental period of 22 months. Temperatures in the control stream were generally favorable for growth of coho if food organisms were scarce, while temperatures in the heated stream were favorable for growth if food organisms were abundant. Coho of the 1969 year class were reared for one winter as yearlings, and total production of this group was approximately the same in the two streams. Coho of the 1970 year class were reared from small fry to smolts over a one-year period. In this group, total production in the control stream was approximately twice as great as in the heated stream. While population size was nearly the same in the two streams, coho in the control stream grew much more rapidly than in the heated stream. Total production of coho of the 1971 year class, which were reared from the egg stage, was approximately five times as great in the control as in the heated stream when the experiment was terminated in August 1971. The difference in production resulted from larger population size and higher growth rate in the control stream. Production of aquatic stages of insects was approximately twice as great in the control as in the heated stream over the period May 1970-May 1971. This difference between streams was especially marked in mayfly and stonefly nymphs, which were the most abundant insects in both streams, and which appeared to be the major sources of food for coho. The reduced growth rates of coho in the heated as compared to the control stream probably resulted from effects of temperature on the invertebrate food supply as well as from direct effects of temperature on the coho in raising their standard metabolic rates so that energy available for growth was reduced. Winter growth rates of coho in the heated stream were generally higher than in the control, probably as a result of an increase in appetite with increased temperature. Winter growth rates of the 1969 year class were high, probably because young coho fry were available as food. Winter growth rates of coho of the 1970 year class, which had a more natural food supply, were low in both streams. The insect fauna of the Oak Creek area is probably adapted to cool water temperatures, and this adaptation presumably contributed to the reduced insect production in the heated model stream. If heat tolerant species of insects were present in or able to migrate into a stream receiving a heated effluent, the simplication of the invertebrate fauna caused by the thermal pollution might increase the amount of food available to the top carnivore. Such heat-tolerant forms apparently were not present in the model streams or, if present, were not able to contribute significantly to total production. Close

• 9. [Article] Factors affecting coho salmon production in Oregon

  Eight scale characters of known hatchery and wild coho salmon (Oncorhynchus kisutch) were compared, and a linear discriminant function was used to determine if hatchery and wild adult coho salmon could ...

  Citation × Citation Citation Abstract Copy Title: Factors affecting coho salmon production in Oregon Author: Scarnecchia, Dennis Leslie Eight scale characters of known hatchery and wild coho salmon (Oncorhynchus kisutch) were compared, and a linear discriminant function was used to determine if hatchery and wild adult coho salmon could be correctly identified by their scales. Eighty-two percent of the hatchery and 89% of the wild fish were correctly identified. Based on analysis of scales from adult salmon of unknown origin (hatchery or wild) and the estimated catch of hatchery coho (marked) taken by the Oregon sport fishery, concluded that 74.9% of the fish caught in the ocean from mid-June to mid-September 1977 had been released as smelts from hatcheries. Percentages of hatchery fish in the catch ranged from 85% near the mouth of the Columbia River to 61% at Winchester Bay on the southern Oregon coast. Fisheries on the south and central Oregon coast may have fished on higher percentages of wild coho salmon later in the season, probably because wild fish from coastal streams remained off of these ports while most fish destined for Columbia River hatcheries had already migrated northward. Scales from coho salmon were used to determine if location on the body from which they were taken would affect the values of five scale characters. Scales obtained from within a relatively small area above the lateral line between the dorsal and adipose fins differed widely in total radius, in radius of the freshwater zone, and in number of circuli in the freshwater zone. Scales taken farther above the lateral line had significantly lower values for all five characters observed. I conclude that substantial error can be introduced into interpretation of scale data if care is not taken to insure that scales from each fish come from precisely the same area of the body. A well chosen scrape sample yielded a result as satisfactory as that of a "preferred" or "key" scale. To investigate the relationship between streamflow and abundance of coho salmon, I correlated flow from several Oregon coastal rivers with catch of coho salmon from these rivers and with catch from the Oregon commercial troll fishery. I found a highly significant relationship between total streamflows during the freshwater residency of the fish for five Oregon coastal rivers combined and pounds of adult coho salmon caught by the Oregon commercial troll fishery from 1942 to 1962. There is also a significant relationship between total combined annual (January-December) flows for these rivers and a catch 2 years later. Conversely, I found a poor relationship between the lowest 60 consecutive days of summer flow and 2 two years later. I also found significant relationships between annual flows and catch in Tillamook Bay from 1934 to 1946. Only on the Siletz River from 1927 to 1940 do find a significant relationship between summer flows and catch. Higher flows during the freshwater stages of coho salmon probably provide more habitat and better conditions for growth as well as lessen susceptibility of fry and smelts to predation. I concluded that the relationships I found should probably not be used now to predict abundance of wild coho salmon because of (l) the unknown interaction between wild and hatchery fish, and (2) the preponderance of hatchery fish in the catch. Title: Factors affecting coho salmon production in Oregon Author: Scarnecchia, Dennis Leslie Eight scale characters of known hatchery and wild coho salmon (Oncorhynchus kisutch) were compared, and a linear discriminant function was used to determine if hatchery and wild adult coho salmon could be correctly identified by their scales. Eighty-two percent of the hatchery and 89% of the wild fish were correctly identified. Based on analysis of scales from adult salmon of unknown origin (hatchery or wild) and the estimated catch of hatchery coho (marked) taken by the Oregon sport fishery, concluded that 74.9% of the fish caught in the ocean from mid-June to mid-September 1977 had been released as smelts from hatcheries. Percentages of hatchery fish in the catch ranged from 85% near the mouth of the Columbia River to 61% at Winchester Bay on the southern Oregon coast. Fisheries on the south and central Oregon coast may have fished on higher percentages of wild coho salmon later in the season, probably because wild fish from coastal streams remained off of these ports while most fish destined for Columbia River hatcheries had already migrated northward. Scales from coho salmon were used to determine if location on the body from which they were taken would affect the values of five scale characters. Scales obtained from within a relatively small area above the lateral line between the dorsal and adipose fins differed widely in total radius, in radius of the freshwater zone, and in number of circuli in the freshwater zone. Scales taken farther above the lateral line had significantly lower values for all five characters observed. I conclude that substantial error can be introduced into interpretation of scale data if care is not taken to insure that scales from each fish come from precisely the same area of the body. A well chosen scrape sample yielded a result as satisfactory as that of a "preferred" or "key" scale. To investigate the relationship between streamflow and abundance of coho salmon, I correlated flow from several Oregon coastal rivers with catch of coho salmon from these rivers and with catch from the Oregon commercial troll fishery. I found a highly significant relationship between total streamflows during the freshwater residency of the fish for five Oregon coastal rivers combined and pounds of adult coho salmon caught by the Oregon commercial troll fishery from 1942 to 1962. There is also a significant relationship between total combined annual (January-December) flows for these rivers and a catch 2 years later. Conversely, I found a poor relationship between the lowest 60 consecutive days of summer flow and 2 two years later. I also found significant relationships between annual flows and catch in Tillamook Bay from 1934 to 1946. Only on the Siletz River from 1927 to 1940 do find a significant relationship between summer flows and catch. Higher flows during the freshwater stages of coho salmon probably provide more habitat and better conditions for growth as well as lessen susceptibility of fry and smelts to predation. I concluded that the relationships I found should probably not be used now to predict abundance of wild coho salmon because of (l) the unknown interaction between wild and hatchery fish, and (2) the preponderance of hatchery fish in the catch. Close

• 10. [Article] Hormonal and osmoregulatory aspects of smoltification in coho salmon, Oncorhynchus kisutch

  Coho salmon smolts (Oncorhynchus kisutch) were transported at low and high densities. (12 and 120 g/L) for short and long periods (4 and 12 h). Because smolts can be transplanted directly to seawater, ...

  Citation × Citation Citation Abstract Copy Title: Hormonal and osmoregulatory aspects of smoltification in coho salmon, Oncorhynchus kisutch Author: Specker, Jennifer Lee Coho salmon smolts (Oncorhynchus kisutch) were transported at low and high densities. (12 and 120 g/L) for short and long periods (4 and 12 h). Because smolts can be transplanted directly to seawater, half of the fish in each treatment were transported to tanks containing seawater and half to tanks containing freshwater. Plasma corticosteroids and glucose were elevated at unloading in all groups. Corticosteroids were still above the resting levels 24 h later, whereas glucose had returned to basal levels at this time. Potential smoltification indicators such as plasma thyroxin concentration and gill Na-K-ATPase activity were not affected by transportation. Increased corticosteroids were correlated to increased mortality in transported salmon compared to acclimated control fish when subjected to a bioassay of stress severe confinement. It is concluded that transportation induced stress in the fish regardless of hauling regimen, that increased corticosteroids may have potential as indicators of reduced performance capacity, that the greatest stress occurred during loading and the first few hours en route, and that transported coho salmon smolts seem to be equally fit for entry into freshwater or seawater. Hormones of the hypothalamic-pituitary system probably mediate the environmental changes and endogenous rhythms that regulate the timing and physiological alterations of smoltification. Because thyroid hyperactivity is a major endocrine component of smoltification, yearling coho salmon were injected with mammalian prolactin (PRL) and thyrotropin (TSH) to determine their effect on plasma thyroxin concentrations. The response of plasma thyroxin to TSH is similar from January through May in coho salmon, suggesting that the thyroid does not change in sensitivity to TSH. A dose of 0.04 to 0.07 I.U. TSH is the minimum dose sufficient to significantly increase plasma thyroxin concentration. PRL (1 to 9 I.U.) depressed plasma thyroxin levels in coho salmon parr, smolts, and post-smolts. Increased plasma thyroxin and gill Na-K-ATPase levels tentatively are considered indicative of smoltification, migratory readiness, and hence, seawater adaptability. In an experiment to consider a methodology which could be implemented at a culture facility to enhance the survival of ocean-going smolts and perhaps mitigate losses due to stunting, an abnormality of smoltification, coho salmon parr were maintained for 3 wk in water supplemented with sodium or calcium salts. Prolonged residence in sodium - supplemented freshwater increased plasma thyroxin levels and tended to elevate gill Na-K-ATPase activity. In contrast, acute exposure (24 h) to 75% seawater halved plasma thyroxin levels in coho salmon parr. Gradual acclimation to increased ambient salinity may accelerate changes in, or enhance, plasma thyroxin levels and gill Na-K-ATPase activity, and thus potentially improve the growth and survival of outmigrating smolts and reduce losses due to stunting. Plasma corticosteroid levels were determined during smoltification and in response to mammalian PRL and TSH. The interrenal tissue, which synthesizes corticosteroids, becomes hyperactive during smoltification. Exogenous PRL and TSH have no effect on plasma corticosteroid levels at any time during smoltification. Plasma corticosteroid levels increase eight-fold between early April and late May in coho salmon, concurrent with increasing gill Na-K-ATPase and seaward migration. Generally, plasma levels of thyroxin and corticosteroids are related inversely. Thyroxin levels are maximum in early April, with the onset of silvering, and corticosteroids are at minimal concentrations at this time. Thereafter, thyroxin levels decline and corticosteroids increase. Title: Hormonal and osmoregulatory aspects of smoltification in coho salmon, Oncorhynchus kisutch Author: Specker, Jennifer Lee Coho salmon smolts (Oncorhynchus kisutch) were transported at low and high densities. (12 and 120 g/L) for short and long periods (4 and 12 h). Because smolts can be transplanted directly to seawater, half of the fish in each treatment were transported to tanks containing seawater and half to tanks containing freshwater. Plasma corticosteroids and glucose were elevated at unloading in all groups. Corticosteroids were still above the resting levels 24 h later, whereas glucose had returned to basal levels at this time. Potential smoltification indicators such as plasma thyroxin concentration and gill Na-K-ATPase activity were not affected by transportation. Increased corticosteroids were correlated to increased mortality in transported salmon compared to acclimated control fish when subjected to a bioassay of stress severe confinement. It is concluded that transportation induced stress in the fish regardless of hauling regimen, that increased corticosteroids may have potential as indicators of reduced performance capacity, that the greatest stress occurred during loading and the first few hours en route, and that transported coho salmon smolts seem to be equally fit for entry into freshwater or seawater. Hormones of the hypothalamic-pituitary system probably mediate the environmental changes and endogenous rhythms that regulate the timing and physiological alterations of smoltification. Because thyroid hyperactivity is a major endocrine component of smoltification, yearling coho salmon were injected with mammalian prolactin (PRL) and thyrotropin (TSH) to determine their effect on plasma thyroxin concentrations. The response of plasma thyroxin to TSH is similar from January through May in coho salmon, suggesting that the thyroid does not change in sensitivity to TSH. A dose of 0.04 to 0.07 I.U. TSH is the minimum dose sufficient to significantly increase plasma thyroxin concentration. PRL (1 to 9 I.U.) depressed plasma thyroxin levels in coho salmon parr, smolts, and post-smolts. Increased plasma thyroxin and gill Na-K-ATPase levels tentatively are considered indicative of smoltification, migratory readiness, and hence, seawater adaptability. In an experiment to consider a methodology which could be implemented at a culture facility to enhance the survival of ocean-going smolts and perhaps mitigate losses due to stunting, an abnormality of smoltification, coho salmon parr were maintained for 3 wk in water supplemented with sodium or calcium salts. Prolonged residence in sodium - supplemented freshwater increased plasma thyroxin levels and tended to elevate gill Na-K-ATPase activity. In contrast, acute exposure (24 h) to 75% seawater halved plasma thyroxin levels in coho salmon parr. Gradual acclimation to increased ambient salinity may accelerate changes in, or enhance, plasma thyroxin levels and gill Na-K-ATPase activity, and thus potentially improve the growth and survival of outmigrating smolts and reduce losses due to stunting. Plasma corticosteroid levels were determined during smoltification and in response to mammalian PRL and TSH. The interrenal tissue, which synthesizes corticosteroids, becomes hyperactive during smoltification. Exogenous PRL and TSH have no effect on plasma corticosteroid levels at any time during smoltification. Plasma corticosteroid levels increase eight-fold between early April and late May in coho salmon, concurrent with increasing gill Na-K-ATPase and seaward migration. Generally, plasma levels of thyroxin and corticosteroids are related inversely. Thyroxin levels are maximum in early April, with the onset of silvering, and corticosteroids are at minimal concentrations at this time. Thereafter, thyroxin levels decline and corticosteroids increase. Close