Author: John Heinrich EilerPublisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 107
Book Description
Stock Composition, Run Timing, and Movement Patterns of Chinook Salmon Returning to the Yukon River Basin in 2004
Author: John Heinrich EilerPublisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 107
Book Description
Stock Composition, Run Timing, and Movement Patterns of Chinook Salmon Returning to the Yukon River Basin in 2003
Author: Bering Sea Chinook Salmon Bycatch Management, Regulatory Impact Review/initial Regulatory Flexibility Analysis
Author: Distribution and Movements of Chinook Salmon, Oncorhynchus Tshawytscha, Returning to the Yukon River Basin
Author: John Heinrich EilerPublisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 296
Book Description
[Cont.] Although not surprising considering the extensive variation in migration rates observed among individual fish, this finding does suggest that these pulses do not represent cohesive aggregates of fish moving upriver. Unlike the well established methods used to estimate other life history characteristics, the development of quantitative methods for analyzing and modeling fish movements has lagged noticeably behind, due in part to the complexity associated with movement data and (prior to the advent of telemetry) the difficulty of collecting this type of information on free-ranging individuals. Two fundamentally different analytical approaches, hierarchical linear regression models and multivariate ordination, were used during this study to evaluate factors thought to influence the upriver movements of the fish. In spite of the inherent differences, both methods provided strikingly similar results, indicating that the study findings were not dependent on the approach used, and suggesting that the results were plausible based on the information available and the weight of evidence. Both analytical methods had advantages, and provided complementary information. With hierarchical linear models, it was possible to simultaneously evaluate a wide range of explanatory variables (in our case, both biological and environmental), which provided standardized comparisons and simplified the interpretation of the results. Since both fixed and random effects were incorporated in the models, it was possible to account for sources of variation when insufficient information was available to identify the underlining factors - an important consideration since few field studies provide comprehensive data. With multivariate ordination, separate analyzes were needed to examine the relationships between the migration rates and the biotic and physical variables. In addition to being cumbersome, this limitation made it more difficult to compare the relative influence of the different factors and interactions between factors. However, ordination was very useful as an exploratory tool. Although compartmentalized by stock, across fish comparisons were simple and relatively straightforward. Because the explanatory variables were evaluated separately in relation to the ordination score assigned to the fish, it was possible to examine and compare highly correlated variables. Ordination was also able to identify overall patterns within the data and assess the relative importance. While this can be accomplished within the framework of linear regression using mixture models to determine whether multiple distributions exist within the data, the process is much simpler with ordination. The migratory patterns of the fish were influenced by a wide range of factors, with evidentiary support for complex, multi-faceted relationships. Physical features of the basin demonstrated stronger explanatory power, accounting for over 70% of the observed variation in migration rate compared to 18% for the biological characteristics of the fish. Parameter estimates associated with the steepness of the migratory route and remaining distance the fish had to travel to reach their natal rivers were most strongly correlated with migration rate, with consistent relationships observed across stocks. Migration rates were also noticeably slower in extensively braided reaches of the basin. The weaker relationships between migration rate and biotic factors may reflect stabilizing selection on long-distance migrants. Smaller fish exhibited minimally faster swimming speeds on average than larger individuals. This relationship was stronger in highly braided reaches. Run timing was positively related to migration rate for most stocks. Surprisingly, upper basin stocks traveling farther upriver displayed progressively negative relationships, suggesting that late-run fish were moving slower. Ancillary information suggests that this decline may relate to deteriorating fish condition later in the season.
Scientific Reports of Soviet Whaling Expeditions in the North Pacific, 1955-1978
Author: Phil ClaphamPublisher:
ISBN:
Category : Whaling
Languages : en
Pages : 168
Book Description
Distribution and Movement Patterns of Chinook Salmon Returning to the Yukon River Basin in 2000-2002
Author: Forecasting Stock-specific Upriver Migration Timing of Chinook Salmon in the Yukon River
Author: Bryce Douglas MecumPublisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 80
Book Description
Pacific salmon (Oncorhynchus spp.) are an economically and culturally important genus of fishes endemic to the North Pacific. Their sustainable management depends on an understanding of the drivers of their abundance and migration dynamics. In many instances, statistical models are employed to predict abundance and run timing before harvest takes place to more effectively meet management objectives. In this thesis, I created a general-purpose predictive model of run timing that can be applied to many salmon populations. I then applied it to Yukon River Chinook salmon (O. tshawytscha) by generating pre-season predictions of inriver run timing, which I then compared with existing observations of run timing at two upriver locations. Prediction errors were low enough for the model to be useful to management. Models such as the one created in this study represent an objective tool that can be used to reduce subjectivity in fisheries management.
Project Operational Plan: Characterization of the Distribution, Run Timing, and Abundance of Nushagak River Chinook and Sockeye Salmon Using Radiotelemetry
Author: Michael Raymond LinkPublisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 51
Book Description
A brief overview of the chinook and salmon fisheries in the Nushagak River and their management begins this document. The remainder describes a research plan for a study that will take place in 2006 at the river using radio tag detection in order to identify major spawning tributaries, estimate the proportion of spawning salmon in those tributaries, describe stock-specific run-timing patterns, and estimate system-wide abundance of sockeye salmon returning to the Nushagak River. The software to be used is Telemetry Manager produced by LGL.
Winter-run Chinook Salmon in the Sacramento River, California with Notes on Water Temperature Requirements at Spawning
Author: Daniel W. SlaterPublisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 20
Book Description
Salmon specialists throughout the Pacific Coast indicate that the winter-run Chinook salmon is restricted to California's Sacramento River system. The characteristics and habits of the race are unique in the following respects: Fresh-water holding period, December to April; spawning period, April into July. The up-migration is concurrent with the late segments of the fall run, but the adults are distinguishable by the green condition of the gonads. The down-migration is concurrent with that of the spring-run fry, but the migrants are 2-inch or larger fingerlings. Evidence is lacking to determine whether there is an earlier down-migration of fry. The race appears to hold great promise as a stock to be introduced into areas where May-August temperatures are 42.5 degrees - 57.5 degrees F., for it supports superb angling during the fresh-water holding period. Water temperatures in May through August are seen as the factor limiting the natural extension of the range of the race.
Run Timing, Fat Content and Maturity of Spring- and Fall-run Klamath River Chinook Salmon (Oncorhynchus Tshawytscha)
Author: James W. HearseyPublisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 138
Book Description