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.

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).

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 53-56).

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. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

Conventional fish monitoring requires considerable investments of equipment and labour, and often harmful and potentially fatal techniques. Emerging methods allow detection of aquatic animals by collecting water and extracting DNA that has been shed to the environment (eDNA). Present knowledge gaps in the field include minimum densities necessary for consistent detection, and persistence of eDNA after a target species has left a site. I conducted three experiments at a salmon hatchery in British Columbia to address these knowledge gaps. Water samples were taken from flow-through tanks with juvenile Coho Salmon densities ranging from 38.0g/1000L to 0.6g/1000L. To simulate field surveys in recently abandoned habitats, I sampled water from tanks after removing fish, at flow-through volumes ranging from 20,000L to 1,000,000L. Post removal sampling occurred starting at one hour and ending after just over four days of flow-through time. Water samples from tanks containing one or more fish tested positive for Coho DNA at least 70% of the time, increasing at higher densities. Samples taken after removing the fish had detection probability of 75% at flow-through volume of 40,000L. Detection failed at flow-through volumes greater than 80,000L. In stream samples, all sites with Coho or salmonid presence confirmed by conventional trapping also tested positive for target species’ eDNA. Two sites tested positive for Coho eDNA where conventional methods failed, indicating a possible higher sensitivity of eDNA sampling. I also mapped the distribution of juvenile Coho Salmon through multiple tributaries of a productive salmon system with conventional and eDNA detections. This study improves on an emerging method with a new species by addressing existing uncertainties regarding eDNA detection threshold, and signal persistence through dilution in a simulated stream pool habitat. It also demonstrates that eDNA methods can be used to assess coastal streams for presence of juvenile and resident salmonid fishes. / Graduate

Heritabilties and genetic correlations using Individual Animal Model, (IAM), analysis for weight, length and survivability were determined in both freshwater and saltwater rearing of s0 and si1 coho, (Oncorhynchus kisutch). The most important trait to salmon farmers is the saltwater market weight which was found to have heritability estimates of 0.21 and 0.45 for the s1 and s0 smolts. Estimates of heritability for survival were high, (0.29 and 0.21) for both s0 and s1 rearing strategies. Genetic correlations between freshwater and saltwater size were small, (0.33 to 0.59) indicating selection for market weight should be done during the saltwater market weight window. Significant differences were found for weight and length between strains during freshwater and saltwater rearing for both s0 and si1 coho. The northern strains, (Kitimat, Bella Coola and Pallant Creek) were significantly larger in weight and length thanthe southern strains, (Big Qualicum and Robertson Creek). The Kitimat strain was larger in weight and length than the Bella Coola and Pallant Creek strains but lower than these two strains for percent survivability. When comparing fish from the Kitimat strain reared on both a s0 and s1 rearing strategy, it was found that the s1 fish were significantly larger than the s0 fish at the market weight window. / Land and Food Systems, Faculty of / Graduate

A deterministic simulation model is used to explore the relationship between juvenile pink, chum and coho salmon growth and size-related survival in the Fraser River estuary. Parameters most sensitive to change are identified and the results related to proposals for enhancement. These results suggest that increasing the initial size of enhancement pink and chum fry, relative to the size of wild fry, prior to seaward migration and releasing them early in the spring may increase their chances of survival. If increasing total (enhancement plus wild) fry density decreases fry growth rate, the presence of enhancement fry in the estuary could reduce the survival chances of wild fry. The decrease in wild stock survival may not be apparent from estimates of adult return for many years due to errors in measurement and to the effect on survival of environmental variability. The model can be used to suggest and evaluate enhancement proposals. Areas needing further research are also indicated. / Science, Faculty of / Zoology, Department of / Graduate

from the summer dry season to the winter wet season. Such movement that connects summer and winter habitats may be particularly important for coho salmon, O. kisutch, because availability of overwintering habitat can limit freshwater survival for this species. Here, I describe basin-scale variability in the spatial pattern of fall movement for juvenile coho salmon between mainstem and tributary streams during the fall of 2002, 2003, 2004, and 2005. Juvenile coho salmon were tagged with a passive integrated transponder (PIT) and could be detected at five stationary detection sites, two located in perennial tributaries, two in intermittent tributaries, and one in the upper mainstem of the West Fork Smith River, Oregon. For each detection site, I compare the likelihood of detection during the fall by juvenile coho salmon from tagging locations over a multi-kilometer range of distances in each direction away from the tributary confluence. I developed logistic regression models with data from each detection site to estimate: 1) the relative likelihood of immigration into a tributary as compared to emigration out of the tributary, and 2) the relative likelihood of immigration into a tributary from the mainstem downstream of the tributary confluence as compared to immigration from the mainstem upstream of the confluence. For each pair of directions at each detection site, I also compare the change in the likelihood of detection with increasing distance for each direction. Overall, at the two upper-river detection sites, juvenile coho salmon were more likely to emigrate than to immigrate. At the remaining detection sites, juvenile coho salmon were no more likely to emigrate than immigrate. Of these detection sites, fish that immigrated into the mid-river perennial stream were more likely to come from the mainstem downstream of the confluence, whereas fish that immigrated into the two lower-river intermittent tributaries were more likely to come from the mainstem upstream of the confluence. Fall movement of juvenile coho salmon between tributary and mainstem habitat can occur over relatively long distances. This case study demonstrates variation among tributaries in the overall likelihood of emigration and immigration and in the source of immigrants from the mainstem, which may be related to spatial context that combines the physical characteristics and network position of tributary streams. The demonstrated variation in fall movement that connects summer and winter habitat within a stream network is a first step in exploring how complexity in movement interacts with the spatial arrangement and quality of seasonal habitats. More research on the causes of variation in the expression of fall movement will improve our understanding of how the spatial arrangement of habitat within a stream network influences the survival of juvenile coho salmon over the whole freshwater life cycle. / Graduation date: 2013