Download or read book Feeding Ecology of and Food Consumption by Juvenile Salmon in Coastal Waters with Implications for Early Ocean Survival written by Richard D. Brodeur and published by . This book was released on 1990 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Estuary and Ocean Productivity Workshop Held at Humboldt State University written by and published by . This book was released on 1990 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sport Fishery Abstracts written by and published by . This book was released on 1991 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fisheries Review written by and published by . This book was released on 1991 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ocean Ecology of North Pacific Salmonids written by William G. Pearcy and published by University of Washington Press. This book was released on 1992 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: A compendium of Northeast Pacific salmon ecology, encompassing all five salmon and two trout species of Oncorhynchus--with Oregon coho salmon, the author's specialty for the past decade, acting as centerpiece. Annotation copyrighted by Book News, Inc., Portland, OR
Download or read book Investigational Report written by and published by . This book was released on 1994 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Feeding in Troubled Waters written by Christina Olga Marie Gulbransen and published by . This book was released on 2014 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Closely related species divide shared resources to reduce interspecific competition and to allow for coexistence when resources are limiting. Upon ocean entry, juvenile pink and chum salmon coexist in mixed schools and feed on similar prey. The diet of juvenile pink and chum salmon during their first two months at sea in the coastal waters of the Broughton Archipelago, British Columbia, was described for 2003 and 2006. Full stomach rankings suggested a lack of prey limitation in both years. Stomach content analysis revealed a greater diet separation among pink and chum in 2003 than in 2006. Species specific prey preferences were observed. Electivity comparisons of prey consumed with prey available in the plankton indicated selective feeding in both species. Considering the importance of diet in the survival of juvenile salmon and ultimately in adult recruitment, an understanding of prey conditions provides insight into salmon population trends in the region.
Download or read book Research in Fisheries written by and published by . This book was released on 1989 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book North American Journal of Fisheries Management written by and published by . This book was released on 1995 with total page 1022 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bulletin International North Pacific Fisheries Commission written by and published by . This book was released on 1990 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trophic Niche and Foodweb Dynamics Within and Among Juvenile Salmon Species in Years of Contrasting Ocean Conditions written by Erica Jenkins and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The ecological niche of a population is dynamic and will be affected by changes in the ecosystem and as a population migrates. An ontogenetic niche shift can also occur as organisms grow and can include changes in morphology, habitat, and feeding behaviour. Although they are the two most abundant salmon species, and are further augmented through hatchery stocking, it is unclear the degree to which the niches of juvenile pink salmon (Oncorhynchus gorbuscha) and chum salmon (O. keta) overlap. Furthermore, juvenile pink salmon and chum salmon undergo a period of rapid growth during their first summer at sea and it is unclear how their ecological niche changes with their ontogeny. Understanding the foodweb dynamics of juvenile salmon in the coastal marine environment is important because a large proportion of the overall mortality of salmon is thought to occur during their first summer at sea. The purpose of this study is to determine the degree to which the niches of juvenile pink salmon and chum salmon overlap, how their trophic position and food source changes as they grow into a new ontogenetic niche, and how these processes are affected by ocean conditions. I expected that years of poorer feeding conditions and increased competition would result in reduced trophic position and greater overlap of the niches of juvenile pink salmon and chum salmon. I hypothesized that juvenile salmon would shift their diet to a more offshore-based foodweb as they grew and that their trophic position would increase with size, but that the shift would be stronger when feeding conditions were improved. Statistical analysis showed evidence that the overlap of the niches of pink salmon and chum salmon increased when the abundance of salmon was high. Contrary to expectations, the trophic position of salmon appeared to decrease under favourable conditions. The trophic position of both pink salmon and chum salmon was higher in the southern portion of the study area, and increased when juvenile abundance was high. I suggest that the higher trophic position among juvenile salmon when there is more competition might result from increased reliance on gelatinous zooplankton, which are carnivorous, but a nutritionally poor food choice compared to other common prey items. The ontogenetic shift from summer to fall among juvenile salmon included a shift to a more offshore-based diet and a higher trophic position. In the northern portion of the study area, which was comprised of the southern reaches of the Alaska Coastal Current (ACC), the shift to an offshore-based food source was more pronounced than the trophic shift. In the southern portion of the study area, which included the Transition Domain (TD) between the ACC and the California Current System (CCS), the shift to a higher trophic position was more pronounced than the shift in food source. The results of this study suggest that if climate change leads to poorer feeding conditions, the niches of pink salmon and chum salmon may increasingly overlap when the abundance of these species is high. Hatchery stocking of these species may also contribute to this trend if it leads to a greater abundance of juvenile salmon in the coastal marine environment. There is evidence that the structure of the food web and the nature of the ontogenetic niche shift are very different in the ACC and the TD, and climate change and hatchery stocking will most likely affect these regions differently.
Download or read book Bulletin International North Pacific Fisheries Commission written by International North Pacific Fisheries Commission and published by . This book was released on 1992 with total page 814 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summary of U S S R U S Cooperative High Seas Salmonid Tagging Operations in 1990 written by Robert Victor Walker and published by . This book was released on 1990 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1991 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1990 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecosystem Approaches for Fisheries Management written by Alaska Sea Grant College Program and published by . This book was released on 1999 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physiological Ecology of Pacific Salmon written by Cornelis Groot and published by UBC Press. This book was released on 2010-10-01 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Every year, countless juvenile Pacific salmon leave streams and rivers on their migration to feeding grounds in the North Pacific Ocean and the Bering Sea. After periods ranging from a few months to several years, adult salmon enter rivers along the coasts of Asia and North America to spawn and complete their life cycle. Within this general outline, various life history patterns, both among and within species, involve diverse ways of exploiting freshwater, estuarine, and marine habitats. There are seven species of Pacific salmon. Five (coho, chinook chum, pink, and sockeye) occur in both North America and Asia. Their complex life histories and spectacular migrations have long fascinated biologists and amateurs alike. Physiological Ecology of Pacific Salmon provides comprehensive reviews by leading researchers of the physiological adaptations that allow Pacific Salmon to sustain themselves in the diverse environments in which they live. It begins with an analysis of energy expenditure and continues with reviews of locomotion, growth, feeding, and nutrition. Subsequent chapters deal with osmotic adjustments enabling the passage between fresh and salt water, nitrogen excretion and regulation of acid-base balance, circulation and gas transfer, and finally, responses to stress. This thorough and authoritative volume will be a valuable reference for students and researchers of biology and fisheries science as they seek to understand the environmental requirements for the perpetuation of these unique and valuable species.
