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.

Climate change has a profound impact on the phenology and abundance of plankton in the NE Atlantic and North Sea. There is concern that harmful algal bloom (HAB) species may increase, accompanied by negative socio-economic impacts, including threats to human health and marine harvesting. We reviewed historical major UK outbreaks of poisoning and attempted to examine the epidemiology on a finer scale by linkage of hospital admissions, GP and pathology records. As expected the incidence of shellfish poisonings was very low but accurate identification of poisoning was generally unreliable. The current UK shellfish monitoring programme is the key indicator for monitoring trends in the risk of human exposure. Using the Continuous Plankton Recorder (CPR) survey, we mapped spatial and temporal trends of various phytoplankton, including HAB species, and zooplankton (Tintinnids and Calanus). We found fundamental shifts in the relative abundance of diatoms versus dinoflagellates, with a dramatic dinoflagellate decline in recent years. Northward shifts in abundance were found for some Tintinnid and Calanus taxa. Using criteria of statistical causality, these changes were linked to climate, in particular sea surface temperature and increasingly windy conditions in the summer, with a notable non-linear interaction between these factors. Focusing on Calanus, we showed the strength of statistical links between abundance and climate variables can wax and wane as the time series lengthens. We found tentative evidence for adaptation of Calanus to climate change, but not at a level that could reverse overall long-term patterns. Links with climate are often argued to be proxies for unobserved mechanisms that determine species abundance, such as stratification. We developed a new stratification index, covering the whole NE Atlantic from 1970 to 2009. We propose that this has wide applicability in marine climate change studies. Throughout, our work demonstrates the importance of consistent long-term ecological survey data.

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.

Rastrelliger is a mackerel genus which inhabits the Indo-Pacific Regions. This genus is characterized by long, numerous and featherlike gill rakers, and anal fin without spines. Two species, Rastrelliger braahysoma and R. kanagurta, are recognized. These are identified by the differences in the ratios of the greatest body depth and the length of intestine to fork length, and the appearance of the cephalic lateral line canal systems. Synonymies, descriptions and morphometric ranges are given. The morphometric characters of the two species exhibit some intraspecific differences due to sexual dimorphism and strong allo-metric growth, R. braahysoma exhibits intraspecific geographical variation in its dorsoventral depth, greatest body depth, and inter-orbital distance; while R. kanagurta exhibits variation only in its dorsoventral depth and head depth. Both species attain their maximum growth increments before they reach sexual maturity. The vital parameters for yield prediction are as follows: the coefficient of growth rate K=0.19, 0.23; the length-weight exponent b=2.88, 3.19; the maximum length L=22.92 cm, 23.89 cm; the natural mortality coefficient M=0.38, 0.37; and the total mortality coefficient Z=0.82, 1.20 for R, braahysoma and R. kanagurta respectively. Rastrelliger fisheries in the Java Sea have not yet reached maximum exploitation which suggests the possibility of increasing production by increasing fishing intensity. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

This study explores the barriers to care women face living with HIV in New Brunswick and Nova Scotia, and also the health and support systems they navigate to improve their wellbeing. Women living with HIV are invisible within the epidemic and often to community sector employees, especially in the Maritime Provinces where men account for the largest number of diagnoses in Canada; this is a central theme in the data. The thesis is rooted in applied medical anthropology and uses qualitative and quantitative methods to capture the changing health priorities of women living with HIV as they navigate the health care systems after diagnosis. This information was used to create maps that show the availability of services in relation to women’s needs, including affordable housing, food security, accessible transportation, and reducing HIV stigma. I examine the efficiency of HIV women’s referral network in both provinces, and the way forward for organizations to meet their long-term health needs, such as widening of outreach activities and improving gendered care. The main findings of this study reveal that the barriers to care women face are not easily overcome by AIDS service organizations. Current support initiatives are no longer relevant to their lives because they are tailored mainly to men, but women increasingly value the referral activities of organizations. Among the most important contributions of this thesis is the envisioning of a women-centered care model that meets their health needs and acknowledges their diverse reality of their experiences. / Thesis / Doctor of Philosophy (PhD)

The Georges Bank area in the northwest Atlantic Ocean plays an important role in New England's economy. Overfishing has led to a rapid decrease in cod population numbers, leading to a collapse in certain stocks. Currently, the rate of decrease in cod numbers has slowed; however, population numbers are still low. In this study, I use Growth Rate Potential (GRP) to assess the current environmental quality of Georges Bank and its suitability to support a cod population. GRP is the amount of growth predicted for a fish with known prey availability and environmental conditions. With prey availability and temperature data obtained during the fall fisheries acoustics surveys in 2000, 2001 and 2002, I developed spatially explicit GRP maps, using bioenergetic and foraging models, for Atlantic cod to determine the ability of the Georges Bank environment to support a cod population. Results show that Georges Bank is able to support growth for adult Atlantic cod. In addition to GRP analysis, I studied nucleic acid concentrations of Atlantic herring. Nucleic acids play an important role in growth and development, and have been used to assess physical condition of fish as well as and current growth rates. In this study, I determine total nucleic acid concentrations of Atlantic herring caught during three different spawning stages: pre-, post-, and non-spawning, to determine how nucleic acid concentrations and energy allocation vary seasonally. Results support the hypothesis that nucleic acid concentrations can be used as condition indicators, and are highly sensitive to the spawning stage of fish showing a significant difference between the three groups, which may affect their ability as condition indicators.

This study examines the impact of natural climate variability and long-term climate change on North Atlantic tropical cyclone (TC) tracks. Using data from HURDAT for the period 1950-2007, we categorize Atlantic TCs that form in the Main Development Region into one of three track types: Straight-Moving (SM), Recurving Landfall (RCL), and Recurving Ocean (RCO) TCs. As expected, the SM storms are associated with a westward extension and strengthening of the North Atlantic Subtropical High (NASH) whereas the RCO storms coincide with a weakening of the NASH. The presence of El Nino conditions in the tropical Pacific is found to be associated with a weakening and eastward retreat of the NASH, an increase in the percentage of RCO TCs, and a decrease in the percentage of RCL TCs. Using 6-hourly wind fields from NCEP-NCAR Reanalyses, simulated tracks are computed for each historical storm in the sample using the Beta Advection Model (BAM). Using observed genesis locations, the BAM successfully reproduces the differences in TC tracks between SM, RCO and RCL storm types. When storm genesis is uniformly distributed over the MDR we find that RCL and RCO storms still exhibit a distinct difference in tracks, suggesting that differences in the large-scale steering flow over the tropical Atlantic are primarily responsible for their track differences. However the SM TCs exhibit a more northward track under the uniform genesis experiment, indicating that the more southern and western genesis location of these storms is an important contributor in determining their tracks. The observed difference between TC tracks during El Nino and La Nina events is also reproduced by the BAM under both observed and uniformly seeded genesis experiments, suggesting that it is the changes in the large-scale steering flow over the Atlantic that is responsible the larger percentage of RCO storm tracks during El Nino events. The influence of anthropogenic warming is examined using a 7 member ensemble comparing the 2xCO2 experiment to a pre-industrial control. Increased sea level pressure over the northeast and northwest quadrants of the Atlantic does not alter the average TC track.

An eddy-permitting 2-1/2-layer Reduced Gravity Ocean (RGO) model is developed. Compared with the conventional 2-1/2-layer RGO models, the new model has improvements in subsurface thermodynamics, vertical mixing scheme and open boundary conditions. Using this new 2-1/2-layer RGO model as a dynamical tool, a systematic investigation of the role of oceanic processes in controlling tropical Atlantic sea-surface temperature (SST) response to Atlantic Meridional Overturning Circulation (AMOC) changes is carried out by varying the strength of northward mass transport at the open boundaries. It is found that the North Brazil Undercurrent (NBUC) reverses its direction in response to a shut-down of the AMOC. Such circulation change allows warm waters of the northern subtropical gyre enter the equatorial zone, giving rise to a prominent warming in the Gulf of Guinea and off the coast of Africa. Sensitivity experiments further show that the SST response behaves nonlinearly to AMOC changes. The rate of SST changes increases dramatically when the AMOC strength is below a threshold value. This nonlinear threshold behavior depends on the position of subsurface temperature gradient. The new RGO is coupled to an atmosphere general circulation model (AGCM) (CCM3.6). The coupled model is capable of capturing major features of tropical Atlantic variability. With the aid of this coupled model, a series of experiments with different combinations of oceanic and atmospheric processes are carried out to elucidate the relative importance of the oceanic processes and atmospheric processes in AMOC-induced tropical Atlantic variability/change. It is found that the oceanic processes are a primary factor contributing to the warming at and south of the equator and the precipitation increase over the Gulf of Guinea, while atmospheric processes are responsible for the surface cooling of the tropical north Atlantic and southward displacement of ITCZ. The sensitivity of the coupled system to different strength of the AMOC is further investigated. It is found that equatorial SST and precipitation response also behaves nonlinearly to AMOC changes. The impact of AMOC changes on Tropical Instability Waves (TIWs) is assessed. It is found that the activity of TIWs is reduced in response to the AMOC-induced equatorial SST warming. Correlation analysis suggests that AMOC may affect TIW activities by modifying SST gradient north of the equator.

Thesis (M.Sc.), Memorial University of Newfoundland, 2000. / Restricted until June 2001. Bibliography: leaves 92-100.