Availability of Invertebrate Food Sources for Rearing Juvenile Chinook Salmon in Turbid Susitna River Habitats PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Availability of Invertebrate Food Sources for Rearing Juvenile Chinook Salmon in Turbid Susitna River Habitats PDF full book. Access full book title Availability of Invertebrate Food Sources for Rearing Juvenile Chinook Salmon in Turbid Susitna River Habitats by Tim F. Hansen. Download full books in PDF and EPUB format.
Author: Tim F. Hansen
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 274
Get Book Here
Book Description
Benthic and drifting invertebrates were sampled to evaluate fish food resources and the gain and loss of benthic invertebrate habitat resulting from flow changes.
Author: Tim F. Hansen
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 274
Get Book Here
Book Description
Benthic and drifting invertebrates were sampled to evaluate fish food resources and the gain and loss of benthic invertebrate habitat resulting from flow changes.
Author:
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 164
Get Book Here
Book Description
Author: Laura Gutierrez
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 126
Get Book Here
Book Description
Terrestrial prey subsidies can be a key food source for stream fish, but their importance and environmental controls on their abundance have not been widely documented in high latitude ecosystems. This study investigated terrestrial invertebrate prey availability and predation by age-0+ juvenile chinook salmon (Oncorhynchus tshawytscha), overlap between terrestrial infall and drift to diet, and the relationship between diet to stream temperature and discharge in the Chena River, Interior Alaska. Terrestrial infall, drift, and juvenile chinook diet varied widely through the summers (May-September) of 2008 and 2009. Drift was comprised of 33% terrestrial and 67% aquatic invertebrate mass, while juvenile chinook diet contained 19% terrestrial, 80% aquatic, and 1% unidentifiable invertebrate mass. The proportion of terrestrial invertebrate mass consumed increased through summer and, at times, made up to 39% of total diet. Low similarity of invertebrates in diet and infall, and diet and drift suggested that fish were, in part, prey-selective, selecting hymenopterans and chironomid midges (Diptera). In both years, prey mass consumed and discharge varied inversely, but no correlation was found between proportion of terrestrial invertebrates consumed and discharge. However, the two sampling dates with the highest proportion of terrestrial invertebrates consumed occurred shortly after a 60-year flood, indicating that terrestrial invertebrates may be important during rain and associated high water. This study found that, although terrestrial infall and drift are highly variable, terrestrial invertebrates are an important prey resource for rearing chinook salmon in this high latitude riverine system, especially later in the summer.
Author: Arthur C. Benke
Publisher: Elsevier
ISBN: 0080454186
Category : Nature
Languages : en
Pages : 1168
Get Book Here
Book Description
AWARDS:2006 Outstanding Academic Title, by CHOICEThe 2005 Award for Excellence in Professional and Scholarly Publishing by the Association of American Publishers (AAP) Best Reference 2005, by the Library JournalRivers of North America is an important reference for scientists, ecologists, and students studying rivers and their ecosystems. It brings together information from several regional specialists on the major river basins of North America, presented in a large-format, full-color book. The introduction covers general aspects of geology, hydrology, ecology and human impacts on rivers. This is followed by 22 chapters on the major river basins. Each chapter begins with a full-page color photograph and includes several additional photographs within the text. These chapters feature three to five rivers of the basin/region, and cover several other rivers with one-page summaries. Rivers selected for coverage include the largest, the most natural, and the most affected by human impact. This one-of-a-kind resource is professionally illustrated with maps and color photographs of the key river basins. Readers can compare one river system to another in terms of its physiography, hydrology, ecology, biodiversity, and human impacts.* Extensive treatment provides a single source of information for North America's major rivers* Regional specialists provide authoritative information on more than 200 rivers* Full-color photographs and topographical maps demonstrate the beauty, major features, and uniqueness of each river system* One-page summaries help readers quickly find key statistics and make comparisons among rivers
Author: Jens C. Lovtang
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 210
Get Book Here
Book Description
Chinook salmon (Oncorhynchus tshawytscha) have been absent from their historic spawning and rearing grounds in the Metolius River Basin in central Oregon since 1968, when fish passage was terminated at the Pelton Round Butte Hydroelectric Project on the Deschutes River. Plans have been developed to reestablish passage of anadromous fish through the Project. However, only anecdotal evidence exists on the historic distribution of spring Chinook juveniles in the Basin. A recent approach to characterizing habitat quality for anadromous fishes in the Basin was the development of HabRate (Burke et al. In Press), which presented a relative quality rating of habitat based upon published fish-habitat relationships at the stream reach spatial scale. The present study was initiated to test the predictions of HabRate for summer rearing juvenile Chinook salmon in the Metolius Basin. Chinook salmon fry were released in the winters of 2002 and 2003, and their densities and sizes were quantified via snorkeling and fish collection in six unique study reaches in the upper Metolius River Basin. Each of these stream reaches varied in terms of temperature, habitat availability, invertebrate drift availability, and fish community composition. My observations were not consistent with the qualitative predictions of HabRate. Moreover, habitat utilization was not consistent among study reaches. Similar to other qualitative habitat rating models (e.g. Habitat Suitability Indices (Raleigh et al. 1986) and Instream Flow Incremental Methodology (Bovee 1982)), HabRate's predictions rely solely on physical habitat characteristics, with the assumption that habitat will be used consistently among stream reaches (i.e. a pool in one reach is of equal importance as a pool in another reach). My results suggest that the unique ecological setting of each study reach provides the context for understanding the patterns of growth, habitat use, and diurnal activity of juvenile Chinook salmon. The inclusion of ecological components, such as food availability, the bioenergetic constraints of temperature, and the risk of predation can make these models more biologically realistic. Growth of juvenile Chinook salmon among study reaches had a curvilinear relationship to water temperature, and was also positively related to the drift density of invertebrate biomass. In three collection seasons (fall 2002, spring 2003 and fall 2003) 41 to 69% of the variations in fork lengths were explained by a multiple regression model including temperature and invertebrate drift. Based on these findings, I present a conceptual growth capacity model based on the tenets of bioenergetics as a basis for understanding the relative quality of the habitat among stream reaches for juvenile Chinook salmon. Fish community composition can help to explain observed patterns in habitat utilization and diel activity patterns. In the study reaches that had a greater presence of adult trout (potential predators), observations of juvenile Chinook salmon in mid-channel habitat were infrequent to non-existent during the day and abundances were higher in all habitat types at night. In the study reaches with colder water temperatures, observed juvenile Chinook salmon densities were higher at night. I suggest that habitat selection and diurnal activity patterns in some study reaches are reflective of strategies taken by the fish to minimize risks of predation.
Author: Library of Congress. Exchange and Gift Division
Publisher:
ISBN:
Category : State government publications
Languages : en
Pages : 1136
Get Book Here
Book Description
June and Dec. issues contain listings of periodicals.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 718
Get Book Here
Book Description
Author: Lyman K. Thorsteinson
Publisher:
ISBN:
Category : Coastal ecology
Languages : en
Pages : 110
Get Book Here
Book Description
Provides a synthesis of environmental information on the Yukon Delta, primarily using results from studies conducted since 1983. The synthesis characterizes the major physical properties and resources of the Yukon Delta and identifies regional trends in biological use of major habitats.
Author: Crystal R. Hackmann
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 184
Get Book Here
Book Description
Estuaries provide juvenile salmonids with highly productive feeding grounds, refugia from tidal fluctuations and predators, and acclimation areas for smoltification. However, these dynamic, fluctuating salinity environments may also be physiologically stressful to growing juvenile fish. In order to evaluate the costs and benefits of estuarine marshes to juvenile Chinook salmon, I observed habitat use, diet, and growth of fish in the Nehalem Estuary on the Oregon coast. I also examined physiological costs associated with salmon living in fluctuating salinities and growth rates in laboratory experiments. I collected growth, diet and osmoregulation information from juvenile Chinook salmon in three tidal marsh sites in the Nehalem Bay and from juveniles in the Nehalem River. Stomach contents indicated that a high proportion of the diet is derived from terrestrial prey. These allochthonous prey resources likely become available during the flood stages of tidal cycles when drift, emergent and terrestrial insects would become available from the grasses surrounding the water. This field study confirmed that juvenile Chinook salmon utilized fluctuating salinity habitats to feed on a wide range of items including terrestrial-derived resources. Although field studies indicate that fish in estuarine habitats grow well and have access to quality prey resources, experimental manipulations of salinities were used to quantify the physiological costs of residing in the freshwater-saltwater transitional zone. In the laboratory, I designed an experiment to investigate the physiological responses to fluctuating salinities. Experimental treatments consisted of freshwater (FW), saltwater (SW) (22-25%o); and a fluctuating salinity (SW/FW) (2 - 25%o). These treatments were based on typical salinity fluctuations found in estuarine habitats. I measured length, weight, plasma electrolytes and cortisol concentrations for indications of growth and osmoregulatory function. The fluctuating salinity treatment had a negative effect on growth rate and initial osmoregulatory ability when compared with constant freshwater and saltwater treatments. The results indicated that fluctuating salinities had a small but marginally significant reduction in growth rate, possibly due to the additional energetic requirements of switching between hyper- and hypo-osmoregulation. However, 24-hour saltwater challenge results indicated that all fish were capable of osmoregulating in full-strength seawater. In a second experiment, I manipulated feed consumption rates of juvenile spring Chinook salmon to investigate the effects of variable growth rates on osmoregulatory ability and to test the validity of RNA:DNA ratios as indication of recent growth. The treatments consisted of three different feeding rates: three tanks of fish fed 0.7 5% (LOW) body weight; three tanks fed 3% (HIGH) body weight; and three tanks were fasted (NONE) during the experiment. These laboratory results showed a significant difference in the osmoregulatory ability of the NONE treatment compared to the LOW and HIGH treatments which indicates that a reduction in caloric intake significantly effected osmoregulatory capabilities during a 24 hour saltwater challenge. Furthermore, this suggests that there is a minimum energetic requirement in order to maintain proper ion- and osmoregulation in marine conditions. Estuarine marshes have the potential to provide productive feeding grounds with sufficient prey input from terrestrial systems. However, utilization of these marshes in sub-optimal conditions could alter behavior or impair physiological condition of juvenile Chinook salmon prior to their seaward migration by providing insufficient prey resources in a potentially stressful, fluctuating environment. Therefore, the physiological costs associated with estuarine habitat use should be well understood in order to aid future restoration planning.
Author: Sabrina Garcia
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 27
Get Book Here
Book Description
The northeastern Bering Sea (NBS) is the rearing habitat for juvenile Norton Sound and Yukon River Chinook salmon (Oncorhynchus tshawytscha). In 2002, a marine survey was initiated by the National Oceanic and Atmospheric Administration to study the marine ecology of western Alaska Chinook salmon stocks. Information on the autumn diet (2004–2017) and energetic status (2006–2017) of juvenile Chinook salmon have been collected annually during these surveys to investigate how their feeding and condition respond to changes in the marine environment. During the years observed, juvenile Chinook salmon in the NBS primarily ate fish, including sand lance (Ammodytidae), capelin (Mallotus villosus), and other species, along with smaller proportions of decapods and other invertebrates. Annual average piscivory across all project years ranged from 69% to 96% by mass. Diet composition was size-dependent, and higher proportions of decapods and invertebrates were eaten by smaller juvenile Chinook salmon (
