The first part of this study investigated the effects of varying temperature regimes within the range of 8-22°C on the development and survival of Atlantic salmon (Salmo salar L.) eggs and alevins. The temperature tolerance of eggs was lower than that of alevins: egg mortality increased above 11°C and no eggs survived to eyeing or to hatching at 16 and 14°C, respectively; alevin mortality increased above 16°C and no alevins survived at 22°C. Optimal survivals of eggs and alevins occurred at 8-11°C and 10-14°C, respectively. Subsequent survival at later stages of development was largely determined by survival at earlier stages. Developmental abnormalities among eggs (pin-eyed eggs) and alevins (abnormal hatching and yolk-sac oedema) appeared to be temperature-dependent. Development time in days from fertilisation to eyeing, hatching and maximum alevin wet weight (MAWW) varied inversely with temperature. The sum of degree-days from fertilisation to eyeing and to MAWW was similar at all temperatures, but declined with increasing temperature from eyeing to hatching. The hatching period was similar for all temperatures except 8°C where it was significantly longer. Although alevin size at hatching was not temperature-dependent within the range of 8-12°C, alevin size at MAWW decreased progressively with increasing temperature (10-20°C) during the alevin stage. Fry size at first feeding did not affect their subsequent growth rate or survival. Advanced fry which were fed earliest grew at similar rates to those produced at lower temperatures and attained the greatest weight. Biomass gain was more dependent upon survival than upon mean fish weight. The second part of this study investigated the effects of timing of first feeding on fry growth and survival. Alevins fed prior to final yolk resorption were larger and had lower mortalities than those fed after MAWW. Although the "window" of first feeding opportunity lasted several weeks, delaying feeding beyond MAWW reduced absolute growth. A 5-week delay led to mortalities approaching 60%. However, first feeding can be delayed beyond MAWW for 1-2 weeks at 10°C without adversely affecting subsequent survival or growth rate.

Graduation date: 1951

Graduation date: 1971

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.

The object of this thesis was to investigate the role of two different harvest protocols on the post mortem physiology of Chinook salmon, and associated deteriorative processes that occur during frozen storage of the white muscle tissue. The two different harvest methods employed, termed 'rested' and 'exercised', were selected because of the contrasting levels of activity of the animal prior to, and upon, slaughter. While the latter represents conventional harvest techniques Rested and exercised harvesting protocols produced tissue in significantly different physiological states. Immediately post harvest, rested tissue maintained high metabolic energy stores of ATP and glycogen within the tissue, with low concentrations of tissue and plasma lactate. Exercised tissue exhibited near depleted concentrations of ATP and glycogen and a marked metabolic acidosis and lactate accumulation. When frozen immediately post harvest, rested white muscle tissue stored at -19℃ showed no significant changes in these metabolite concentrations over a six month period of profiling. However, during storage of rested tissue at -9℃, hydrolysis of ATP and glycogen with no coincident increase in lactate was observed. No significant changes in metabolite levels were observed within exercised tissue stored at -19 and -9℃, owing to the lack of metabolic energy stores. Transfer of tissue from frozen (-80 and -19℃) to chilled (-1 and +4℃) temperatures witnessed a rapid depletion of tissue ATP and glycogen stores, with rapid increases in tissue lactate concentrations. This metabolic activity was more significant in rested tissue owing to the larger concentrations of metabolic energy stores. This metabolic activity was identified to occur between the temperatures of -3 and -1.5℃ and occurred abruptly (i.e. ATP concentrations depleting in less than one hour) in time. During frozen storage (-19℃ and -9℃), harvest treatment had no significant effect on lipid oxidation processes. However, rested tissue showed a significant ability to retard lipid oxidation processes once removed from frozen storage and placed at chilled temperatures. Throughout six months storage at -19℃ storage, harvest treatment had a significant effect on the rate of protein denaturation as rested tissue consistently held higher concentrations of soluble protein over the storage period. No significant effect was observed between treatments in the rate of protein denaturation during one month frozen (-19℃) then chilled (+4℃) storage. In a supplementary frozen (-80℃) then chilled (-1℃) storage experiment, post mortem storage of rested, whole fish, at chilled (+5℃) temperatures prior to white muscle excision and freezing, was compared to rested and exercised tissue in which the white muscle had been excised and then frozen immediately post harvest. In this experiment rested tissue exposed to a 6 or 24 hour post mortem chilled storage period demonstrated significant retardation of lipid oxidation processes when compared to rested white muscle tissue that was excised and frozen immediately post harvest. Further comparison of the six and 24 hour post mortem stored tissue showed a significant increase in lipid oxidation products after 21 and 24 days chilled storage, respectively. Comparison of results from the six and 24 hour post mortem storage experiment were bordering on significance (p=0.083), warranting further investigation on the effect of post mortem storage of rested tissue on lipid oxidation processes.

Thesis (Ph. D.)--University of Washington, 1998. / Includes bibliographic references (leaves [97]-124).

Thesis (M.S.)--Oregon State University, 1990. / Typescript (photocopy). Includes bibliographical references (leaves 88-100). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (p. 123-146). Also available via the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Mémoire (M. Sc.)-- Université du Québec à Chicoutimi, 1985. / Bibliogr.: f. 99-102. Document électronique également accessible en format PDF. CaQCU