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• 31. [Article] Clearance of plasma cortisol in coho salmon, Oncorhynchus kisutch, at various stages of smoltification

  The metabolic clearance rate (MCR) of plasma radioactivity after a single intracardial injection of ³H-cortisol was elevated during the Spring in yearling coho salmon, Oncorhynchus kisutch. The reasons ...

  Citation × Citation Citation Abstract Copy Title: Clearance of plasma cortisol in coho salmon, Oncorhynchus kisutch, at various stages of smoltification Author: Patino, Reynaldo The metabolic clearance rate (MCR) of plasma radioactivity after a single intracardial injection of ³H-cortisol was elevated during the Spring in yearling coho salmon, Oncorhynchus kisutch. The reasons for this increase in MCR are not clear, but graphical analysis suggested that there may be a seasonal correlation between MCR and gill Na/K-ATPase activity. The main plasma metabolite of ³H-cortisol was ³H-cortisone, and it appeared very rapidly following injection of the original radiotracer. The stress of handling as used in the injection protocol and various anesthetic treatments did not affect clearance of cortisol from plasma. Title: Clearance of plasma cortisol in coho salmon, Oncorhynchus kisutch, at various stages of smoltification Author: Patino, Reynaldo The metabolic clearance rate (MCR) of plasma radioactivity after a single intracardial injection of ³H-cortisol was elevated during the Spring in yearling coho salmon, Oncorhynchus kisutch. The reasons for this increase in MCR are not clear, but graphical analysis suggested that there may be a seasonal correlation between MCR and gill Na/K-ATPase activity. The main plasma metabolite of ³H-cortisol was ³H-cortisone, and it appeared very rapidly following injection of the original radiotracer. The stress of handling as used in the injection protocol and various anesthetic treatments did not affect clearance of cortisol from plasma. Close

• 32. [Article] Growth of juvenile Pacific oysters, Crassostrea gigas (Thunberg) and Manila clams, Tapes japonica (Deshayes) in effluent from salmon-macroalga polyculture system

  Experiments were carried out in fall and winter, 1990 and spring and summer, 1991 , to determine growth and mortality of juvenile Pacific oysters {Crassostrea gigas) in effluent from cultured coho salmon ...

  Citation × Citation Citation Abstract Copy Title: Growth of juvenile Pacific oysters, Crassostrea gigas (Thunberg) and Manila clams, Tapes japonica (Deshayes) in effluent from salmon-macroalga polyculture system Author: Diaz, Maria Elena, 1958- Experiments were carried out in fall and winter, 1990 and spring and summer, 1991 , to determine growth and mortality of juvenile Pacific oysters {Crassostrea gigas) in effluent from cultured coho salmon {Oncorhynchus kisutch) , and effluent from salmon in which the red macroalga Palmaria mollis was cultured. Ambient sea water from Yaquina Bay was used as a control. Juvenile Manila clams {Tapes japonica) were also tested in summer, to compare the growth response of clams with that of Pacific oysters. Measured growth parameters included: increase in mean individual live weight, specific growth rate (% increase of mean live weight per day) and mean individual organic (ash-free) weight. Temperature, chlorophyll a, phaeopigment, carbon and nitrogen concentrations and C/N ratio for all treatments were also recorded during spring and summer, 1991. The oysters grew significantly faster in effluent from salmon and salmon conditioned by macroalgae than in the control during the Fall Experiment (September 7- 0ctober 31, 1990). Mean water temperature was 13-16°C. Growth rates were significantly greater in oysters cultured in salmon effluent than in the control during the Winter Experiment (December 7, 1990-February 15, 1991). However, growth was very poor due to low water temperatures (7-10°C). Growth of oysters was significantly greater in the control than in effluent from salmon and salmon conditioned by macrolagae in the Spring Experiment (March 7-May 24, 1991). Mean water temperature was 12°C. In the Summer Experiments, (June 3-July 4 and July 19-August 17, 1991) growth of oysters was more rapid in treatments with macroalgae as compared to treatments without macroalgae Comparative experiments with juvenile Manila clams gave similar results. Percentage mortality for both oysters and clams ranged from 0 to 5% and was highest during winter and lowest during summer. Mean chlorophyll values ranged from 1 μg/1 in spring, 1991 to 11 μg/1 summer, 1991. Title: Growth of juvenile Pacific oysters, Crassostrea gigas (Thunberg) and Manila clams, Tapes japonica (Deshayes) in effluent from salmon-macroalga polyculture system Author: Diaz, Maria Elena, 1958- Experiments were carried out in fall and winter, 1990 and spring and summer, 1991 , to determine growth and mortality of juvenile Pacific oysters {Crassostrea gigas) in effluent from cultured coho salmon {Oncorhynchus kisutch) , and effluent from salmon in which the red macroalga Palmaria mollis was cultured. Ambient sea water from Yaquina Bay was used as a control. Juvenile Manila clams {Tapes japonica) were also tested in summer, to compare the growth response of clams with that of Pacific oysters. Measured growth parameters included: increase in mean individual live weight, specific growth rate (% increase of mean live weight per day) and mean individual organic (ash-free) weight. Temperature, chlorophyll a, phaeopigment, carbon and nitrogen concentrations and C/N ratio for all treatments were also recorded during spring and summer, 1991. The oysters grew significantly faster in effluent from salmon and salmon conditioned by macroalgae than in the control during the Fall Experiment (September 7- 0ctober 31, 1990). Mean water temperature was 13-16°C. Growth rates were significantly greater in oysters cultured in salmon effluent than in the control during the Winter Experiment (December 7, 1990-February 15, 1991). However, growth was very poor due to low water temperatures (7-10°C). Growth of oysters was significantly greater in the control than in effluent from salmon and salmon conditioned by macrolagae in the Spring Experiment (March 7-May 24, 1991). Mean water temperature was 12°C. In the Summer Experiments, (June 3-July 4 and July 19-August 17, 1991) growth of oysters was more rapid in treatments with macroalgae as compared to treatments without macroalgae Comparative experiments with juvenile Manila clams gave similar results. Percentage mortality for both oysters and clams ranged from 0 to 5% and was highest during winter and lowest during summer. Mean chlorophyll values ranged from 1 μg/1 in spring, 1991 to 11 μg/1 summer, 1991. Close

• 33. [Article] Odor detection by Coho salmon (Oncorhynchus kisutch) : a laboratory bioassay and genetic basis

  Citation × Citation Citation Abstract Copy Title: Odor detection by Coho salmon (Oncorhynchus kisutch) : a laboratory bioassay and genetic basis Author: Sandoval, William A. Title: Odor detection by Coho salmon (Oncorhynchus kisutch) : a laboratory bioassay and genetic basis Author: Sandoval, William A. Close

• 34. [Article] Phenotypic comparison of hatchery and wild coho salmon (Oncorhynchus kisutch) in Oregon, Washington, and California

  Phenotypic similarities of coho salmon (Oncorhynchus kisutch) stocks from Oregon, Washington, and California were compared using agglomerative and divisive cluster analyses. The phenotypic characters evaluated ...

  Citation × Citation Citation Abstract Copy Title: Phenotypic comparison of hatchery and wild coho salmon (Oncorhynchus kisutch) in Oregon, Washington, and California Author: Hjort, Randy Carl Phenotypic similarities of coho salmon (Oncorhynchus kisutch) stocks from Oregon, Washington, and California were compared using agglomerative and divisive cluster analyses. The phenotypic characters evaluated included the following: 1) the isozyme gene frequencies of transferrin and phosphoglucose isomerase; 2) the life history characters time of peak spawning and proportion of females in the population; and 3) the morphological characters scales in the lateral series, scales above the lateral line, anal rays, gill rakers, branchiostegal rays and vertebrae. Coho salmon stocks from similar environments were phenotypically similar. The groups of stocks found to be similar by the agglomerative cluster analysis were: 1) wild stocks from the northern Oregon coast; 2) wild stocks from the southern Oregon coast; 3) stocks from hatcheries using wild coho salmon for an egg source; 4) stocks from large stream systems; and 5) hatchery stocks from the northern Oregon coast. There were three trends involved with the clustering patterns: 1) stocks that are geographically close tend to be phenotypically similar; 2) stocks from large stream systems were more similar to each other than to stocks from smaller stream systems, independent of geographic nearness; and 3) hatchery stocks were more similar to each other than to wild stocks, even those in their respective stream systems, and wild stocks were more similar to each other than to hatchery stocks, even those in their respective stream systems. These trends may be useful to fishery managers for selecting donor stocks from hatcheries for transplanting to stream systems or other hatcheries. Individual phenotypic characters were correlated with characters of the stream systems. Two agglomerative cluster analyses of the characters of the stocks and the characters of the stream system were used to determine whether stream types corresponded to phenotype- types. The clustering patterns of phenotypic characters of the stocks were not similar to the clustering found for characteristics of the stream systems from which the stocks came. Title: Phenotypic comparison of hatchery and wild coho salmon (Oncorhynchus kisutch) in Oregon, Washington, and California Author: Hjort, Randy Carl Phenotypic similarities of coho salmon (Oncorhynchus kisutch) stocks from Oregon, Washington, and California were compared using agglomerative and divisive cluster analyses. The phenotypic characters evaluated included the following: 1) the isozyme gene frequencies of transferrin and phosphoglucose isomerase; 2) the life history characters time of peak spawning and proportion of females in the population; and 3) the morphological characters scales in the lateral series, scales above the lateral line, anal rays, gill rakers, branchiostegal rays and vertebrae. Coho salmon stocks from similar environments were phenotypically similar. The groups of stocks found to be similar by the agglomerative cluster analysis were: 1) wild stocks from the northern Oregon coast; 2) wild stocks from the southern Oregon coast; 3) stocks from hatcheries using wild coho salmon for an egg source; 4) stocks from large stream systems; and 5) hatchery stocks from the northern Oregon coast. There were three trends involved with the clustering patterns: 1) stocks that are geographically close tend to be phenotypically similar; 2) stocks from large stream systems were more similar to each other than to stocks from smaller stream systems, independent of geographic nearness; and 3) hatchery stocks were more similar to each other than to wild stocks, even those in their respective stream systems, and wild stocks were more similar to each other than to hatchery stocks, even those in their respective stream systems. These trends may be useful to fishery managers for selecting donor stocks from hatcheries for transplanting to stream systems or other hatcheries. Individual phenotypic characters were correlated with characters of the stream systems. Two agglomerative cluster analyses of the characters of the stocks and the characters of the stream system were used to determine whether stream types corresponded to phenotype- types. The clustering patterns of phenotypic characters of the stocks were not similar to the clustering found for characteristics of the stream systems from which the stocks came. Close

• 35. [Article] Social interaction between juvenile coho and fall chinook salmon in Sixes River, Oregon

  The nature of the interaction between juvenile coho salmon, Oncorhynchus kisutch (Walbaum), and fall chinook salmon, 0. tshawytscha (Walbaum), was studied in Sixes River, Oregon. Seining, snorkeling, and ...

  Citation × Citation Citation Abstract Copy Title: Social interaction between juvenile coho and fall chinook salmon in Sixes River, Oregon Author: Stein, Roy A. The nature of the interaction between juvenile coho salmon, Oncorhynchus kisutch (Walbaum), and fall chinook salmon, 0. tshawytscha (Walbaum), was studied in Sixes River, Oregon. Seining, snorkeling, and tagging were used to determine distribution and patterns of growth of these two species in the stream environment. Experiments conducted in flowing-water observation troughs that provided volitional residence were designed to examine the outcome of agonistic behavior between these two species. Both species were distributed throughout the entire river system in early spring. During this period, underwater surveys in the main river and selected tributaries indicated that both species preferred the same habitat. As temperatures increased during the late spring, coho disappeared from the main river, but continued to occupy cool tributaries. Fall chinook, on the other hand, were found primarily in the main river until early summer, when they moved to the estuary. Relatively few individuals remained in the tributaries. Experiments conducted in the troughs revealed that agonistic behavior, including nipping, chasing, lateral display, submission, and fleeing, occurred between juvenile coho and fall chinook. When the two species were together in the troughs and in cool tributary streams, coho grew faster than chinook. When isolated in troughs, both grew at similar rates. Coho tolerated fewer individuals per unit area than did chinook, and occupied positions of dominance near the source of incoming food at the upstream end of the troughs. Coho had brighter fin and body colors, greater fin development, deeper bodies, and were heavier than fall chinook of the same length. Coloration and morphology appeared to be important factors influencing the "apparent" size and presumably the social status of both species. Juvenile coho, with extensive development of fins and coloration and intense territorial behavior, are hypothesized to be adapted to small, cool tributary streams. Fall chinook, on the other hand, with conservative development of fins and coloration and related behavior patterns, appear to be adapted to conditions in the main river and estuary. Title: Social interaction between juvenile coho and fall chinook salmon in Sixes River, Oregon Author: Stein, Roy A. The nature of the interaction between juvenile coho salmon, Oncorhynchus kisutch (Walbaum), and fall chinook salmon, 0. tshawytscha (Walbaum), was studied in Sixes River, Oregon. Seining, snorkeling, and tagging were used to determine distribution and patterns of growth of these two species in the stream environment. Experiments conducted in flowing-water observation troughs that provided volitional residence were designed to examine the outcome of agonistic behavior between these two species. Both species were distributed throughout the entire river system in early spring. During this period, underwater surveys in the main river and selected tributaries indicated that both species preferred the same habitat. As temperatures increased during the late spring, coho disappeared from the main river, but continued to occupy cool tributaries. Fall chinook, on the other hand, were found primarily in the main river until early summer, when they moved to the estuary. Relatively few individuals remained in the tributaries. Experiments conducted in the troughs revealed that agonistic behavior, including nipping, chasing, lateral display, submission, and fleeing, occurred between juvenile coho and fall chinook. When the two species were together in the troughs and in cool tributary streams, coho grew faster than chinook. When isolated in troughs, both grew at similar rates. Coho tolerated fewer individuals per unit area than did chinook, and occupied positions of dominance near the source of incoming food at the upstream end of the troughs. Coho had brighter fin and body colors, greater fin development, deeper bodies, and were heavier than fall chinook of the same length. Coloration and morphology appeared to be important factors influencing the "apparent" size and presumably the social status of both species. Juvenile coho, with extensive development of fins and coloration and intense territorial behavior, are hypothesized to be adapted to small, cool tributary streams. Fall chinook, on the other hand, with conservative development of fins and coloration and related behavior patterns, appear to be adapted to conditions in the main river and estuary. Close

• 36. [Article] Density of the Waterborne Parasite Ceratomyxa shasta and Its Biological Effects on Salmon

  This is the publisher’s final pdf. The published article is copyrighted by American Society for Microbiology and can be found at: http://www.asm.org/.

  Citation × Citation Citation Abstract Copy Title: Density of the Waterborne Parasite Ceratomyxa shasta and Its Biological Effects on Salmon Author: Bartholomew, Jerri L., Holt, Richard A., Ray, R. Adam, Atkinson, Stephen D., Buckles, Gerri R., Hallett, Sascha L., Hurst, Charlene N. This is the publisher’s final pdf. The published article is copyrighted by American Society for Microbiology and can be found at: http://www.asm.org/. Title: Density of the Waterborne Parasite Ceratomyxa shasta and Its Biological Effects on Salmon Author: Bartholomew, Jerri L., Holt, Richard A., Ray, R. Adam, Atkinson, Stephen D., Buckles, Gerri R., Hallett, Sascha L., Hurst, Charlene N. This is the publisher’s final pdf. The published article is copyrighted by American Society for Microbiology and can be found at: http://www.asm.org/. Close

• 37. [Article] Oral immunization for possible control of furunculosis in fish

  This project was initiated in an attempt to control furunculosis (Aeromonas salmonicida) in a production hatchery rearing coho salmon. An oral vaccine was prepared and administered to 520,000 juvenile ...

  Citation × Citation Citation Abstract Copy Title: Oral immunization for possible control of furunculosis in fish Author: Frost, Gary Douglas This project was initiated in an attempt to control furunculosis (Aeromonas salmonicida) in a production hatchery rearing coho salmon. An oral vaccine was prepared and administered to 520,000 juvenile coho salmon (Oncorhynchus kisutch) at the Siletz River Salmon Hatchery prior to the onset of a predictable naturally occurring epizootic of furunculosis. A group of 65,000 salmon served as a nonimmunized control. The Fermacell Fermentor was used to grow the Aeromonas salmonicida cells. The cell yield was more than doubled with the addition of 175 grams of dextrose to the culture media accompanied by automatic control of the pH. The cells were subjected to ultrasonic disruption and the supernatant fluid was precipitated with alum. The resulting material was lyophilized and incorporated into the Oregon Moist Pellet diet at a concentration of 201.73 milligrams ± 3 milligrams per kilogram of pellets. Immunization with vaccine-containing food was begun on March 26, 1967 with 14 consecutive days of initial vaccination followed by eight weekly boosters. It was calculated that each fish could receive approximately 360.7 micrograms of vaccine during the immunization period. During the period of May 1 through July 12, 1967, all hatchery mortalities were collected and examined for the presence of Aeromonas salmonicida. Although the nonimmunized control group showed a higher total loss and a higher furunculosis loss than the immunized groups, the results fail to indicate any distinctive difference between these two lots. The lower mortalities observed in the immunized group may indicate that slight immunity had been induced by the vaccine. However, any low-level immunity which may have been produced was not sufficient to provide protection against infection by Aeromonas salmonicida. The number of mortalities appeared to be closely associated with the hatchery water temperature. An increase in water temperature was accompanied by a corresponding increase in losses. A decline in losses appeared to be associated with a decrease in water temperature. Of the fish examined, 146 animals showed the presence of an acid-fast organism tentatively identified as Mycobacterium fortuitum (Cruz). Agglutinating antibody titers on serum samples from the immunized and nonimmunized groups of fish failed to indicate any meaningful difference between these groups. Title: Oral immunization for possible control of furunculosis in fish Author: Frost, Gary Douglas This project was initiated in an attempt to control furunculosis (Aeromonas salmonicida) in a production hatchery rearing coho salmon. An oral vaccine was prepared and administered to 520,000 juvenile coho salmon (Oncorhynchus kisutch) at the Siletz River Salmon Hatchery prior to the onset of a predictable naturally occurring epizootic of furunculosis. A group of 65,000 salmon served as a nonimmunized control. The Fermacell Fermentor was used to grow the Aeromonas salmonicida cells. The cell yield was more than doubled with the addition of 175 grams of dextrose to the culture media accompanied by automatic control of the pH. The cells were subjected to ultrasonic disruption and the supernatant fluid was precipitated with alum. The resulting material was lyophilized and incorporated into the Oregon Moist Pellet diet at a concentration of 201.73 milligrams ± 3 milligrams per kilogram of pellets. Immunization with vaccine-containing food was begun on March 26, 1967 with 14 consecutive days of initial vaccination followed by eight weekly boosters. It was calculated that each fish could receive approximately 360.7 micrograms of vaccine during the immunization period. During the period of May 1 through July 12, 1967, all hatchery mortalities were collected and examined for the presence of Aeromonas salmonicida. Although the nonimmunized control group showed a higher total loss and a higher furunculosis loss than the immunized groups, the results fail to indicate any distinctive difference between these two lots. The lower mortalities observed in the immunized group may indicate that slight immunity had been induced by the vaccine. However, any low-level immunity which may have been produced was not sufficient to provide protection against infection by Aeromonas salmonicida. The number of mortalities appeared to be closely associated with the hatchery water temperature. An increase in water temperature was accompanied by a corresponding increase in losses. A decline in losses appeared to be associated with a decrease in water temperature. Of the fish examined, 146 animals showed the presence of an acid-fast organism tentatively identified as Mycobacterium fortuitum (Cruz). Agglutinating antibody titers on serum samples from the immunized and nonimmunized groups of fish failed to indicate any meaningful difference between these groups. Close

• 38. [Article] Some effects of dissolved oxygen concentration on feeding, growth and bioenergetics of juvenile Coho salmon

  The effects of three levels of dissolved oxygen (8, 5 and 3 mg/l) upon the feeding, growth and bioenergetics of juvenile coho salmon, Oncorhynchus kisutch (Walbaum), were determined in laboratory studies. ...

  Citation × Citation Citation Abstract Copy Title: Some effects of dissolved oxygen concentration on feeding, growth and bioenergetics of juvenile Coho salmon Author: Thatcher, T. O. The effects of three levels of dissolved oxygen (8, 5 and 3 mg/l) upon the feeding, growth and bioenergetics of juvenile coho salmon, Oncorhynchus kisutch (Walbaum), were determined in laboratory studies. Experiments with individual fish were conducted during the summer, fall and spring to measure rates of food consumption, standard metabolism, waste production, activity-specific dynamic action, and growth. House fly larvae were fed to the young salmon and the temperature was kept constant year-round at 15 C. The results indicated that differences due to the dissolved oxygen concentration were not great. Food consumption rate and the slope of growth rate curves were reduced only at 3 mg /I dissolved oxygen and only at near maximum food consumption rates which appear to be higher than juvenile coho salmon generally encounter in nature. However, normal competition for food and space in stream life (not present in these experiments) would be expected to curtail feeding in naturally occurring populations of juvenile cohos exposed to dissolved oxygen levels near 3 mg/l. Energy budgets were constructed from caloric determinations of the various uses made of the energy in the consumed food. These revealed that the reduced slope of the growth curve exhibited by 3 mg/l fish at near maximum feeding levels was due to sharp increases in energy requirements for activity-specific dynamic action. These energy budgets also offered the explanation that the greater loss of weight by the starved juvenile cohos kept at 8 mg /l dissolved oxygen (as compared to those kept at 3 and 5 mg/I) was due to their greater activity. Juvenile cohos kept at 5 mg/l dissolved oxygen in these studies grew at least as well as those at 8 mg /l. Again, however, this was considered to be an artifact of this experimental procedure. Fish reported upon here were not required to expend energy in competition for food and space as are those living in nature. Title: Some effects of dissolved oxygen concentration on feeding, growth and bioenergetics of juvenile Coho salmon Author: Thatcher, T. O. The effects of three levels of dissolved oxygen (8, 5 and 3 mg/l) upon the feeding, growth and bioenergetics of juvenile coho salmon, Oncorhynchus kisutch (Walbaum), were determined in laboratory studies. Experiments with individual fish were conducted during the summer, fall and spring to measure rates of food consumption, standard metabolism, waste production, activity-specific dynamic action, and growth. House fly larvae were fed to the young salmon and the temperature was kept constant year-round at 15 C. The results indicated that differences due to the dissolved oxygen concentration were not great. Food consumption rate and the slope of growth rate curves were reduced only at 3 mg /I dissolved oxygen and only at near maximum food consumption rates which appear to be higher than juvenile coho salmon generally encounter in nature. However, normal competition for food and space in stream life (not present in these experiments) would be expected to curtail feeding in naturally occurring populations of juvenile cohos exposed to dissolved oxygen levels near 3 mg/l. Energy budgets were constructed from caloric determinations of the various uses made of the energy in the consumed food. These revealed that the reduced slope of the growth curve exhibited by 3 mg/l fish at near maximum feeding levels was due to sharp increases in energy requirements for activity-specific dynamic action. These energy budgets also offered the explanation that the greater loss of weight by the starved juvenile cohos kept at 8 mg /l dissolved oxygen (as compared to those kept at 3 and 5 mg/I) was due to their greater activity. Juvenile cohos kept at 5 mg/l dissolved oxygen in these studies grew at least as well as those at 8 mg /l. Again, however, this was considered to be an artifact of this experimental procedure. Fish reported upon here were not required to expend energy in competition for food and space as are those living in nature. Close

• 39. [Article] Application of multiattribute utility analysis in determining coho salmon policy

  Policy decisions in fishery management are becoming increasingly complex and difficult. This is especially true for the salmon fisheries where policy outcomes affect the productivity of the salmon resource ...

  Citation × Citation Citation Abstract Copy Title: Application of multiattribute utility analysis in determining coho salmon policy Author: Walker, Kevin D. Policy decisions in fishery management are becoming increasingly complex and difficult. This is especially true for the salmon fisheries where policy outcomes affect the productivity of the salmon resource and the subsequent well-being of commercial fishermen, charter boat operators, Indian fishermen, and sport anglers. The objective of this study was to advance methodology from statistical decision analysis which would assist fishery managers in Oregon who must make particularly difficult choices with respect to allocation and production of coho salmon while recognizing uncertainties in the environment, incomplete state of knowledge, and the conflicting needs and desires of different interest groups. The method chosen given multiple objectives and uncertainty is multiattribute utility analysis. The approach consists, of two main components: (1) a computer model which simulates the life cycle of hatchery and stream spawning coho salmon given environmental variation, different hatchery juvenile release levels and harvest rates; and (2) an objective function which relates the different outcomes from alternative release levels and harvest rates to an assessment of the degree to which individual objectives are met. The approach was used to evaluate and rank the expected outcomes from twelve proposed policies under different hypothesized ocean environments. Analysis of the results suggest that (1) the most effective policy is achieved with a relatively low harvest rate and high smolt release level; (2) selection of a particular harvest rate is the most important decision variable; and (3) a large smolt release level can be maintained unless such releases adversely decreases the ocean survival of stream spawning coho. Because the coho fishery is a mixed stock fishery consisting of hatchery and wild stocks, the results suggest that too high a harvest rate will lead to depletion of wild stocks, considered important because of their potential contribution to production and diverse genetic traits and characteristics. Conversely, too low a harvest rate will lead to excessive escapement of coho and thus reduce the total catch. As is illustrated, formulating the coho decision problem in a multiattribute utility analysis framework is useful in two ways. First, by quantifying the objectives of the decision maker, consistent results from following alternative policies can be determined. These results provide a basis for comparison and serve as a guide for decision making involving uncertainty. Second, the approach is useful in isolating major objectives and conflicts, value judgments, trade-offs, and needed empirical evidence. Title: Application of multiattribute utility analysis in determining coho salmon policy Author: Walker, Kevin D. Policy decisions in fishery management are becoming increasingly complex and difficult. This is especially true for the salmon fisheries where policy outcomes affect the productivity of the salmon resource and the subsequent well-being of commercial fishermen, charter boat operators, Indian fishermen, and sport anglers. The objective of this study was to advance methodology from statistical decision analysis which would assist fishery managers in Oregon who must make particularly difficult choices with respect to allocation and production of coho salmon while recognizing uncertainties in the environment, incomplete state of knowledge, and the conflicting needs and desires of different interest groups. The method chosen given multiple objectives and uncertainty is multiattribute utility analysis. The approach consists, of two main components: (1) a computer model which simulates the life cycle of hatchery and stream spawning coho salmon given environmental variation, different hatchery juvenile release levels and harvest rates; and (2) an objective function which relates the different outcomes from alternative release levels and harvest rates to an assessment of the degree to which individual objectives are met. The approach was used to evaluate and rank the expected outcomes from twelve proposed policies under different hypothesized ocean environments. Analysis of the results suggest that (1) the most effective policy is achieved with a relatively low harvest rate and high smolt release level; (2) selection of a particular harvest rate is the most important decision variable; and (3) a large smolt release level can be maintained unless such releases adversely decreases the ocean survival of stream spawning coho. Because the coho fishery is a mixed stock fishery consisting of hatchery and wild stocks, the results suggest that too high a harvest rate will lead to depletion of wild stocks, considered important because of their potential contribution to production and diverse genetic traits and characteristics. Conversely, too low a harvest rate will lead to excessive escapement of coho and thus reduce the total catch. As is illustrated, formulating the coho decision problem in a multiattribute utility analysis framework is useful in two ways. First, by quantifying the objectives of the decision maker, consistent results from following alternative policies can be determined. These results provide a basis for comparison and serve as a guide for decision making involving uncertainty. Second, the approach is useful in isolating major objectives and conflicts, value judgments, trade-offs, and needed empirical evidence. Close

• 40. [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