Thesis (Ph.D.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 174-199.

Thesis (M.S.) in Marine Biology--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 65-76).

No description available.

Th.--Sci. nat.--Brest, 1978.

Ce projet s'inscrit dans le programme UVILUQ, le terme inuktitut pour « moule », dont l'objectif est de développer l'utilisation des biopsies liquides chez la moule associée à la bancarisation sur cartes FTA pour le suivi de l'état de santé des écosystèmes côtiers. Cette nouvelle plateforme d'échantillonnage idéale pour les études en milieux éloignés donne accès à une panoplie d'informations sous la forme d'acides nucléiques, dont des biomarqueurs potentiels pour le suivi de l'état de santé des moules. Ce projet s'intéresse à l'un de ces derniers, soit le microbiote bactérien de l'hémolymphe. L'étude du microbiote bactérien chez les espèces sentinelles telles que la moule bleue est un domaine de recherche en expansion. Toutefois, pour pouvoir l'utiliser comme biomarqueur, il est essentiel d'avoir une compréhension étayée de sa variabilité spatiale naturelle à petite échelle afin d'établir des comparaisons de sites valides. Ce mémoire se penche sur la variabilité spatiale à petite échelle de la communauté bactérienne de l'hémolymphe des moules bleues (Mytilus spp.) ainsi que sur les processus biogéographiques sous-jacents. Le premier et seul chapitre présente une étude réalisée dans la moulière de Pointe-Mitis, retrouvée sur la rive sud de l'estuaire du Saint-Laurent, au Canada. Le microbiote de l'hémolymphe de moules provenant de plusieurs aires de la moulière présentant des caractéristiques d'habitat contrastées y a été caractérisé par métataxonomie basée sur l'ARNr 16S, permettant de définir les échelles spatiales de variation et d'avoir un aperçu de l'origine de ces différences. La conclusion générale de ce mémoire revient sur les résultats de cette étude ainsi que sur leur portée quant à l'utilisation potentielle du microbiote bactérien de l'hémolymphe comme biomarqueur. Les perspectives de recherche révélées par cette étude sont également abordées à travers la brève présentation de la deuxième partie de ce projet non incluse dans ce mémoire. Ce projet constitue ainsi un pas de plus vers l'utilisation du microbiote bactérien de l'hémolymphe comme biomarqueur accessible par biopsie liquide pour suivre l'état de santé des écosystèmes côtiers. / This project is part of the UVILUQ program, which mean "mussel" in Inuktitut, aiming to develop the use of liquid biopsy combined with FTA cards to monitor the functional integrity of coastal marine ecosystems. This new sampling method, ideal for remote regions studies, grants access to a large array of potential nucleic acids-based biomarkers to assess how stress factors or xenobiotics impact mussels' health. This project focus on hemolymph bacterial microbiota as one of these potential biomarkers. Studying bacterial microbiota in sentinel species such as blue mussels (Mytilus spp.) is an emerging field of research. However, to use it as a biomarker to evaluate the impact of stress factors, it is essential to have a good understanding of the natural variability at small spatial scales in order to establish valid spatial comparisons. Thus, this thesis is about the small-scale spatial variability of the blue mussels' hemolymph bacterial community and the underlying biogeographical processes. The first and only chapter is a study of the spatial heterogeneity of mussels' microbiota conducted in a local mussel bed in the Canadian St. Lawrence estuary. The hemolymph bacterial community of mussels from different areas presenting contrasting habitat characteristics has been characterized through 16S rRNA gene meta-taxonomy, allowing to identify significant scales of variation and to have a better understanding of the processes behind this variability. The general conclusion of the thesis discusses the results of this study and their implications for the potential use of the hemolymph bacterial microbiota as a biomarker. The research perspectives revealed by this project are also discussed through the brief presentation of the second part of the project that is not included in this thesis. This thesis is another step toward the use of the hemolymph bacterial microbiota through liquid biopsy to monitor the marine coastal ecosystems' integrity.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 113-127. Also available online.

Thesis (Ph.D.)--Murdoch University, 2003. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 154-174.

Background: The blue mussel, Mytilus edulis L., is an important contributor to the shellfish sector of Scottish aquaculture, with 7,270 tonnes worth £8.8 million being produced for the year 2015. Since 2010, production values have fluctuated as a result of inconsistent spat settlement, several business closures, and heightened levels of marine toxins in some areas. On Scotland’s west coast, some farms (most notably Loch Etive) have suffered production losses from the appearance of non-marketable mussels with particularly fragile shells and poor quality meat. Recent research has demonstrated that these undesirable traits have a genetic factor, linked to the presence of a non-native but related species Mytilus trossulus (Gould, 1850) and often its hybrids with the native M. edulis. M. trossulus has been classed as a commercially damaging species under Scottish law, but there is insufficient data on hybridisation and introgression patterns in Scottish mussel populations to evaluate any possible impacts this could have on production. Existing research has focused on single locus genotyping to identify Mytilus spp. and their hybrids in Scotland. By instead utilising multilocus genotyping, introgression could be identified and a better understanding of population structure could be gained, with implications for management to maintain productivity and profitability. The aim of the research presented here was to develop and validate a suite of new species diagnostic markers for multilocus genotyping of field populations of Scottish mussels, thereby establishing a more complete picture of the taxonomic relationships between species than previous studies have permitted. Results: Analysis of SNPs identified with RADseq confirmed the presence of three genetically distinct Mytilus species in Scotland: M. edulis, M. galloprovincialis and M. trossulus. RADseq and KASP genotyping technology successfully identified and validated a suite of 12 highly robust diagnostic SNP markers for multilocus genotyping of Mytilus mussel populations. These markers permitted more comprehensive genotyping than previous studies had, allowing presumed pure species individuals to be distinguished from first generation (F1) hybrids and introgressed (FX) genotypes in reference populations, and subsequently presented the possibility of exploring introgression in a wider scale study. Multilocus genotyping of mussel populations from around Scotland revealed widespread introgression of M. edulis with both M. galloprovincialis and M. trossulus. No pure M. galloprovincialis was identified and pure M. trossulus was restricted to a single site in Loch Etive, possibly part of a relict population. F1 hybrids between M. edulis and M. trossulus were identified in Loch Etive and in Loch Fyne on the west coast. This was evidence of ongoing hybridisation and suggested an active hybrid zone existed in Scotland, something that previous single locus genotyping studies had not acknowledged. A link between shell fragility and M. trossulus introgression was recognised at a single site outside of Loch Etive, but this was not apparent anywhere else and the actual causes of shell fragility remain unevaluated. There was a clear difference between the genetics of most farmed stock and wild populations, which indicated an anthropogenic effect on introgression and subsequent species composition, and had implications for future farm site selection and broodstock sourcing. Temporal species composition in Loch Etive differed over a short time period, but high proportions of M. trossulus alleles were observable some 25 months after a major fallowing event had taken place. Pure M. trossulus was also identifiable, which was consistent with the presence of an established population of M. trossulus existing in this area. Conclusion: Multilocus genotyping has produced a more in depth picture of species diversity in Scottish mussel populations. SNP assays revealed widespread introgression between three genetically distinct species – M. edulis, M. galloprovincialis and M. trossulus – and furthermore recognised that, to date, single locus genotyping has overestimated the abundance of pure Mytilus mussels in Scottish waters. However, this hitherto unidentified genetic complexity does not appear disadvantageous to mussel production, despite the prevalence of M. trossulus introgression among farmed populations, and it is somewhat unlikely that genetics are the sole cause of undesirable shell characteristics among Mytilus spp. mussels.

In this study the effects of the vegetable oils rapeseed, linseed, olive and sunflower oil on mussel performance were investigated. In view of the scarse knowledge of the effects of vegetable oil spills on marine life, unlike petroleum spills which have been extensively studied, this investigation was directed towards an evaluation of the impact of vegetable oil contamination in the marine environment using Mytilus edulis as a bioindicator organism. The growth of mussels, their tolerance to changing salinities and temperatures, their behaviour and vegetable oil metabolism were studied. Fatty acid composition of mussels. microalgae and vegetable oils was also determined. All the vegetable oils studied had an inhibitory effect on the growth of Mytilus edulis, the growth rate of mussels after four weeks of exposure to the oils being 5 times lower than the growth rates of the control mussels. Growth rates were assessed by a photographic method which proved to be practical and provided sufficient precision in detect small increases in growth. Vegetable oils caused mortalities and they changed the fatty acid composition of mussels. Other biological responses of mussels are also affected by sunflower oil exposure: gaping time, tolerance to low salinities and foot extension activity, of which the latter may be of ecological significance. An uptake and accumulation of fatty acids in mussels marked the presence of vegetable oils, however, fatty acid metabolism was only detected after the oils had been removed. The results of this study indicate that contrary to what is believed, vegetable oils should not be overlooked under the argument of their edibility and biodegradability but instead should be included in oil spill contingency planning because they can cause mortality and disrupt the growth of wild and cultured mussels.

No description available.