Thesis (Ph.D.)--Memorial University of Newfoundland, 2002. / Bibliography: leaves 11-1-11-48.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2002. / Bibliography: leaves 108-114.

Marked shifts in the life history traits of fish have been reported in many exploited fish stocks, with a particular trend towards decreasing size and age at maturity. Though other environmental and behavioural factors have been implicated, the key driver of these changes links to fishing pressure, through both the direct selective effects of fishing itself, and indirectly through the manipulation of important biological and environmental factors. Although reproduction itself has been well described in teleosts, the mechanisms of environmental and endogenous entrainment of maturation remain unclear and it was the principal aim of this thesis to improve current understanding of these systems in gadoids. Photoperiod has been identified as the strongest environmental cue for entraining seasonal behaviours, including seasonal reproduction. Over the last decade, several of the key drivers involved in the photoneuroendocrine cascade have been elucidated in mammals and birds, with the Eya3 pathway merging as an important mechanism for entraining maturation. However, little is yet known of their influence on maturation in fish. In the first study, the photoperiodic regulation of the Eya3-Tshβ-Dio2 cascade was analysed in Atlantic cod exposed to either continuous light (reproductive inhibition) or simulated natural photoperiod (reproductive stimulation) from July to December. Monthly expression was measured through QPCR, demonstrating a strong activation of pituitary Eya3 under declining photoperiod. As this coincided with the onset of secondary gametogenesis, these results suggest that Eya3 may play a stimulatory role in the photoneuroendocrine cascade of Atlantic cod. Although photoperiod represents the most reliable and noise free proximate signal to entrain the reproductive process, it is clear that a minimum growth and energetic state must be reached for maturation to progress. This directed the second line of study – a series of diet restriction trials on haddock and cod designed to investigate the influence of naturally occurring lipid levels in the diet on growth and reproduction, define the “critical window” in which fish assess their energetic state and how this is analysed before commencing secondary gametogenesis, and to assess whether Eya3 is regulated by the growth axis in cod. The results of these experiments indicate that overall size around the autumn equinox is the most accurate indicator of maturation commitment in cod. Additionally, Eya3 expression was elevated in maturing fish indicating a role for this marker in linking the energetic signal with entrainment of the reproductive axis. Finally, an analysis of the physiological and genetic stock structure of cod from the North Sea IVa stock region and westward into VIa was performed. The results of this analysis support previous genetic studies, indicating further fine-scale structuring of these stocks, reflective of the structure indicate by the differences in maturation strategies of the component populations. The results identified both environmental and harvest related pressures which may be driving the current stock structure. The results of these studies greatly improves our understanding of the key drivers and mechanisms regulating maturation in cod, highlighting new avenues for future research.

L'utilisation d'une source d'alcali forte, telle que l'hydroxyde de sodium (NaOH), au cours du blanchiment au peroxyde d'hydrogène (H2O2) des pâtes mécaniques a pour inconvénient majeur de solubiliser certains composés du bois. Or, cette matière organique dissoute (MOD) induit une forte valeur de demande chimique en oxygène (DCO) dans les effluents de blanchiment. De plus, une fraction de cette matière organique, nommée DCO récalcitrante (R-DCO), n'est pas biodégradable dans les stations de traitement des eaux usées industrielles. Cette étude a prouvé qu'il était possible d'atteindre la blancheur cible de 75 % ISO en substituant partiellement le NaOH par l'hydroxyde de magnésium (Mg(OH)2) ou le carbonate de magnésium (MgCO3) lors du blanchiment en un stade au peroxyde d'hydrogène d'une pâte TMP d'épicéa. Parallèlement, la consommation en peroxyde d'hydrogène diminuait fortement lors des blanchiment à base de Mg(OH)2 et MgCO3. La DCO a ainsi été réduite de 26 et 31%, respectivement, pour les blanchiments alternatifs en comparaison du blanchiment conventionnel. En outre, seulement 10 et 8 kg O2.ton-1 de R-DCO ont été générés au cours des procédés de blanchiment à base de Mg(OH)2 et MgCO3 contre 13,3 kg O2.ton-1 lors du procédé conventionnel. L'analyse par chromatographie à exclusion stérique couplée à l'absorbance UV, la fluorescence et au carbone organique dissous (HPSEC/UVA-Fluo-COD) a permis de montrer que la MOD dans les effluents de blanchiments conventionnel et alternatifs était caractérisée par les mêmes masses moléculaires. Ces travaux ont également mis en évidence que les blanchiments alternatifs avec des sources d'alcali à base de magnésium affectaient la résistance de la pâte blanchie. Il a été montré que l'indice de rupture diminuait de 10% par rapport à la pâte blanchie de manière conventionnelle. Par ailleurs, la réversion de blancheur de la pâte blanchie avec une source d'alcali alternative a diminué de 2% ISO durant le photo-vieillissement à la lumière. L'analyse structurelle de la lignine a également permis de comprendre les mécanismes réactionnels mis en jeu en fonction de la source alcaline utilisée au cours du blanchiment. Dans le cas d'une pâte chimicothermomécanique (CTMP d'érable), il est envisageable de remplacer totalement le NaOH avec différentes sources d'alcali alternatives mais au détriment des propriétés physiques de la pâte (-25 et 16% sur l'indice de rupture et déchirement). / The use of a strong alkali source, such as sodium hydroxide (NaOH), during hydrogen peroxide (H2O2) bleaching of mechanical pulps is responsible for the solubilization of some wood components. Yet, this dissolved organic matter (DOM) induces a high value of chemical oxygen demand (COD) in the bleaching effluents. In addition, a fraction of this organic matter, called recalcitrant COD (R-COD), is not biodegradable in industrial wastewater treatment plants. This study has proven that it was possible to reach the brightness target of 75% ISO during a one stage peroxide bleaching of spruce TMP when NaOH was partially substituted by magnesium hydroxide (Mg(OH)2) or magnesium carbonate (MgCO3). Meanwhile, hydrogen peroxide consumption decreased significantly during Mg(OH)2- and MgCO3-based bleachings. COD has been reduced by 26 and 31%, respectively, during alternative bleachings in comparison with the conventional one. Furthermore, only 10 and 8 kg O2.t-1 R-COD were generated during Mg(OH)2- and MgCO3-based processes respectively against 13.3 kg O2.t-1 during the conventional process. DOM analysis by size exclusion chromatography coupled with UV absorbance, fluorescence and dissolved organic carbon (HPSEC/UVA-Fluo-DOC) has shown that the MOD in conventional and alternative bleaching effluents were characterized by the same molecular weights. This work has also pointed out that alternative bleachings with magnesium-based alkali sources affected bleached pulp strength properties. A reduction up to 10% of the tensile index was measured compared to the conventional bleached pulp. Otherwise, the brightness reversion of alternative bleached pulps decreased by 2% ISO during photo-ageing under UV irradiation. Structural analysis of lignin enabled us to understand reaction mechanisms brought into play during alternative bleaching. In the case of a chemithermomechanical pulp (CTMP maple), it is feasible to completely replace NaOH by different alternative alkali but at the expense of the strength properties of the bleached pulp (-25 and 16 % on tensile and tear indexes).

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-09-19T19:36:42Z No. of bitstreams: 1 DayanneLopesGomes_TESE.pdf: 3794439 bytes, checksum: 0ba5d82fec6f4ee029b8a8f00861a539 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-09-19T22:05:18Z (GMT) No. of bitstreams: 1 DayanneLopesGomes_TESE.pdf: 3794439 bytes, checksum: 0ba5d82fec6f4ee029b8a8f00861a539 (MD5) / Made available in DSpace on 2017-09-19T22:05:19Z (GMT). No. of bitstreams: 1 DayanneLopesGomes_TESE.pdf: 3794439 bytes, checksum: 0ba5d82fec6f4ee029b8a8f00861a539 (MD5) Previous issue date: 2017-07-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A urolit?ase afeta aproximadamente 10% da popula??o mundial e est? associada fortemente a forma??o de cristais de oxalato de c?lcio (CaOx). Atualmente n?o existe nenhum composto eficiente que possa ser utilizado para prevenir esta doen?a. No entanto, os polissacar?deos sulfatados (PS) de algas possuem a capacidade de alterar a carga superficial dos cristais de CaOx e assim modificar a din?mica da cristaliza??o, devido ? intera??o das cargas negativas desse pol?mero com a superf?cie do cristal durante sua s?ntese. Nestre trabalho foi verificado o efeito de quatro popula??es de PS extra?dos da alga verde Caulerpa cupressoides var. flabellata na forma??o de cristais de CaOx in vitro. Os PS extra?dos foram nomeados de CCB-F0.3, CCB-F0.5, CCB-F1.0 e CCB-F2.0. An?lises de microscopia eletr?nica de varredura e de potencial zeta mostraram que os polissacar?deos extra?dos modificam a morfologia, o tamanho e a carga superficial dos cristais de CaOx formados na presen?a dos PS. Todos os PS de C. cupressoides induziram o aumento da quantidade de cristais CaOx formados. Contudo, com exce??o de CCB-F2.0, a presen?a dos demais PS levou ? forma??o de cristais de CaOx dihidratados (COD), que s?o comuns em pessoas n?o formadoras de c?lculos. Al?m disso, esses cristais COD apresentaram morfologia arredondada ou em formato de halteres. As an?lises de infravermelho, miscroscopia de fluoresc?ncia, citometria de fluxo e a an?lise de composi??o at?mica (EDS) permitiram a proposi??o de um modelo de intera??o entre os PS de Caulerpa e os cristais COD. Neste modelo, a distribui??o de PS na estrutura do cristal de CaOx ideal para que haja maior estabiliza??o dos cristais COD ? de 2:1:1 entre a base: ?pice: face. Acredita-se que nessa distribui??o os PS consigam evitar a desidrata??o dos cristais COD, tornando-os mais est?veis. Este estudo ? o primeiro passo para entender as intera??es entre PS de C. cupressoides e os cristais de CaOx, que s?o a principal causa de c?lculos renais. / Urolithiasis affects approximately 10% of the world population and is strongly associated with calcium oxalate (CaOx) crystals. Currently, there is no efficient compound that can be used to prevent this disease. However, seaweeds? sulfated polysaccharides (SPs) have the ability to change the CaOx crystals surface?s charge and thus modify the crystallization dynamics, due to the interaction of the negative charges of these polymers with the crystal surface during their synthesis. We observed that the SPs of C. cupressoides modify the morphology, size and surface charge of CaOx crystals. Thus, these crystals are similar to those found in healthy persons. In the presence of SPs, dihydrate CaOx crystals showed rounded or dumbbell morphology. Infrared analyzes, fluorescence microscopy, flow cytometry (FITC-conjugated SPs) and atomic composition analysis (EDS) let us propose the mode of action between the Caulerpa?s SPs and the CaOx crystals. This study is the first step in understanding the interactions between SPs, which are promising molecules for the treatment of urolithiasis, and CaOx crystals, which are the main cause of kidney stones.

Cod, haddock and whiting are among the most economically important species in the Scottish demersal fishery. Juvenile settlement, the transition from pelagic to demersal habitat, has been identified as an important milestone for these species, but there is insufficient knowledge and data about this life stage. It is believed that the period of settlement has an impact on recruitment success, as important density-dependent processes may take place, such as competition for suitable substrate, refuge or prey. Also, knowledge of settlement timing and duration is relevant to understanding population connectivity and thus to the development of successful conservation measures. Sampling was conducted between April and August 2004, June and September 2005 and June and July 2006 at an inshore site off the east coast of Scotland. Over 4000 0- group cod, haddock and whiting were collected. Comprehensive morphometric and dietary analyses of the samples were carried out, followed by statistical analysis of the data. The results suggested clear differences in the patterns of settlement between the different species. Initially juvenile haddock favoured deeper, further offshore locations, while cod occupied shallower, inshore waters. Whiting settled much later in the season and over protracted period of time. Furthermore, cod showed an affinity for structured habitat, while haddock and whiting were found only over sand. The results also showed that the transition from the pelagic to the demersal habitat was associated with clear and progressive changes in the prey composition of the juvenile fish. The results also showed temporal, spatial and dietary niche segregation of settling juveniles, which is expected to reduce competition for resources and increase the potential for settlement success.

Cod hatcheries rely greatly on wild-caught broodstock as egg quality from farm-reared broodstock tends to be poor. Broodstock diet and levels of essential fatty acids have been linked to fecundity and egg quality in cod. Arachidonic acid (ARA) and astaxanthin (Ax) are important nutrients linked to fish egg quality and differences in levels have ben found between eggs from wild and farmed cod. The aim of this thesis was to investigate the impact of dietary supplementation with ARA and Ax on fecundity and egg quality in cod. The first experiment investigated the effect of feeding a diet supplemented with ARA, for 1, 2 or 3 months prior to peak spawning. Results showed that supplementation increased ARA in eggs and that Groups fed the supplement had improved fecundity and egg quality (though with no correlation between the duration of supplementation and number/quality of eggs). The second experiment investigated the effect of supplementation of Ax in broodstock diets on egg quality in farmed cod and showed that Ax was taken up into eggs and that fish fed supplemented diet had improved fecundity and egg quality. The third experiment compared the effect of diet supplementation with ARA and Ax on egg quality in wild and farmed cod and showed that despite the dietary supplementation, wild origin fish performed better on a number of egg quality and fecundity indices. However, it was not possible to take the greater ages and spawning experience of the wild broodstock into account, which may have influenced the results. The fourth experiment measured lipid and fatty acid profiles of eggs from two UK cod hatcheries. Variation was found between farms and across seasons. Results showed that supplementation of cod broodstock diet with ARA and Ax had a positive impact on egg quality and fecundity, although effects were not consistent across all egg quality parameters.

Capelin (Mallotus villosus (Müller, 1776)) is an important marine forage fish species that typically inhabits sub-Arctic and temperate circumpolar waters. Capelin have recently been reported in greater abundance in Arctic regions, and are considered an indicator for warming climate in the northern marine ecosystem. The goal of this thesis is to examine intrinsic factors among capelin populations, and whether niche overlap among sympatric capelin and Arctic cod (Boreogadus saida (Lepechin, 1774)) will affect the abundance and persistence of capelin in the Arctic as temperatures continue to rise. Life history comparisons of capelin from two Arctic regions (Western Beaufort Sea, Cumberland Sound) relative to a sub-Arctic population (Newfoundland) show that body size, body condition, growth rate and age-at-maturity vary among these regions. Life history characteristics that are adapted to northern environments and increasing temperatures will allow the presence and persistence of this species to increase in the Arctic. The consequence of increased abundance of capelin in the Arctic environment could be competition between capelin and Arctic cod, an Arctic species within a similar dietary niche. Stomach contents indicated that both species feed primarily on calanoid copepods and this result was corroborated with high dietary overlap in isotopic bivariate space (carbon and nitrogen stable isotopes). The occurrence of capelin is expected to increase in the Arctic with rising temperatures, thus adaptation in life history traits in capelin specific to each region may facilitate increased abundance and persistence, and possibly contribute to competitive pressure on Arctic cod. Potential competition will be particularly important in nearshore and shelf habitats where shifts in availability of intermediate trophic level taxa will influence diet and distribution of key predators such as beluga, sea birds, and anadromous fishes. As the Arctic environment changes with climate shifts, newly adapted or dispersed species from sub-Arctic systems are expected to drive shifts in ecosystem structure and function in the marine environment. / October 2016

Arctic Cod, Boreogadus saida (Lepechin 1774) occur throughout the circumpolar north at all levels of the water column depending on their life history stage, the time of day, the season, and their activity. Arctic Cod are the most abundant fish species in the Canadian Beaufort Sea (CBS) ecosystem, and are an important link in the flow of energy within the food web. This study examined differences in energy acquisition and usage in Arctic Cod among three depth zones in the CBS (from 15-800m) by examining stomach contents and physiological indicators, taking into account sex, age and body size. Nonparametric comparison analyses found no differences with depth, but support for an ontogenetic shift in diet regarding prey size, a difference in energy content of an average diet between size classes 1 (30-60mm) and 2-4 (2: 60-90mm; 3: 90-120mm; 4: >120mm), and a slight positive relationship between physiological indicators and body size. / October 2016

A large portion of U.S. inmates and parolees experience co-occurring substance use and mental health disorders (COD). Offenders with COD exhibit significantly poorer outcomes than offenders who do not have COD, including less time to rearrest and reincarceration. Research shows that transition services for substance use and mental health disorders improve parolee outcomes, yet a majority of offenders with COD do not receive transition services prior to discharge or upon release from correctional facilities. Using a nationally representative sample of offenders with COD (secondary data from the CJ-DATS; N=811), this study analyzes the treatment effects of Transition Case Management (TCM) on parolees' drug use, rearrest, and reincarceration during the first nine months of parole, on a sample of offenders with COD. Results indicate there are no statistically significant differences between TCM treatment and control groups when predicting likelihood of rearrest, reincarceration, and drug use.