Download or read book Early Marine Distribution of Out migrating Juvenile Sockeye Salmon Oncorhynchus Nerka written by Nicole Gerbrandt and published by . This book was released on 2013 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The early marine phase is a critical period for out-migrating juvenile sockeye salmon (Oncorhynchus nerka). They undergo physiological changes while entering into a new environment, and this is thought to be a period of high mortality. This study examined factors affecting swimming depth as juveniles migrated through Rivers Inlet, and compared swimming depth at the point of ocean entry and life history strategies in sockeye salmon from Rivers Inlet and nearby populations on the Central Coast of British Columbia. Most juvenile sockeye salmon swam within two meters of the ocean's surface during their out-migration through Rivers Inlet, and were slightly deeper later in the out-migration. In addition, in a mesocosm experiment, Rivers Inlet juvenile sockeye salmon did not alter their swimming depth in response to increasing salinity at their preferred swimming depth, despite experiencing negative physiological effects when swimming in highly saline waters. Similar data on other nearby sockeye salmon populations were collected. Juvenile sockeye salmon from populations that out-migrate through brackish waters tended to be smaller than individuals from populations that leave fresh water and enter directly into highly saline marine environments, and they too tended swim within the top two to four meters of the surface. This shows that conditions in the top 4 m of the water's surface represent actual conditions experienced by out-migrating juvenile sockeye salmon in the early marine environment and is a critically important observation in terms of understanding such issues as prey availability, the potential role of brackish surface layers in coastal fjords, lagoons and estuaries, and susceptibility to predators. These findings will inform future sampling efforts on these populations, and also suggest that these populations maintain varying life history characteristics which enable them to survive early marine conditions within the top 4 m of the ocean.
Download or read book Distribution Abundance and Growth of Juvenile Sockeye Salmon Oncorhynchus Nerka and Associated Species in the Naknek River System 1961 64 written by Robert J. Ellis and published by . This book was released on 1974 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Factors Influencing the Early Marine Ecology of Juvenile Sockeye Salmon O Nerka in Rivers Inlet British Columbia written by Seana Leigh Buchanan and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Rivers Inlet sockeye salmon (Oncorhynchus nerka) population was historically the third most numerous in British Columbia, with returns routinely exceeding one million adults. In recent years, the population has drastically declined, culminating in an utter failure of the adult spawning population in 1999, when returns were estimated at 3600 fish. Poor marine survival has been proposed as the primary cause of the decline. Existing evidence, including concurrent declines in sockeye salmon populations from nearby watersheds indicate the problem may lie in the early marine phase. We provide evidence suggesting that a crucial, population-limiting window may exist in the early marine phase, as the newly smolted juvenile sockeye salmon emerge into Rivers Inlet and nearby waters. Unless appropriate abiotic conditions exist in the lead-up to the juvenile migration, the brood year may suffer significant mortality. This, I propose, is a key contributor to reduced returns of Rivers Inlet sockeye salmon.
Download or read book Distribution Abundance and Growth of Juvenile Sockeye Salmon Oncorhynchus Nerka and Associated Species in the Naknek River System 1961 64 written by Bruce L. Wing and published by . This book was released on 1974 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Distribution Abundance and Growth of Juvenile Sockeye Salmon Oncorhynchus Nerka and Associated Species in the Naknek River System 1961 64 Classic Reprint written by Robert J. Ellis and published by Forgotten Books. This book was released on 2016-10-08 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Distribution, Abundance, and Growth of Juvenile Sockeye Salmon, Oncorhynchus Nerka, and Associated Species in the Naknek River System, 1961-64 In the summers of 1961 to 1963, juvenile sockeye salmon in the pelagic areas had a characteristic pattern of abundance. For the entire system: abundance (catch per tow) of age 0 increased from early summer to midsummer and then declined to late August. The abundance in late August varied about threefold and, in general, was independent of variations in the number of parents from 1960 to 1963. In July the abundance of age 0 fish in each basin was proportional to the amount of known contiguous spawning ground, but by late August this relation no longer existed. This change was at least partly due to migration of the age 0 fish - generally from basins of greater abundance of fish to those of lesser abun dance. The larger and faster growing fish were the first to migrate. Not all basins were involved in these migrations. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Download or read book History of the Fishery and Summary Statistics of the Sockeye Salmon Oncorhynchus Nerka Runs to the Chignik Lakes Alaska 1888 1966 written by Michael L. Dahlberg and published by . This book was released on 1979 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecological Drivers of Variation in Juvenile Sockeye Salmon Marine Migrations written by Cameron Freshwater and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Animal migrations are often associated with high mortality due to increased energy expenditure, reduced foraging opportunities, and increased predation risk. Migratory traits such as body size, phenology, or use of stopover habitats may moderate individual risk to mortality mechanisms and influence patterns of survival. However, variability in migratory traits is rarely quantified in detail because tracking many individuals over large areas is logistically challenging. In this dissertation, I used otoliths to examine migratory variability among and within sockeye salmon (Oncorhynchus nerka) populations, a species that has recently experienced declines associated with poor survival during juvenile marine migrations. Broadly, I examined the individual and environmental drivers of migratory patterns, as well as how variation across ecological scales (individuals, populations, and years) contributed to migratory diversity. First, I conducted a laboratory study to validate the use of otolith microstructure techniques in sockeye salmon post-smolts. Next, I assessed how a suite of ecological processes could interact to create a latitudinal gradient in sockeye salmon body size. By reconstructing individual growth and migration histories I determined that variation in size was correlated with ocean entry size and phenology, rather than differential marine growth or size-selective mortality. I then used estimates of migratory rate from otoliths to demonstrate that juvenile sockeye salmon exhibited distinct migratory phenotypes associated with ocean entry traits. Larger individuals migrated rapidly offshore, while smaller fish reared for several weeks in nearshore regions. Furthermore, a subset of the smallest individuals entered the ocean late in the year, migrated particularly slowly, and may have overwintered on the continental shelf. These linkages between ocean entry and migratory traits suggest juvenile sockeye salmon exhibit substantial migratory plasticity associated with carry-over effects from freshwater residence; however juvenile salmon may also respond strongly to variable conditions in marine habitats. In my fifth chapter, I compared marine growth and migration phenology in years with low and high competitor densities. After accounting for freshwater density-dependent effects, growth rates were similar in both years, but mean migration rates were nearly 50% faster in the high-density year. Migratory behavior may be used to buffer individuals from the effect of competitive interactions. In my final chapter, I sampled 16 Fraser River sockeye salmon populations to explore variation in the timing and duration of early marine migrations. Although populations differed in downstream migration timing, as well as their duration of residence within nearshore habitats, there was substantial variation within each population and between sampling years. These findings suggest individual characteristics and stochastic processes interact with population-specific strategies to shape migratory phenologies in this metapopulation. Management actions should account for and preserve migratory diversity at multiple ecological scales to maintain resilient salmon populations into the future.
Download or read book On the Orientation of Young Sockeye Salmon Oncorhynchus Nerka During Their Seaward Migration Out of Lakes written by Cornelis Groot and published by . This book was released on 1965 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Assessment of the Juvenile Sockeye Salmon Oncorhynchus Nerka Populations of Babine Lake written by Jeremy M. B. Hume and published by Cultus Lake, B.C. : Fisheries and Oceans Canada, Science. This book was released on 2000 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Juvenile sockeye salmon rearing in Babine Lake were re-examined 22 years after the initiation of the Babine Lake Development Project (BLDP). Abundance, distribution, size, and species composition of the limnetic fish populations, including juvenile sockeye salmon, were determined by hydroacoustic and midwater trawl surveys in the autumn of 1993 and the summer and fall of 1994 and 1995 and compared to results collected before and shortly after the start of the BDLP. Our objectives were to look for: 1) changes in the abundance of juvenile sockeye relative to spawning numbers; 2) changes in the utilization of the available nursery area; and 3) the effects of increased popualtion size and density on the size and growth of juvenile sockeye.
Download or read book Distribution Abundance and Growth of Juvenile Sockeye Salmon Oncorhynchus Nerka and Associated Species in the Naknek River System 1961 1964 written by Robert J. Ellis and published by . This book was released on 1974 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pacific Salmon Life Histories written by Cornelis Groot and published by UBC Press. This book was released on 1991 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pacific salmon are an important biological and economic resource of countries of the North Pacific rim. They are also a unique group of fish possessing unusually complex life histories. There are seven species of Pacific salmon, five occurring on both the North American and Asian continents (sockeye, pink, chum, chinook, and coho) and two (masu and amago) only in Asia. The life cycle of the Pacific salmon begins in the autumn when the adult female deposits eggs that are fertilized in gravel beds in rivers or lakes. The young emerge from the gravel the following spring and will either migrate immediately to salt water or spend one or more years in a river or lake before migrating. Migrations in the ocean are extensive during the feeding and growing phase, covering thousands of kilometres. After one or more years the maturing adults find their way back to their home river, returning to their ancestral breeding grounds to spawn. They die after spawning and the eggs in the gravel signify a new cycle. Upon this theme Pacific salmon have developed many variations, both between as well as within species. Pacific Salmon Life Histories provides detailed descriptions of the different life phases through which each of the seven species passes. Each chapter is written by a scientist who has spent years studying and observing a particular species of salmon. Some of the topics covered are geographic distribution, transplants, freshwater life, ocean life, development, growth, feeding, diet, migration, and spawning behaviour. The text is richly supplemented by numerous maps, illustrations, colour plates, and tables and there is a detailed general index, as well as a useful geographical index.
Download or read book Variation in the Early Life History of Sockeye Salmon Oncorhynchus Nerka written by Caryn A. Abrey and published by . This book was released on 2005 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Juvenile Bristol Bay Sockeye Salmon Ecology written by Edward Vincent Farley (Jr.) and published by . This book was released on 2008 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Predicting annual returns of Bristol Bay sockeye salmon (Oncorhynchus nerka) has been difficult due to large, unexplained variations in return strength. Ocean conditions, particularly during the first few months after salmon leave freshwater, are believed to have a strong influence on their early marine growth and survival. Limited historical and present research suggests that sea temperature can affect juvenile Bristol Bay distribution. During years with cool spring sea temperatures, juvenile sockeye salmon are distributed nearshore along the Alaska Peninsula, whereas they are found further offshore during years with warm spring sea temperatures. Juvenile sockeye salmon are larger, in better condition, and have higher marine stage survival after the first year at sea when they are distributed further offshore than when they are distributed nearshore along the Alaska Peninsula. Juvenile sockeye salmon stomach contents also shift from primarily Pacific sand lance (Ammodytes hexapterus) and euphausiids to age 0 walleye pollock (Theragra chalcogramma) when their distribution changes from nearshore to further offshore. Annual averages of juvenile sockeye salmon growth rate potential (GRP) were generally lower among years and regions with cool spring sea temperatures. In addition, juvenile sockeye salmon GRP was generally higher in offshore regions than nearshore regions of the eastern Bering Sea shelf. A sensitivity analysis indicated that juvenile sockeye salmon GRP was more sensitive to changes in observed (August to September) sea surface temperatures during years when prey densities were lower. The results of the dissertation suggest that variability in early marine survival is primarily due to bottom-up control of the trophic structure of the eastern Bering Sea ecosystem"--Leaf iii.
Download or read book NOAA Technical Report NMFS SSRF written by and published by . This book was released on 1976 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecology and Behavior of Juvenile Sockeye Salmon Oncorhynchus Nerka in Bristol Bay and the Eastern Bering Sea written by Richard R. Straty and published by . This book was released on 1973* with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A History of Sockeye Salmon Research Karluk River System Alaska 1880 2010 written by Richard Gard and published by . This book was released on 2014 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Distribution and Origin of Sockeye Salmon oncorhynchus Nerka in Offshore Waters of the North Pacific Ocean written by Robert R. French and published by . This book was released on 1976 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt:
