| Summary: | M.S. University of Hawaii at Manoa 2013. Includes bibliographical references. Between the 1960s and 2000s, a substantial decline of Alaskan harbor seals (Phoca vitulina richardsi) and Steller sea lions (Eumetopias jubatus) prompted studies to enhance conservation and understanding of harbor seal and Steller sea lion population dynamics. The purpose of this study was to search the literature and establish a nutrient database that could be utilized in captive settings as well as a predictor for wild pinniped populations. With the aid of the MIXIT-WIN ration formulation program and the nutrient database of common northern Pacific and Alaskan marine mammal prey items, the nutrient composition of various mixed prey diets were assessed and the nutritional impact on the decline of Alaskan pinniped populations were evaluated. The nutrient variation within and between species of the various prey included in the nutrient database were evaluated, by comparing location, gender, age, season and size. Based on literature findings, different forage fish species had significantly different chemical compositions, in addition, to mineral and fatty acid concentration variability. The MIXIT-WIN ration formulation program, along with the nutrient database of selected prey, demonstrated how changes in both proportions and nutrient densities of each prey altered the nutrient content of the diet. Different mixed diet proportions of herring to pollock, suggested that low fat (LF) capelin could satisfy gross energy (GE) levels compared to high fat (HF) capelin. However, if a diet needs to contain more pollock at a 1:5.5 ratio, the ideal diet would need to contain HF Pacific herring and HF pollock. In addition, the impact of prey availability and quality in the wild population, by prey substitution, suggested that HF mackerel could serve as a substitute for capelin, HF smelt could serve as a substitute for Pacific herring and only HF Atlantic herring could serve as a substitute for Pacific herring, based on crude fat/lipid (CF) and GE ...
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