Coho salmon (Oncorhynchus kisutch) from six hatcheries operated by the Canadian Department of Fisheries and Oceans Salmonid Enhancement Project, were reared in a common facility and then subjected to a series of standardized challenge tests. Results suggest that there are genetically based differences in the response to stressful challenges among stocks of coho salmon from southern British Columbia. The challenge tests were: saltwater (30ppt); saltwater and an increase in temperature (30ppt and 4°C); high pH (9.4 and 10.0); low pH (3.55, 3.65, 3.75 and 4.1); thermal tolerance (1°C/h); and handling (30s netting). The measured parameters were plasma sodium and chloride ion concentrations for the saline and pH challenges, time to dysfunction in the thermal tolerance challenge and plasma glucose concentration in the handling challenge. No differences among stocks were found in responses to the high pH and thermal tolerance challenges. The Chehalis River stock had the smallest plasma ion increase in salt water but showed the largest plasma ion decrease in acidic waters. In some of the low pH challenges the Tenderfoot Creek stock showed less plasma ion loss than other stocks. The stock from Eagle River had the lowest plasma glucose concentration increase during handling challenges. The combined saltwater and temperature increase challenge demonstrated the cumulative effect that stressors can have. Sampling associated with the handling challenges revealed a diurnal fluctuation in resting plasma glucose concentrations. The low pH and handling challenges showed that stock performance and the magnitude of the response observed varied with rearing conditions. Although there was some variation in the magnitude of the stock response to challenges between the two rearing conditions used, differences among stocks were consistent. When the response to all challenges were assembled into a relative challenge response profile (or performance profile), each stock was unique. / Land and Food Systems, Faculty of / Graduate

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. / Graduation date: 1982

This study was designed to provide information about the juvenile life history of coho salmon, Oncorhynchus kisutch, in the Tenmile Lakes in Oregon by 1) classifying scales of spawning fish and outgoing smolts (1+), 2) assessing the contribution of juvenile life history types to the returns of adults (3₂) and jacks (2₂), and 3) comparing growth rates and survival of different types. Scales of outmigrating smolts from one brood year, jacks from two brood years, and scales of adults from four brood years were classified into juvenile life histories and examined for several scale characters. A linear discriminant function analysis was used to show the separation of the types and to determine the most distinguishing scale characters. Length of smolts at ocean entry back-calculated from scales of jacks and adults was compared with the length of the observed group of emigrating smolts. Based on variation in numbers and spacing of circuli and the size of the freshwater scale zone, believed to represent different residence time in the tributaries and the lakes, four types of juvenile life histories were defined. Fish classified as type 1, stream-reared, are believed to have reared in the tributaries until migrating as smolts in the following year. Type 2, stream-lake-reared, fish are thought to have reared in the tributaries for almost a year but then moved down to the lakes, where rearing continued until smolt migration in spring. Type 3, stream-lake- reared, are believed to have reared for a short time in the tributaries, then moved down to the lakes sometime in their first year of life. Rearing continued in the lakes until spring of the following year. Type 4, lake-reared, are thought to have moved down to the lakes shortly after emergence from the gravel, where they reared until migrating as smolts in the following spring. Scales of smolts, jacks, and adults were sorted into these four types. Presently, coho salmon fry and yearlings appear to be moving out of tributaries in late spring and from March to beginning of May, respectively. Migration of smolts out of the lake system to the ocean occurs mostly within the month of May. Recent habitat surveys show that dramatic seasonal changes occur in use of rearing habitat by juvenile coho salmon in the Tenmile Lakes tributaries from summer to winter. In winter juveniles appear to be using more low gradient, low velocity, off-channel areas than in summer. Fish of type 4 represented 90%, 43%, and 74% of the returns of adults in 1957- 58, 1963-64, and 1971-72, respectively, and 90% of the returns of jacks in 1962-63 and 1970-71. However, no type 4 fish was represented in the returns of adults in 1985-86, whereas type 1 fish represented 89% of the returns. Type 4 appeared to have grown better in fresh water, reached a larger size at outmigration, and have a greater relative survival than fish of type 2, when compared among the observed group of smolts, returning jacks, and adults. The large proportion of the escapement returning as jacks for some of the years may indicate good growing condition for juvenile coho salmon in fresh water. According to the classification of jack scales a large proportion of fish returning as jacks were lake-reared and were found to be larger at migration to ocean than fish returning as adults. This may suggest that fish that reared well in the lakes and reached a large size at outmigration had the tendency to mature early and return as jacks. Based on the analysis of scales, lake-reared juvenile coho salmon formerly contributed well to adult returns. The former high returns of jacks and adults reflect the importance of the lake habitat for the coho salmon populations of this system. In order to enhance this stock to a higher level, management strategies should be focused on making the lake habitat available to juvenile coho salmon for at least some part of their freshwater life. / Graduation date: 1992

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. / Graduation date: 1992

I investigated juvenile coho salmon (Oncorhynchus kisutch) distribution and habitat utilization in an agricultural/urban watershed, the Salmon River, Langley, B.C. The results of my empirical work confirmed the importance of instream woody debris and undercut banks in coho distribution. I examined experimentally how juvenile coho select among patches that differ in foraging profitability and in cover availability. Ideal free distribution (IFD) models were used as the practical basis for hypotheses about habitat choice by coho salmon. My experiments were conducted in artificial stream channels and involved two different types of cover, instream and overhead, and two spatial scales. The two scales (patches within individual pools and pools within stream reaches) were used to detect the effect of different levels of sampling and information processing by the fish. Juvenile coho responded positively to food abundance both within and between pools, but they did not do it as predicted by the IFD model. Cover presence further deviated coho distribution from an IFD. Within pools, coho foraged in open patches away from cover, but preferred pools with cover when choosing between separate units. None of the alternative dispersion models that I considered, derived from the IFD, fully explained the observed dispersion patterns. Coho's ability to maximize food intake rate was not only affected by the physical complexity of their habitat, but also by intraspecific competition and interference. Subsequently, I investigated experimentally coho's response to food and different densities of woody debris in natural stream reaches. If food was abundant, coho favoured pools with sparse cover, which offers accessible refuge and leaves unobstructed foraging patches where prey and perhaps also predators are easy to detect. Pools with either high densities or total lack of woody debris attracted proportionately less fish. Earlier in the summer, fry were indifferent towards cover, but as they became older their association with instream woody debris increased. Experiments I conducted during winter indicated that water velocity and temperature affected juvenile coho downstream movement. The proportion of fish that tried to leave the experimental channels increased with water discharge and decreased with water temperature. Based on the results of my empirical and experimental work, and on information derived from comparative case studies, I evaluated the potential impact of agriculture and urbanization on coho salmon habitat. Activities associated with these types of land developments tend to: a) reduce stream channel complexity; b) eliminate off-channel fish habitat; c) increase both the magnitude and the frequency of peak flows; d) augment water sediment transport; e) alter riparian vegetation; and, f) degrade water quality. A multilayered management plan, aimed at increasing coho salmon production, was developed. The plan's management strategies were devised reflecting on the different spatial scales that watershed components have and on the connectivity processes that exist among them.

Years of habitat loss, hatchery production and water regulation in the Puntledge River have potentially compromised diversity in coho salmon. Diversity was interpreted from age and early rearing history of mature coho that returned to spawn in 2009 (n=28). Life history groups were interpreted through a visual analysis of the micro-chemistry profiles in the otoliths. There were 2 age classes and 9 life history groups detected. Group differences in Sr:Ca, Ba:Ca and Mn:Ca were significant (p<0.0001) between groups with >2 members (n=6). Cluster analysis using Sr:Ca and Ba:Ca resulted in similar groups. Sr:Ca profiles indicate different rearing habitats, coho that reared in both freshwater and the estuary, and a Jack that reared entirely in the estuary. Results support the need for further studies on the extent of diversity in Puntledge coho, and management actions that identify, restore and protect important rearing habitats.

In young coho salmon (Oncorhynchus kisutch), UVR is known to elicit exposure avoidance behavior and suppress aggressiveness. The latter observation has been attributed to the indirect effect of fish seeking shade from solar UVR under rocks consequently losing sight of prospective rivals. The present study quantified the direct impacts of UVR on agonistic (Strikes, Chases, Approaches) and feeding behaviors in juvenile coho salmon by furnishing outdoor aquaria with structural elements (i.e., inverted funnels) that provided habitat complexity without generating shade during midday experimental trials. Frequencies and durations of behaviors were compared between conditions that excluded or included natural solar UVR. Results indicated that hostile pursuits (Chases) persisted significantly longer under UVR illumination. Likewise, the frequencies of more belligerent interactions (Strikes, Chases) tended to increase under UVR, while milder territorial assertions (Approaches) and foraging (Feeding Efforts) tended to decline. However, none of the latter four outcomes tested as significant.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1972. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 222-240).

Thesis (M.S. in natural resource sciences)--Washington State University, May 2010. / Title from PDF title page (viewed on July 19, 2010). "Department of Natural Resource Sciences." Includes bibliographical references (p. 43-47).

Tesis para optar al Grado de Magíster en Ciencias de la Acuicultura / Se entregan los parámetros genéticos de heredabilidad, correlaciones genéticas, y ganancia genética estimados para peso alevín, peso smolt y peso cosecha de dos líneas, año par e impar, de salmón Coho (Oncorhynchus kisutch), a partir de seis y cuatro generaciones respectivamente, del programa de reproducción de un núcleo comercial, en Chiloé, Región de Los Lagos. Se estima el nivel de consanguinidad alcanzado para cada línea en las cinco generaciones. La metodología utilizada considera el desove de reproductores individualizados, la incubación de ovas y desarrollo inicial de alevines en unidades segregadas por cada familia generada, marcaje individual de ejemplares juveniles y crecimiento en comunidad, con muestreos periódicos de peso corporal. La metodología de evaluación para la estimación de los parámetros genéticos fue el ‘modelo animal’ y los softwares Pedigree Viewer y MTDFREML.