Pacific harbor seals (Phoca vitulina richardii) are one of Oregon’s most common coastal predators, numbering between 10,000 and 12,000 individuals (Brown et al. 2005b). They consume more than 149 species or types of marine prey within the Pacific Northwest, which include a large variety of commercially important fisheries species. Despite...
In the last decade, the California Current Large Marine Ecosystem has experienced a trend of increased severity of upwelling-driven coastal hypoxia. This thesis strove to examine the potential upper trophic level impacts of moderate and severe hypoxia in the CCLME. Initially I conducted a literature review of Pacific harbor seal...
Pacific walrus (Odobenus rosmarus) are particularly vulnerable to the impacts of climate change due to the high reliance on sea ice for safety, transport, and social behaviors. Additionally, the walrus diet consists of predominantly bivalves, whose populations are in decline as a result of ocean acidification. We first determined the...
Today, there are six extant species of sea lion around the world, with the seventh (the Japanese sea lion) already having gone extinct due to a lack of proper conservation management. Because each of the surviving 6 sea lion species differ slightly in their anatomy, behavior, reproduction, and local habitats,...
California and Steller sea lions (Zalophus californianus, Eumetopias jubatus, respectively) are considered sentinel species because they have long life spans, are long-term coastal residents, feed at high trophic levels, and have large blubber stores that serve as depots for anthropogenic toxicants. There are few studies on sea lion health and...
Foundation species are important components of ecosystems because they provide habitat and ameliorate stressful conditions for residents. This thesis considers the role of surfgrasses (Phyllospadix spp.) as dynamic foundation species on the coast of Oregon in two studies. Chapter 2, which presents an observational survey of two Phyllospadix congeners, investigates...
Year-round habitat use of marine predators provides knowledge of important marine areas throughout different life stages. Large-scale, environmental variability, both in space and time, causes changes in the behavior and distribution of marine predators that are important to quantify for conservation. In the Northern California Current System (NCCS), common murres...