Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on Jan. 5, 2009). With: Expression kinetics of interferon and interferon-induced genes in Atlantic salmon (Salmo salar) following infection with infectious pancreatic necrosis virus and infectious salmon anaemia virus / A.J.A McBeath ... et al. Fish and shellfish immunology 2007: 22, 230-241. With: Identification of an interferon anatagonist protein encoded by segment 7 of infectious anaemia virus / Alastair J.A. McBeath ... et al. Virus research 2006: 115, 176-184. With: Surveillance for infectious salmon anaemia virus HPRO in marine Atlantic salmon farms across Scotland / A.J.A. McBeath, N. Bain, M. Snow. Diseases of aquatic organisms (in press). With: Presence of a full length highly polymorphic region (HPR) in the ISAV haemagglutinin-esterase does not affect the primary functions of receptor binding and esterase activity/ Alastair McBeath ... et al. Includes bibliographical references.

Thesis (M.S.) in Microbiology--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 52-59 ).

Thesis (M.S.) in Biochemistry--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 48-60).

Thesis (Ph.D.) - University of St Andrews, March 2008.

Thesis (M.S.) in Zoology--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 57-65).

No description available.

This study investigated the differences imposed by the extra set of chromosomes on the immune system of a triploid animal. Various haematological and immunological parameters in diploid and triploid sibling Atlantic salmon (Salmo salar) were compared. Haematocrits were usually the same in diploid and triploid siblings. Erythrocytes and leucocytes were larger and fewer in number in triploid siblings. However, they were not larger or fewer in number by a factor of one third. The proportions of the different leucocyte populations did not differ between diploids and triploids. This was the case for 3 families of diploids and triploids. Non-specific, humoral factors were not consistently different between diploids and triploids. From an investigation of 3 families it was found that there may be family influences on how diploids and triploids compare. A study of the kinetics of responsiveness of non-specific, humoral factors showed that triploids did differ from diploids in the speed of the immune reaction or in the rate of recovery. However, the profile of the differences between diploids and triploids varied between parameters. The rate of increasing agglutinating titres in response to treatment with a commercial vaccine did not differ between diploids and triploids. However, triploids did have a higher average titre after 24 weeks in comparison to diploids. Non-specific, cellular parameters did differ between sibling diploids and triploids. Triploid kidney macrophages had an increased phagocytic capacity but the proportion of phagocytic cells did not differ. Intracellular respiratory burst activity was not different between diploid and triploid kidney macrophages. Diploids and triploids did not respond differently to predator stress and there was no difference in susceptibility to Aeromonas salmonicida ssp. salmonicida challenge. From this study there was no evidence of consistent differences in immmunocompetence or disease susceptibility of diploid or triploid Atlantic salmon.

The aquaculture of Atlantic salmon is a fast-growing industry that has drastically increased over the last decades. Traditionally, diets for Atlantic salmon contained wild sources fishmeal and fish oil but alternatives from plants are increasingly popular substitutes. Although fish do perform well on plant rich diets in terms of growth, carnivorous fish have not evolved to cope with many anti-nutritional factors and other plant derived chemicals. In recent years the importance of intestinal microbes to the health of humans has been established by profiling the microbiota using 16S rRNA as phylogenetic marker in highthroughput sequencing studies and more recently metagenomics profiling. To date, there is sparse information on the teleost intestinal microbiota and the relationship between the microbiota and intestinal health and function. To determine baselines of “healthy” gut microbiota, the gut microbial profiles of fish from freshwater facilities and seawater facilities were analysed. Shared core microbiota were identified, suggesting that certain microbes are actively maintained by the host to fulfil minimum functionality in the gut. Salinity of the environment was identified as important determining factor for the composition of the microbiota. Furthermore, it was found that exposure to plant-based diets including faba bean protein isolates (BPI) induced enteritis in fish fed and resulted in changes of the host transcriptomics including processes related to solute transport, metabolism, tissue integrity and inflammation. The gut microbiota of the fish fed BPI was also found significantly altered and functional analysis suggest an increased genetic potential for sporulation/germination and isoflavonoid biosynthesis. Microbes identified as uniquely present and absent in the fish showing high levels of enteritis across diets could be used as future screening targets to identify onset of enteritis in fish without external signs of sickness.

Salmon catch data wee analysed from fisheries in or around the mouths of some rivers on the east coast of Scotland spanning the period from the late eighteenth century to the 1980s. It was found that the numbers and sea-age composition of salmon caught and the time of year that salmon were caught varied in the long-term in a coincident manner in different fisheries. These coincident changes in salmon catch data could not be explained by changes in the operation of fisheries and were therefore the results of changes in the population of salmon returning to the Scottish coast. The observed changes in salmon population parameters often coincided with known hydrobiological events in the North Atlantic area, but simple consistent associations between hydrobiological changes and changes in salmon populations were not found. It was concluded that salmon populations were influenced by marine factors but that relationships may be complex. Since there may be several different mechanisms which can cause changes in the sea-age and time of return of salmon, it is not to be expected that a simple causative relationship should be found. The characteristics of salmon which were caught spawning in different burns within the River North Esk system during the winters of 1989/90 and 1990/91 were analysed. It was found that those fish which spawned furthest upstream tended to have a higher sea-age and smolt-age, a smaller length and entered the river earlier in the year than would have been expected if fish entering the North Esk at different times of the year spawned randomly throughout the North Esk system. Likewise those fish which spawned further downstream tended to be large (for their sea-age), had a low sea-age and smolt-age and entered the North Esk late in the year. Although less strong evidence was obtained, a similar pattern was observed for fish which spawned at different times within the spawning season. Those fish which spawned earliest (late October/early November) tended to have entered the river earliest in the year. Analysis of environmental conditions in different burns during the spawning season of 1990/91 suggested that fish which entered the North Esk at different times of year selected particular tributaries to spawn in - the segregation observed was not the result of the chance occurrence of environmental conditions which were conducive to spawning at different times of the year in different burns. The smolt-ages of the adult fish caught in each burn were similar to that of juvenile fish in each respective burn. This suggests that adult fish were returning to the part of the river system in which they were born. Time of return to freshwater and time of spawning were concluded to be adaptations to different environments within the North Esk system. However these characteristics may not be rigorously important and the constitution of a sub-population may alter as a result of selection processes perhaps in the sea.

Phenotypic variation was previously thought to be the result of complex interactions between an individual's genotype and the environment in which it exists. It is, however, now evident that an individual's phenotype may also be shaped by the environmental variation experienced by the mother, i.e. maternal effects. Environmental maternal effects have the potential to generate rapid phenotypic change in a population and so may be particularly important for evolution at ecological time-scales. The general aim of this thesis was to examine how maternal effects may influence offspring fitness and life history traits in Atlantic salmon (Salmo salar L.1758). For this species, the early juvenile period is the most critical due to their complex life cycle. Offspring rely on maternal provisioning during the early stages of development for growth and survival. Several studies on Atlantic salmon have emphasised the benefits of developing from larger eggs, yet it is unclear how the effects of rearing environment influence early life development. The thesis therefore investigated the effects of variation in maternal provisioning and female rearing environment on the development and physiology of embryos, the behaviour of newly emerged fry and the survival of fry released into the wild. Also assessed were the phenotypic changes among juvenile salmon released into the wild compared to those retained in the hatchery. For this maternal provisioning was manipulated by varying the length of time mothers from the same genetic background were maintained in captivity (2 months, 14 months and 26 months). The results of this thesis demonstrate that both maternal provisioning and female rearing environment alter the development and behaviour of salmon fry, opercular beat rate (a proxy for metabolic rate) and yolk sac absorption, and ultimately survival in the wild. Hatchery-reared fry were found to be maladapted to the natural environment for a number of phenotypic traits which are known to impact survival and the longer fry are retained in the hatchery prior to release the more phenotypically mismatched to the natural environment they become. However, increased egg size brought about my retaining females in captivity improved survival.