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• 41. [Article] Marine environment-based forecasting of coho salmon (Oncorhynchus kisutch) adult recruitment

  This is the publisher’s final pdf. The published article is copyrighted by Wiley and can be found at: http://onlinelibrary.wiley.com/.

  Citation × Citation Citation Abstract Copy Title: Marine environment-based forecasting of coho salmon (Oncorhynchus kisutch) adult recruitment Author: Rupp, David E., Lawson, Peter W., Wainwright, Thomas C., Peterson, William T. This is the publisher’s final pdf. The published article is copyrighted by Wiley and can be found at: http://onlinelibrary.wiley.com/. Title: Marine environment-based forecasting of coho salmon (Oncorhynchus kisutch) adult recruitment Author: Rupp, David E., Lawson, Peter W., Wainwright, Thomas C., Peterson, William T. This is the publisher’s final pdf. The published article is copyrighted by Wiley and can be found at: http://onlinelibrary.wiley.com/. Close

• 42. [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

• 43. [Article] Infection and immune response induced by Vibrio anguillarum in juvenile coho salmon (Oncorhynchus kisutch)

  Immunity in juvenile coho salmon (Oncorhynchus kisutch) was evaluated after immunization against vibriosis by parenteral, oral or immersion methods. Relative levels of immunity were determined by protection ...

  Citation × Citation Citation Abstract Copy Title: Infection and immune response induced by Vibrio anguillarum in juvenile coho salmon (Oncorhynchus kisutch) Author: Groberg, Warren J. Immunity in juvenile coho salmon (Oncorhynchus kisutch) was evaluated after immunization against vibriosis by parenteral, oral or immersion methods. Relative levels of immunity were determined by protection of fish from experimental water-borne challenges with Vibrio anguillarum and by serum agglutination titers. Coho salmon eggs were exposed to bacterin during artificial spawning or as embryos 4-5 days before hatching. Two of the six injected embryos had agglutination titers 218 days later, and as juveniles these two fish demonstrated an anamnestic response following intraperitoneal injection of bacteria. Fish that had selected portions of their body immersed in bacteria had high levels of protection and lower agglutination titers when compared to those completely submerged in the same preparation. Results showed that parenterally immunized fish had high titers and a high level of protection, those immersed in the bacterin had lower titers but a high level of protection and those orally immunized had no serum agglutinins and only moderate protection. Previously unimmunized fish were significantly protected when passively immunized with coho salmon anti-V. anguillarum immunoglobulin partially purified by gel filtration. The agglutination titer of the partially purified antibody was 1:4. Serum or spleen cells obtained from orally immunized fish conferred no protection to fish injected with these substances. Serum from parenterally immunized fish, however, conferred a high level of protection in passively immunized fish and spleen cells from these same donors also provided moderate protection to previously nonimmune recipients. Coho salmon radiolabeled tetrameric immunoglobulin purified by ion exchange and gel filtration was effectively absorbed in the blood after it was intraperitoneally injected. The kinetics of absorption were related to water temperature with less immunoglobulin absorbed at the lower temperatures. Effects of temperature on infection were examined at seven water temperatures in 3°C increments from 3 to 21°C. The mean day to death and total mortality were related to temperature and a shorter mean day to death and higher mortality was observed at increased temperatures. The effect of temperature on the time of onset of agglutinating antibody formation in parenterally immunized fish was studied in fish held at 6, 12 and 18°C. Titers were first observed on days 10, 15 and 25 in fish held at 18, 12 and 6°C, respectively. Growth curves of V. anguillarum cultured in Brain Heart Infusion broth were determined at the same three temperatures with growth rates directly related to temperature. Title: Infection and immune response induced by Vibrio anguillarum in juvenile coho salmon (Oncorhynchus kisutch) Author: Groberg, Warren J. Immunity in juvenile coho salmon (Oncorhynchus kisutch) was evaluated after immunization against vibriosis by parenteral, oral or immersion methods. Relative levels of immunity were determined by protection of fish from experimental water-borne challenges with Vibrio anguillarum and by serum agglutination titers. Coho salmon eggs were exposed to bacterin during artificial spawning or as embryos 4-5 days before hatching. Two of the six injected embryos had agglutination titers 218 days later, and as juveniles these two fish demonstrated an anamnestic response following intraperitoneal injection of bacteria. Fish that had selected portions of their body immersed in bacteria had high levels of protection and lower agglutination titers when compared to those completely submerged in the same preparation. Results showed that parenterally immunized fish had high titers and a high level of protection, those immersed in the bacterin had lower titers but a high level of protection and those orally immunized had no serum agglutinins and only moderate protection. Previously unimmunized fish were significantly protected when passively immunized with coho salmon anti-V. anguillarum immunoglobulin partially purified by gel filtration. The agglutination titer of the partially purified antibody was 1:4. Serum or spleen cells obtained from orally immunized fish conferred no protection to fish injected with these substances. Serum from parenterally immunized fish, however, conferred a high level of protection in passively immunized fish and spleen cells from these same donors also provided moderate protection to previously nonimmune recipients. Coho salmon radiolabeled tetrameric immunoglobulin purified by ion exchange and gel filtration was effectively absorbed in the blood after it was intraperitoneally injected. The kinetics of absorption were related to water temperature with less immunoglobulin absorbed at the lower temperatures. Effects of temperature on infection were examined at seven water temperatures in 3°C increments from 3 to 21°C. The mean day to death and total mortality were related to temperature and a shorter mean day to death and higher mortality was observed at increased temperatures. The effect of temperature on the time of onset of agglutinating antibody formation in parenterally immunized fish was studied in fish held at 6, 12 and 18°C. Titers were first observed on days 10, 15 and 25 in fish held at 18, 12 and 6°C, respectively. Growth curves of V. anguillarum cultured in Brain Heart Infusion broth were determined at the same three temperatures with growth rates directly related to temperature. Close

• 44. [Article] Chemoreception in coho salmon (Oncorhynchus kisutch) : aspects of behavior, physiology, and toxicology

  Detection of L-serine and D,L-alanine by juvenile coho salmon (Oncorhynchus kisutch) was measured in a two-choice Y-trough. Threshold concentration for olfactory detection of L-serine was 10-8 M for zero-age ...

  Citation × Citation Citation Abstract Copy Title: Chemoreception in coho salmon (Oncorhynchus kisutch) : aspects of behavior, physiology, and toxicology Author: Rehnberg, Bradley Glenn Detection of L-serine and D,L-alanine by juvenile coho salmon (Oncorhynchus kisutch) was measured in a two-choice Y-trough. Threshold concentration for olfactory detection of L-serine was 10-8 M for zero-age parr, 1O-7 M for yearling parr, 10-5 M for smolts in late April-early May, and 10-6 M for smolts in June. Threshold for the detection of D,L-alanine was 10-7 M for yearling parr, 10-6 M for smolts in late April-early May, and 10-5 M for smolts in June. Zero-age fish adapted to either freshwater or seawater were able to detect L-serine at 10-9 M. In vitro olfactory receptor assays and behavioral experiments were used to examine the specificity of L-serine detection by coho salmon. Of the 10 amino acids tested, L-serine, L-alanine and L-threonine were similar in their ability to compete for the serine receptor site. All three of these amino acids as well as L-histidine elicited behavioral avoidance responses in a 2-choice Y-trough. Behavioral cross-adaptation experiments indicated that the detection of L-serine was inhibited by the adapting amino acids L-serine, L-alanine, and glycine but not by L-threonine, L-aspartic acid, or L-histidine. Classical conditioning experiments showed that serine and alanine were not discriminated from each other although either could be discriminated from L-histidine. These results, taken together, indicate that coho salmon perceive L-serine and L-alanine as identical odors. The olfactory detection of L-serine in a 2-choice Y-trough was inhibited by 2 hr exposures to mercury (Hg) or copper (Cu) but not by zinc (Zn). Upstream swimming behavior, however, was depressed by the presence of Zn as well as Hg or Cu. Of these metals, only Hg strongly inhibited the binding of L-serine to its olfactory receptor. The inability to detect L-serine in the presence of Cu did not result from Cu masking the presence of serine. Chemical speciation calculations suggest that serine-metal complexation was not extensive enough to compromise olfactory detection. Thus, the mechanism of action of Cu is unclear whereas Hg appears to act at the level of the olfactory receptor. The ability to detect and avoid L-serine was not inhibited by a continuous exposure to Zn at 100 or 500 ug/L for 21 days. Title: Chemoreception in coho salmon (Oncorhynchus kisutch) : aspects of behavior, physiology, and toxicology Author: Rehnberg, Bradley Glenn Detection of L-serine and D,L-alanine by juvenile coho salmon (Oncorhynchus kisutch) was measured in a two-choice Y-trough. Threshold concentration for olfactory detection of L-serine was 10-8 M for zero-age parr, 1O-7 M for yearling parr, 10-5 M for smolts in late April-early May, and 10-6 M for smolts in June. Threshold for the detection of D,L-alanine was 10-7 M for yearling parr, 10-6 M for smolts in late April-early May, and 10-5 M for smolts in June. Zero-age fish adapted to either freshwater or seawater were able to detect L-serine at 10-9 M. In vitro olfactory receptor assays and behavioral experiments were used to examine the specificity of L-serine detection by coho salmon. Of the 10 amino acids tested, L-serine, L-alanine and L-threonine were similar in their ability to compete for the serine receptor site. All three of these amino acids as well as L-histidine elicited behavioral avoidance responses in a 2-choice Y-trough. Behavioral cross-adaptation experiments indicated that the detection of L-serine was inhibited by the adapting amino acids L-serine, L-alanine, and glycine but not by L-threonine, L-aspartic acid, or L-histidine. Classical conditioning experiments showed that serine and alanine were not discriminated from each other although either could be discriminated from L-histidine. These results, taken together, indicate that coho salmon perceive L-serine and L-alanine as identical odors. The olfactory detection of L-serine in a 2-choice Y-trough was inhibited by 2 hr exposures to mercury (Hg) or copper (Cu) but not by zinc (Zn). Upstream swimming behavior, however, was depressed by the presence of Zn as well as Hg or Cu. Of these metals, only Hg strongly inhibited the binding of L-serine to its olfactory receptor. The inability to detect L-serine in the presence of Cu did not result from Cu masking the presence of serine. Chemical speciation calculations suggest that serine-metal complexation was not extensive enough to compromise olfactory detection. Thus, the mechanism of action of Cu is unclear whereas Hg appears to act at the level of the olfactory receptor. The ability to detect and avoid L-serine was not inhibited by a continuous exposure to Zn at 100 or 500 ug/L for 21 days. Close

• 45. [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

• 46. [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

• 47. [Article] Blood calcium and phosphorus perturbations in rainbow trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch) : some correlates of physiological stress

  Changes in blood calcium and phosphorus concentrations were characterized for rainbow trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch) following intense exercise or exposure to suspended ...

  Citation × Citation Citation Abstract Copy Title: Blood calcium and phosphorus perturbations in rainbow trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch) : some correlates of physiological stress Author: Adams, Brett Alan Changes in blood calcium and phosphorus concentrations were characterized for rainbow trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch) following intense exercise or exposure to suspended volcanic ash or topsoil. Significant elevations in blood calcium and phosphorus accompanied exercise-induced acidemia in both S. qairdneri and O. kisutch. These elevations persisted for many hours post-exercise. Previous authors have identified bone mineral as the source of the excess calcium observed during exercise-induced hypercalcemia, but data presented herein indicates that phosphorus released into the bloodstream during exercise must have an additional, non-skeletal source. Exposure of juvenile O. kisutch to suspended Mt. St. Helens volcanic ash caused significant elevations in blood calcium and phosphorus only when fish so exposed were maintained under a regime of moderate exercise. No significant changes in blood calcium or phosphorus occurred following exposure of unexercised fish to suspended volcanic ash, nor were they elicited in exercised fish exposed to an identical level of suspended topsoil. The effects of exercise-induced hypercalcemia on the blood buffering capacity of S. gairdneri were also investigated. Results obtained in vitro suggest that dissolution products of bone hydroxyapatite may significantly diminish the in vivo blood buffering power of S. gairdneri, especially during exercise-induced acidosis. Title: Blood calcium and phosphorus perturbations in rainbow trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch) : some correlates of physiological stress Author: Adams, Brett Alan Changes in blood calcium and phosphorus concentrations were characterized for rainbow trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch) following intense exercise or exposure to suspended volcanic ash or topsoil. Significant elevations in blood calcium and phosphorus accompanied exercise-induced acidemia in both S. qairdneri and O. kisutch. These elevations persisted for many hours post-exercise. Previous authors have identified bone mineral as the source of the excess calcium observed during exercise-induced hypercalcemia, but data presented herein indicates that phosphorus released into the bloodstream during exercise must have an additional, non-skeletal source. Exposure of juvenile O. kisutch to suspended Mt. St. Helens volcanic ash caused significant elevations in blood calcium and phosphorus only when fish so exposed were maintained under a regime of moderate exercise. No significant changes in blood calcium or phosphorus occurred following exposure of unexercised fish to suspended volcanic ash, nor were they elicited in exercised fish exposed to an identical level of suspended topsoil. The effects of exercise-induced hypercalcemia on the blood buffering capacity of S. gairdneri were also investigated. Results obtained in vitro suggest that dissolution products of bone hydroxyapatite may significantly diminish the in vivo blood buffering power of S. gairdneri, especially during exercise-induced acidosis. Close

• 48. [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

• 49. [Article] Reproductive rates of copepods in experimental ponds in Oregon

  Rates of birth, death and population change were calculated for Cyclops sp. and Diaptornus forbesi in Soap Creek Ponds V-VIII near Corvallis, Oregon during the interval April, 1968 to April, 1969. An egg ...

  Citation × Citation Citation Abstract Copy Title: Reproductive rates of copepods in experimental ponds in Oregon Author: Lindland, Ronald L. Rates of birth, death and population change were calculated for Cyclops sp. and Diaptornus forbesi in Soap Creek Ponds V-VIII near Corvallis, Oregon during the interval April, 1968 to April, 1969. An egg ratio method was used in calculating these rates. Duration of development of the eggs of both species was determined in the laboratory and found to be highly correlated with water temperature. Even though the ponds are adjacently located and morphometrically very similar, significant differences in birth rates and population densities between ponds were noted. Eggs were collected most frequently in pond VI for Cyclops sp. and in ponds VII and VIII for D. forbesi. Consequently, populations of each species were most stable in these respective ponds. Predation by small fishes was probably the main cause of zooplankton mortality in all four ponds. Title: Reproductive rates of copepods in experimental ponds in Oregon Author: Lindland, Ronald L. Rates of birth, death and population change were calculated for Cyclops sp. and Diaptornus forbesi in Soap Creek Ponds V-VIII near Corvallis, Oregon during the interval April, 1968 to April, 1969. An egg ratio method was used in calculating these rates. Duration of development of the eggs of both species was determined in the laboratory and found to be highly correlated with water temperature. Even though the ponds are adjacently located and morphometrically very similar, significant differences in birth rates and population densities between ponds were noted. Eggs were collected most frequently in pond VI for Cyclops sp. and in ponds VII and VIII for D. forbesi. Consequently, populations of each species were most stable in these respective ponds. Predation by small fishes was probably the main cause of zooplankton mortality in all four ponds. Close

• 50. [Article] Stress, osmoregulation, and the hormone cortisol in yearling coho salmon, Oncorhynchus kisutch

  Freshwater (FW) and seawater (SW) acclimated yearling coho salmon, Oncorhynchus kisutch, were subjected to severe confinement stress in FW, SW, or a medium (1/3 SW) that was approximately isosmotic to ...

  Citation × Citation Citation Abstract Copy Title: Stress, osmoregulation, and the hormone cortisol in yearling coho salmon, Oncorhynchus kisutch Author: Redding, Joseph Michael Freshwater (FW) and seawater (SW) acclimated yearling coho salmon, Oncorhynchus kisutch, were subjected to severe confinement stress in FW, SW, or a medium (1/3 SW) that was approximately isosmotic to the fish's blood. Chronic stress caused osmotic imbalances in FW and SW, but not in 1/3 SW. In SW, blood osmolarity and electrolyte concentrations increased, while in FW they generally decreased. Acclimation conditions (FW or SW) before stress influenced the severity and duration of the osmotic imbalance. Confinement stress greatly amplified the osmotic imbalance following transfer from FW to SW compared to that in unconfined fish whose water supply was switched from FW to SW. Plasma cortisol levels during stress were also affected by acclimation conditions and ambient salinity. Plasma cortisol levels increased during acclimation to SW. Maxmimal concentrations of approximately 220 ng/ml occurred within 1.5 h after the water source was switched from FW to SW. After 21 d in SW, cortisol levels were still slightly elevated (23 ng/ml) compared to those in FW control fish (4 ng/ml). Chronic treatment with cortisol lowered gill Na+-K+-ATPase levels in FW fish but did not affect plasma osmolarity, Na, K, Ca, or Mg levels in fish in FW or during acclimation to SW. Thyroxine (T) and triiodothyronine (T3) levels in plasma increased significantly after ambient water was switched from FW to SW. Maximal levels of T3 (8.0 ng/ml) occurred within 12 h after the initial exposure to SW, followed by a return to FW basal levels (4.0 ng/mi) within 24 h. Plasma T levels were higher than FW control levels (4.2 ng/ml) for at least 120 h after exposure to SW; peak levels (14.3 ng/ml) occurred at 12 and 72 h. Chronic treatment with cortisol significantly lowered plasma T3 levels in FW and during acclimation to SW; but it had no significant effect on T concentrations. The metabolic clearance rate of corticosteroids determined after a single injection of 3H-cortisol was higher in SW- than in FW-acclimated fish. Uptake and retention of corticosteroids in liver, gill filaments, and gall bladder bile was greater in SW than in FW fish. The stress of long-term (5 d), but not short-term (12 h), continuous confinement apparently increased the clearance rate of corticosteroids in both FW and SW fish. Chronic, but not acute, administration of exogenous cortisol at physiological levels appeared to increase the clearance rate of corticosteroids in FW fish. Title: Stress, osmoregulation, and the hormone cortisol in yearling coho salmon, Oncorhynchus kisutch Author: Redding, Joseph Michael Freshwater (FW) and seawater (SW) acclimated yearling coho salmon, Oncorhynchus kisutch, were subjected to severe confinement stress in FW, SW, or a medium (1/3 SW) that was approximately isosmotic to the fish's blood. Chronic stress caused osmotic imbalances in FW and SW, but not in 1/3 SW. In SW, blood osmolarity and electrolyte concentrations increased, while in FW they generally decreased. Acclimation conditions (FW or SW) before stress influenced the severity and duration of the osmotic imbalance. Confinement stress greatly amplified the osmotic imbalance following transfer from FW to SW compared to that in unconfined fish whose water supply was switched from FW to SW. Plasma cortisol levels during stress were also affected by acclimation conditions and ambient salinity. Plasma cortisol levels increased during acclimation to SW. Maxmimal concentrations of approximately 220 ng/ml occurred within 1.5 h after the water source was switched from FW to SW. After 21 d in SW, cortisol levels were still slightly elevated (23 ng/ml) compared to those in FW control fish (4 ng/ml). Chronic treatment with cortisol lowered gill Na+-K+-ATPase levels in FW fish but did not affect plasma osmolarity, Na, K, Ca, or Mg levels in fish in FW or during acclimation to SW. Thyroxine (T) and triiodothyronine (T3) levels in plasma increased significantly after ambient water was switched from FW to SW. Maximal levels of T3 (8.0 ng/ml) occurred within 12 h after the initial exposure to SW, followed by a return to FW basal levels (4.0 ng/mi) within 24 h. Plasma T levels were higher than FW control levels (4.2 ng/ml) for at least 120 h after exposure to SW; peak levels (14.3 ng/ml) occurred at 12 and 72 h. Chronic treatment with cortisol significantly lowered plasma T3 levels in FW and during acclimation to SW; but it had no significant effect on T concentrations. The metabolic clearance rate of corticosteroids determined after a single injection of 3H-cortisol was higher in SW- than in FW-acclimated fish. Uptake and retention of corticosteroids in liver, gill filaments, and gall bladder bile was greater in SW than in FW fish. The stress of long-term (5 d), but not short-term (12 h), continuous confinement apparently increased the clearance rate of corticosteroids in both FW and SW fish. Chronic, but not acute, administration of exogenous cortisol at physiological levels appeared to increase the clearance rate of corticosteroids in FW fish. Close