Determining the physical and biological habitat variables that influence the abundance of juvenile salmonids in British Columbia streams will improve management practices. Habitat models are tools that provide insight into organisms’ habitat needs and provide a more efficient mechanism for estimating population abundance than direct measurement. Models have been developed for salmonids in other jurisdictions, but very few have included invertebrate drift (a primary food source for juvenile salmonids) as a predictive variable. This is because temporal and spatial variation of drift abundance are widely assumed to be so high that drift cannot be reliably estimated without unreasonable effort. This thesis investigates the temporal and spatial variability of invertebrate drift and the impact of its inclusion in habitat models for juvenile salmonid abundance in two chapters. The first objective of the first chapter was to evaluate the temporal variability of invertebrate drift by comparing the seasonal and day-to-day variation in drift abundance to spatial variation within and between sites. The second objective was to develop predictive models for invertebrate drift abundance. Aquatic, terrestrial and total invertebrate drift abundances varied primarily between sites and very little between days or months at the same site, indicating that a single day of sampling is sufficient to assess drift abundance for comparison among sites. The abundance of invertebrate drift was related to productivity- and flow-related habitat variables. The objectives of the second chapter were to develop predictive models for juvenile salmonid abundance in southwestern BC using physical and biological habitat variables, to determine whether habitat variables differ between the Coast and Interior regions of BC, to determine the contribution of invertebrate drift to the relative predictive ability of the models, and to determine cost:benefit ratios for the predictive models and their component variables. The final models for predicting abundance of all young-of-year salmonids combined, and rainbow trout (Oncorhynchus mykiss) and coho salmon (O. kisutch) individually, included variables related to stream structure and productivity, and the models for rainbow and coho showed regional differences. Invertebrate drift did not improve model fit.

Degradation of streams in urban-rural fringe regions occurs through complex interactions between hydrological, physical, chemical and biological mechanisms of the stream environment and surrounding landscape. Biological monitoring using macroinvertebrates may capture the complex and cumulative influences of land activity on the stream environment. The Salmon River catchment in the township of Langley, British Columbia, Canada straddles urban and rural environments in the Lower Fraser Valley. To date the Salmon River catchment has been subject to several environmental surveys. Following these earlier investigations, this study quantified relationships between the stream environment and changing land activity, across multiple scales, from 1975 to 2005, using macroinvertebrates as environmental integrators. Current and historical water, sediment, and macroinvertebrate information along with land use and land-cover evaluations were used to quantify relationships between the macroinvertebrate community and land activity in the catchment. Spatial and seasonal results for specific conductivity (a total dissolved ion indicator) and NO₃⁻-N and PO₄³ (nutrient indicators) traced groundwater and overland inputs to the stream environment. Nitrate guideline exceedances occurred at groundwater-influenced sites. Elevated sediment trace metal concentrations and Zn guideline exceedances occurred mid-reach in the catchment. Peak total macroinvertebrate and sensitive taxa abundance occurred mid-reach in the catchment in 2005, while richness and proportional sensitive abundance peaks were seen at groundwater-influenced sites. The dominance of tolerant to moderately pollution tolerant taxa occurred throughout. Despite historical water quality concerns at groundwater-influenced sites, greater shifts in community composition occurred in headwaters regions. Patterns of land use and land cover changed in sensitive areas (i.e. above aquifer and in the headwaters). A greater number of correlations between land activity and macroinvertebrate measures occurred at streams sites with 100 m buffers. The abundance of sensitive taxa positively correlated with the amount of agricultural land use, while rarefaction declined. Several Macroinvertebrate functional feeding groups correlated positively to forest cover, while sensitive taxa abundance and Zn concentrations declined. Results suggest continued water quality and sediment trace metal concerns, while macroinvertebrate results point to nutrient enrichment and greater historical variability in headwaters regions. Agricultural activity appears to have a stronger influence on aspects of the stream environment despite the presence of urban-rural land activity.

Seafood is a global commodity of growing importance. The present study examined contributions to global warming from three significant seafood product chains. Each of these systems were relatively fuel efficient compared to fuel intensities reported for other fisheries globally. As such, processing and transportation phases made relatively important contributions to the overall global warming impact of these systems. Energy inputs to processing were important, as was the emission-intensity of the energy format used. In the context of interest regarding the food miles concept as an indicator of sustainability, results revealed that rather the mode of transport, not the distance travelled, was the most important factor in determining overall greenhouse gas emissions from transportation. Results indicate that further research evaluating the complete supply chain of seafood products (not only the fishing phase) may reveal important opportunities for emission reductions.

Coastal cutthroat trout (Oncorhynchus clarkii clarkii) are the apex predator in the Capilano Reservoir. This thesis investigates cutthroat predation via bioenergetic modelling and demography, and genetic analysis of hybridization with coastal rainbow / steelhead trout (O. mykiss irideus). The bioenergetics model, based on stomach content analyses, reservoir temperature and growth rates, in conjunction with predator abundance, estimates that adult trout in the reservoir consumed 6.4% of coho (O. kisutch) smolt production in 2010. No evidence of cutthroat predation on juvenile steelhead out-migrants was detected, and a gape prey maximum of 36% of predator body length was found. Moderate hybridization rates between cutthroat and rainbow trout were detected, as well as previously unknown pure strains of adult rainbow trout in reservoir waters, indicating reservoir residualization. Cutthroat trout are currently a 'second tier' management species in the Capilano Watershed, and greater understanding and appreciation of their adfluvial-lacustrine life history will facilitate informed decision-making for trout conservation and restoration, and coho management in the reservoir and the Capilano Watershed.

No description available.

No description available.

Aquaculture is one of the fastest growing animal protein production industries and accounted for 47% of the world’s food fish consumption in 2010. Aquaculture production is expected to increase to compensate for projected shortfalls in seafood supply by capture fisheries. Current assessments and scenarios predicting the outcome of this increased production have limited scope and ability to distinguish alternative courses of action. Using the Global Aquaculture Performance Index (GAPI) as a starting point, I have developed an ecologically comprehensive and quantitative farm level assessment. I selected salmon as the candidate to compare production scenarios due to being economically important, data rich and farmed in a diversity of production systems. In applying the farm-level assessment to conventional net-pen salmon production and four alternative systems, I determined the ecological impact per unit of production to be significantly different. It is possible to produce a greater volume of fish for less ecological impact. While there are benefits and trade-offs in the alternative production systems, the results indicate that projected food fish demands can be met in a more sustainable manner. The Farm Level Aquaculture Performance Index (FLAPI) provides a quantitative, performance-based tool that accounts for all ecological impacts and the resulting assessments can be used to benchmark and guide future development of aquaculture. / Graduate / 0792

The present study is mainly a descriptive account of the food and feeding of the two Scottish powan populations from Loch Lomond and Loch Eck. Quantitative and qualitative comparisons of powan diet are made. Seasonal variations of diet are determined for the two populations and some aspects of the planktivorous feeding of adult pawan in Loch Lomond are examined. The partitioning of the ingested energy into somatic and non-somatic growth is considered. Factors affecting the feeding of the two populations are discussed.

Carotenoid utilization in rainbow trout (Oncorhynchus mykiss Walbaum) and Atlantic salmon (Salmo salar L.) has been investigated with respect to tissue distribution of carotenoids and the role of the liver on the bioavailability of the lipid soluble carotenoids, astaxanthin and canthaxanthin. Species-specific and tissue-specific accumulations were noted for astaxanthin and canthaxanthin in the rainbow trout and Atlantic salmon, possibly indicating fundamental differences in their utilization in these species. The liver and the kidney were revealed to be the major tissues involved in carotenoid metabolism in both rainbow trout and Atlantic salmon. Apparent digestibilities (-96% and -30% for rainbow trout and Atlantic salmon, respectively) and flesh carotenoid retentions (-12% and -5.4% for rainbow trout and Atlantic salmon, respectively) differed significantly between species, suggesting that rainbow trout are more efficient depositors of carotenoids within the flesh. Isolated rainbow trout liver perfusion experiments revealed small differences in the uptake of astaxanthin and canthaxanthin. Uptake of astaxanthin in both synthetically-derived and serum-derived models showed saturable uptake mechanism that occurred earlier than for canthaxanthin. These results can potentially offer an explanation for the better utilization of astaxanthin in rainbow trout, where the liver reduces the bioavailability of canthaxanthin through continued uptake. Results show a low hepatic extraction ratio (0.03-0.07), in line with published post-prandial elimination rates. Neither astaxanthin nor canthaxanthin significantly induced hepatic or renal xenobiotic-metabolizing enzymes in the rainbow trout, contrary to published reports in rats and mice. This may imply fundamental species-specific differences in the metabolic pathways for these carotenoids. Histochemical investigations revealed that both carotenoids significantly impacted liver structure, resulting in higher levels of total lipids and mucopolysaccharides. This is thought to be due to their antioxidant functions and their provitamin A activity. Carotenoid-treated fish also had higher levels of glycogen phosphorylase in liver sections, providing the first evidence in fish for the possibility of glucuronidation of their metabolites. The present investigations demonstrate the liver to be a major organ in carotenoid metabolism, and consequently affects carotenoid distribution and availability. In addition, carotenoid supplementation significantly affects liver structure and may potentially enhance its function. Furthermore, these investigations have provided new avenues of investigation into the use of isolated organ perfusions for biochemical nutrition research, and expanded the knowledge of liver physiology and biochemistry.

No description available.