Download or read book Factors Influencing Zooplankton Populations in Alaskan Sockeye Salmon Oncorhynchus Nerka Nursery Lakes written by Jon Nicholas Sweetman and published by . This book was released on 2001 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The relative importance of sockeye salmon, invertebrate predators, and other environmental factors in structuring the size and abundance of zooplankton populations was examined in a series of 23 lakes from southern Alaska. Zooplankton abundance was strongly related to sockeye density, along with nutrient availability and alkalinity. The mean size of Bosmina longirostris, the dominant herbivorous cladoceran, was positively correlated with the abundance of the predatory copepod, Cyclops columbianus. Changes in the size and abundance of Bosmina remains over the past 300-500 years were then determined for sediments from two lakes on Kodiak Island, Alaska. The zooplankton communities showed varying responses to past changes in salmon populations, resulting from relative changes in the magnitude of adult salmon-derived nutrient loading and in predation pressure from juvenile sockeye and cyclopoid copepods. Knowledge of how various factors impact zooplankton can have important implications for the effective management of sockeye within these lake systems"--Leaf 3.
Download or read book Some Aspects of the Comparative Ecology of Fishes Associated with Juvenile Sockeye Salmon Oncorhynchus Nerka Walbaum in the Lakes of the Naknek River System Alaska written by Richard L. Wallace and published by . This book was released on 1969 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of the distribution, relative abundance and diet of fishes sympatric with juvenile sockeye salmon, Oncorhynchus nerka (Walbaum), within the freshwater nursery areas of the Naknek River system was undertaken from 1961 to 1963. The study was part of an extensive investigation to determine what factors in the freshwater environment were limiting the size of the populations of sockeye salmon returning to the rivers of Bristol Bay, Alaska. The speties found associated with juvenile salmon in the limnetic zones of the Naknek system were the pond smelt, Hypomesus olidus (Pallas); the least cisco, Coregonus sardinella Valenciennes; the threespine stickleback, Gasterosteus aculeatus Linnaeus; and the ninespine stickleback, Pungitius pungitius (Linnaeus). Life history information was collected for these sympatric species. Tow nets were used to capture samples of fish from the limnetic portions of the nursery areas. Some samples were collected by beach seines, lake traps and otter trawls. Plankton samples were collected and compared to the diets of the limnetic fishes. Although some confusion has existed in the literature, I concluded that pond smelt of the Naknek system belong to Hypomesus olidus (Pallas). The populations of smelt were comprised of six age-groups in the late summer, but most specimens belonged to three age-groups. Most members of the species spawn in the spring of the fourth year of life. The estimated fecundity ranged from 900 to 4,300 eggs per female. Seven age-groups of least ciscoes were present in the populations of the Naknek system. The species in the Naknek system probably spawned for the first time in the fall of their fourth year. The estimated fecundity of two specimens was 4,006 and 14,380 eggs. Populations of three spine stickleback were comprised of three age-groups of fish. I was unable to assign ages to ninespine stickleback. Estimates of the fecundity of the species ranged from 116 to 456 eggs per female. All species studied were distributed throughout the Naknek system. The relative abundance of the fishes studied was variable between and within nursery areas and from year to year. The population densities of pond smelt and threespine stickleback were larger in the surface waters compared to the deep waters. The relative abundance of sockeye fry, yearlings and ninespine stickleback was greater in the surface stratum rather than the deep stratum in most nursery areas. The five main food items utilized by these limnetic species were cladocerans (Bosmina sp. and Daphnia sp.); copepods (cyclopoid copepods and Diaptomus sp.); and Dipteran insects. Analysis of the similarity of diets indicated that the diets of sockeye fry and pond smelt were more similar than were the diets of sockeye fry or yearlings and any other sympatric species. The diet of sockeye fry was more similar to that of either species of stickleback than was the diet of sockeye yearlings. An analysis of the food of various sizes of each species of fish indicated the diets of three age-groups of smelt were more similar than the diets of various age-groups of any other fish. The food composition of three age-groups of ciscoes and two size groups of both species of stickleback showed a strong positive correlation. The diets of sockeye fry and yearlings showed the weakest positive correlation of the species studied. All species of fish studied selectively fed on one or more components of the zooplankton. Daphnia sp. and cyclopoid copepods were strongly selected in Lake Coville. Cyclopoids were selected in South Bay. Bosmina sp. was selected from the waters of West End. In Lake Coville, the greatest potential competition for food probably existed between the large populations of pond smelt and sockeye fry. In the West End nursery area, potential competition between juvenile salmon and both species of stickleback may not be severe, depending on the age composition of the salmon population present in the nursery area. The possibility exists that the relatively low numbers of adult sockeye salmon returning to the comparatively rich lakes of the Naknek River system is due to the presence of large populations of sympatric species of fish. Each of these sympatric species feed on the same general types of food organisms as do the juvenile salmon and may affect the numbers of young salmon that leave the lake, and subsequently return from the ocean.
Download or read book Factors Influencing Production of Sockeye Salmon Oncorhynchus Nerka in Lakes of Southwestern Alaska written by Robert Louis Burgner and published by . This book was released on 1964 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Developing a Research and Restoration Plan for Arctic Yukon Kuskokwim Western Alaska Salmon written by National Research Council and published by National Academies Press. This book was released on 2005-07-06 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent declines in the abundance of salmon in the Arctic-Yukon-Kuskokwim (AYK) region of western Alaska have created hardships for the people and communities who depend on this resource. In 2002, the AYK Sustainable Salmon Initiative (SSI) was created to undertake research to understand the reasons for this decline and to help support sustainable management in the region. This report makes recommendations for developing the research that the AYK SSI science plan should be based on, and relates the development of a restoration plan to the results of that research.
Download or read book Crustacean Zooplankton Abundance and Species Composition in 13 Sockeye Salmon Oncorhynchus Nerka Nursery Lakes in British Columbia written by D. Paul Rankin and published by . This book was released on 1980 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Species Profiles written by Gilbert B. Pauley and published by . This book was released on 1989 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crustacean Zooplankton Abundance and Species Composition in 13 Sockeye Salmon Oncorhynchus Nerka Nursery Lakes in British Columbia written by D. P. Rankin and published by . This book was released on 1980 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crustacean zooplankton abundance and species composition in 13 Sockeye salmon Oncorhynchus Nerka nursery lakes in British Columbia written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sockeye Salmon Oncorhynchus Nerka written by Canada. Department of Fisheries and Oceans and published by Fisheries and Oceans, Information and Publications Branch. This book was released on 1987 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: A three-day symposium was organized by the Department of Fisheries and Oceans and convened at Nanaimo, British Columbia in November 1985. Advice on subject matter and participation came from an external committee of senior scientists and administrators in contributing agencies in Canada, Japan, the United States, and the Union of Soviet Socialist Republics. The papers included in the proceedings deal with sockeye biology and stock management. Papers on sockeye biology are divided into those concerned primarily with life history strategies and enhancement and development. Papers dealing with management are divided into the tools of management and management of some principal stocks.
Download or read book Growth and Survival of Sockeye Salmon Introduced Into Ruth Lake After Removal of Resident Fish Populations written by William R. Meehan and published by . This book was released on 1966 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crustacean Zooplankton Ambundance and Species Composition in 13 Sockeye Salmon Oncorhynchus Nerka Nursery Lakes in British Columbia written by Ashton, H. J and published by Nanaimo, B.C. : Government of Canada, Fisheries and Oceans. This book was released on 1980 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Marine derived Nutrients on Population Dynamics of Sockeye Salmon Oncorhynchus Nerka written by Tadayasu Uchiyama and published by . This book was released on 2006 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The effects of marine-derived nutrients (MDN) on the productivity of sockeye salmon (Oncorhynchus nerka) stocks in Alaska were examined through nitrogen stable isotope analysis of smolts and mathematical models of the sockeye stock-recruit relationship. Smolt 8 [delta]15N was used to infer the degree to which smolts depend on MDN for their growth. We attempted to identify the characteristics of sockeye nursery lakes and watersheds that affect the availability of MDN to juvenile sockeye using multiple regression. Stock-recruit models incorporating MDN effects were fit to sockeye escapement-return data to test if fluctuations in sockeye stock productivity could be explained by changes in MDN input into nursery lakes. The magnitude of escapement and water residence time were the most important factors affecting the MDN availability to juvenile salmon. Mixing state of lakes and the distance from the coast were also found to significantly affect the MDN availability. We found that regional environmental fluctuations had a large effect on stock productivities in stock-recruit modeling. However, we did not find strong evidence to support our hypothesis that increases in MDN input to nursery lakes will result in increased productivity of sockeye stocks. Stock-recruitment data may be poorly suited to detection of the influence of MDN"--Leaf iii.
Download or read book Feeding Ecology of Juvenile Sockeye Salmon in Afognak Lake Alaska written by Natura Richardson and published by . This book was released on 2016 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much attention has been given to juvenile Sockeye Salmon (Oncorhynchus nerka) ecology with particular focus on pelagic food webs in deep nursery lakes. In contrast, this study took place at Afognak Lake, Alaska, to better understand juvenile Sockeye Salmon foraging ecology, potential consumer interactions, and metabolic opportunities and constraints in a shallow nursery lake. I collected fish every two weeks from Afognak Lake from May through August, 2013. I described ontogenetic and temporal variation in the diets of juvenile Sockeye Salmon and a potential competitor, adult Threespine Stickleback (Gasterosteus aculeatus). Notably, this study revealed that adult aquatic insects are an important prey item for lake rearing juveniles. Threespine Stickleback diets showed some overlap with diets of juvenile Sockeye Salmon; however, significant differences in diet composition suggest that Sockeye Salmon and Threespine Stickleback partition prey and habitat resources. I then used my field-derived temperature, demographic, and diet data as inputs to a bioenergetics model to estimate summer consumption rate and growth efficiency of juvenile Sockeye Salmon from Afognak Lake across a range of foraging scenarios. Consumption rate was greater and mean growth efficiency was lower for all littoral-use scenarios relative to pelagic-use scenarios. Further, daily consumption was lowest and mean growth efficiency was highest for model scenarios in which insects were a dominant component of the diet relative to scenarios in which zooplankton were the dominant prey. My findings highlight the importance of benthic-pelagic coupling in Sockeye Salmon nursery lakes and the potential for juveniles to navigate trade-offs between energy acquisition and thermal conditions across lake habitats.
Download or read book The Food of Juvenile Sockeye Salmon Oncorhynchus Nerka Related to the Zooplankton in Iliamna Lake Bristol Bay Alaska written by Stephen Holly Hoag and published by . This book was released on 1968 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Assessment of Lacustrine Productivity Relative to Juvenile Sockeye Salmon Oncorhynchus Nerka Production in Chignik and Black Lakes written by Gary B. Kyle and published by . This book was released on 1992 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reports on the results of limnological investigations of general water-quality parameters, nutrients, phytoplankton, zooplankton, and fall fry, which were conducted in Chignik and Black Lakes during 1991 to characterize lake productivity relative to juvenile sockeye salmon (Oncorhynchus nerka) production, historical information, and other sockeye nursery lakes.
Download or read book Factors Affecting Sockeye Salmon Oncorhynchus Nerka Growth in Four Lakes of the Fraser River System written by J. C. Goodlad and published by . This book was released on 1974 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selective Predation on Zooplankton and the Factors that Affect Sockeye Salmon Growth in Lake Aleknagik Alaska written by Kirsten Work and published by . This book was released on 1992 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
