Diverse fish species consume fruits and seeds in the Neotropics, in particular in the lowland reaches of large rivers, such as the Amazon, Orinoco, and Parana in South America. Floodplains of the Amazon River and its lowland tributaries are characterized by marked hydrological seasonality and diverse assemblages of frugivorous fishes, including closely related and morphologically similar species of several characiform families. Here, I investigated whether or not these fishes are capable of detecting fluctuations in food availability and if they are, how they adjust their feeding strategies. I tested predictions of optimal foraging, limiting similarity and resource partitioning theories with regard to expansion or compression of niche breadth and reduction in trophic niche overlap among species in relation with fluctuations in the availability of alternative food resources. I monitored fruiting phenology patterns to assess food availability and conducted intensive fishing during the high-, falling-, and low-water seasons in an oligotrophic river and an adjacent oxbow lake in the Colombian Amazon. I combined analysis of stomach contents and stable isotope ratios to evaluate dietary patterns, niche breadth, and niche overlap. Diets of six characiform fish species (Brycon falcatus, B. melanopterus, Myloplus asterias, M. rubripinnis, and M. torquatus) changed in a manner that indicated responses to fluctuations in food availability. Feeding strategies during the peak of the flood pulse were consistent with predictions of optimal foraging theory. During times of high fruit abundance, fish preferentially consumed items to which their phenotype is best adapted, maximizing net energy gain and enhancing fitness. As the flood pulse subsided and the availability of forest food resources was reduced in aquatic habitats, there was not a consistent pattern of diet breadth expansion or compression, even though diet shifts occurred, suggesting interspecific differences in foraging efficiencies. Analyses of diets and isotopic ratios revealed a general pattern of increased dietary segregation as the water level receded. Although there never was complete niche segregation among these fishes, these dietary changes effectively reduced interspecific niche overlap. Implications of these results and contribution of allochthonous food resources to diversity maintenance of floodplain fishes are discussed.

The aim of this thesis was to examine the role of diet in ankylosing spondylitis (AS). Patients were examined in: i) a postal questionnaire survey of dietary habits and gastrointestinal (GI) symptoms; ii) a study on biomarkers of diet and disease activity; iii) a comparison of cardiovascular risk factors with the general population using data from the Västerbotten Intervention Programme (VIP), and; iv) a 21-week omega-3 fatty acid supplementation study regarding the effects on disease activity. The postal survey (111 respondents) revealed no correlation between dietary habits and disease activity measured by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). However, GI problems, and in particular GI pain, were prevalent in patients with AS irrespective of NSAID usage.Gastrointestinal pain was predicted by higher BASDAI and a higher consumption of vegetables. Overall, 30 (27%) of the patients experienced an aggravation of gastric symptoms when consuming certain foods. In the study of biomarkers (n=66) no correlation was found between diet and disease activity as assessed by BASDAI. There were, however, positive correlations between BASDAI and the content of arachidonic acid (AA) in plasma phospholipids (rs=0.39, p<0.01) and the estimated activity of the enzyme delta-5-desaturase (rs=0.37, p<0.01). This may reflect a process involved in the inflammation associated with AS that requires further investigation. Comparing data from the VIP for patients (n=89) and controls showed no significant differences regarding diet, physical activity or smoking. Nonetheless, more pronounced correlations between blood lipids and diet were identified among patients than in controls. Furthermore, the levels of cholesterol and triglycerides were lower in patients compared with controls. Lastly, in the supplementation study, a high-dose of long-chain omega-3 fatty acids (4.55 grams/day) was found to lower disease activity, as measured by BASDAI, whereas low-dose treatment (1.95 grams/day) caused no change. In conclusion, within a group of Swedish AS patients we found no correlation between ordinary dietary habits and disease activity. Diet in western populations of patients with AS may, however, be of importance for gastric symptoms and for cardiovascular risk factors. The finding of a lowered disease activity in patients on high-dose supplementation with long-chain omega-3 fatty acids indicates that a radical dietary shift may influence disease activity. The findings of a positive correlation between disease activity and plasma AA, and the decreased levels of blood lipids imply the need for further studies into fatty acid metabolism in AS.

Throughout the twentieth century, Maori life expectancy for both men and women has increased significantly. For most health conditions however, medical statistics show that the Maori mortality rate remains significantly higher than the rate for the NZ non-Maori population. The results of epidemiological studies show that some of these health conditions may be environmentally induced. There appears to be a high incidence of obesity in the Maori population which has been related to dietary intake, with an associated high incidence of diabetes, heart disease and hypertension. These conditions appear to be particularly prevalent among Maori women. It is thought that the Maori population are gentically susceptible to obesity; a trait which manifests itself when there is a plentiful food supply in the population. At present, there is very little information available about the dietary intake of the Maori population, or the effect of diet upon obesity and associated health disorders in this group. The aim of this survey was to obtain information about the dietary intake of a sample of Dunedin Maori women using the diet history method of assessment. Also to determine the incidence of obesity and other dietry related health conditions in this group. Chapter 2 reviews the change in food habits and health status of the Maori population over the last two centuries, as well as reviewing the different methods by which information for dietary surveys is obtained. After setting out the methods and findings of the survey, Chapter 5 discusses the results in light of information obtained from similar dietary studies of NZ women. The samples intake is compared to recommended nutrient allowances for NZ women and the incidence of dietary related health disorders is also discussed. Overall, Dunedin Maori women�s diet was not deficient in any of the recorded nutrients. Dunedin Maori women, in their middle years, exhibited substantially higher energy intakes than middle years non-Maori women in the 1977 National Dietary Survey. The level of Dunedin Maori women�s carbohydrate intake was the main contributing factor for this higher energy intake. Dunedin Maori women over 50 years of age exhibited substantially higher energy intakes than NZ women aged 50-54 years in the 1985 Timaru Health District Survey, with an overall higher consumption of carbohydrate, protein and fat. Over half of Dunedin Maori were classified as overweight or very overweight. Hypertension and diabetes were reported, and obesity was commonly found among women with these health conditions. Over half of Dunedin Maori women used cigarettes, the majority using between ten and thirty cigarettes per day. Dunedin Maori women are relatively isolated from the more densely populated areas of North Island Maori. As a result, the survey results cannot be interpreted as characteristic of NZ Maori women in general. The significance of these findings is rather the elucidation of a regional situation. Further studies of Maori women in both rural and urban areas of the North and South Island are necessary to determine if an overall pattern of high intake exists with a deleterious impact upon the health of Maori women.

Snapper, Pagrus auratus is a valuable coastal fish species in New Zealand and forms an important commercial and recreational fishing industry in the north-east of New Zealand. Previous studies revealed evidence that this carnivorous, primarily benthic feeder consumes a non-indigenous macrobenthic species. Many non-indigenous macrobenthic species have now become established in New Zealand waters. For example, in Rangitoto Channel, Hauraki Gulf, non-indigenous macrobenthic species are prolific, with three bivalve species in particular having thriving populations: Limaria orientalis, Musculista senhousia, and Theora lubrica. The role of these species in the diet of snapper, however, is unknown. To assess the availability of indigenous and non-indigenous prey species to snapper, benthic macrofaunal assemblages throughout Rangitoto Channel were surveyed. To do so, sediment samples were collected at 84 sites. At 24 of these sites sediment was also collected for grain size analysis and at 40 of these sites the seafloor was surveyed with video. To investigate the diet of snapper, fish were collected from four monitoring sites within the channel. Bimonthly monitoring of the diet of snapper as well as the benthic macrofauna was completed at these monitoring sites and trends in the abundance of three prey species, two of which were non-indigenous species, within the sediment and the diet of snapper were compared from June to December 2008. A detailed description of the benthic macrofaunal assemblages throughout Rangitoto Channel confirmed that three non-indigenous species are established throughout this area. The analyses revealed that the diet of snapper has shifted compared to previous studies. Snapper now consume large quantities of two non-indigenous species, M. senhousia and L. orientalis. Consumption of the former species apparently results from its dominance and biomass within the sediment. It is therefore not surprising that snapper consumed large amounts of this species. In contrast, L. orientalis occurred disproportionately in the diet of snapper compared to its abundance within the sediment. I suggest that the establishment of some non-indigenous species benefits snapper.

Snapper, Pagrus auratus is a valuable coastal fish species in New Zealand and forms an important commercial and recreational fishing industry in the north-east of New Zealand. Previous studies revealed evidence that this carnivorous, primarily benthic feeder consumes a non-indigenous macrobenthic species. Many non-indigenous macrobenthic species have now become established in New Zealand waters. For example, in Rangitoto Channel, Hauraki Gulf, non-indigenous macrobenthic species are prolific, with three bivalve species in particular having thriving populations: Limaria orientalis, Musculista senhousia, and Theora lubrica. The role of these species in the diet of snapper, however, is unknown. To assess the availability of indigenous and non-indigenous prey species to snapper, benthic macrofaunal assemblages throughout Rangitoto Channel were surveyed. To do so, sediment samples were collected at 84 sites. At 24 of these sites sediment was also collected for grain size analysis and at 40 of these sites the seafloor was surveyed with video. To investigate the diet of snapper, fish were collected from four monitoring sites within the channel. Bimonthly monitoring of the diet of snapper as well as the benthic macrofauna was completed at these monitoring sites and trends in the abundance of three prey species, two of which were non-indigenous species, within the sediment and the diet of snapper were compared from June to December 2008. A detailed description of the benthic macrofaunal assemblages throughout Rangitoto Channel confirmed that three non-indigenous species are established throughout this area. The analyses revealed that the diet of snapper has shifted compared to previous studies. Snapper now consume large quantities of two non-indigenous species, M. senhousia and L. orientalis. Consumption of the former species apparently results from its dominance and biomass within the sediment. It is therefore not surprising that snapper consumed large amounts of this species. In contrast, L. orientalis occurred disproportionately in the diet of snapper compared to its abundance within the sediment. I suggest that the establishment of some non-indigenous species benefits snapper.

Thesis (Ph.D.)--Tufts University, 2003. / Adviser: Robin B. Kanarek. Submitted to the Dept. of Psychology. Includes bibliographical references (leaves 89-106). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (Ph.D.) -- McMaster University, 1999. / Includes bibliographical references (leaves 303-319). Also available via World Wide Web.

Thesis (Ph.D.) -- McMaster University, 2001. / Includes bibliographical references (leaves 260-279). Also available via World Wide Web.

Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Thesis (Ph. D.)--University of Adelaide, Dept. of Community Medicine, 1987. / Includes bibliographical references (leaves 441-468).