Author: Anna Edith Steel Publisher: ISBN: 9781321807394 Category : Languages : en Pages :
Book Description
Juvenile Chinook salmon (Oncorhynchus tshawytscha) experience high rates of mortality as they out-migrate, frequently navigating through rivers heavily modified by human activities. Understanding patterns of movement and survival is key to informing management decisions in these human-dominated aquatic systems. Ultrasonic telemetry is a valuable tool allowing us to observe the movement patterns of aquatic animals. The first chapter of this dissertation examines the performance of an ultrasonic telemetry positioning system by comparing receiver arrays deployed in three diverse environments. It suggests that researchers utilizing a positioning system should focus on testing the geometry of receivers before the study begins, as well as minimizing receiver movements and maximizing the accuracy of speed-of-sound estimates. The second chapter uses an ultrasonic positioning system to observe the route selection of juvenile out-migrants at an artificial juncture in the tidal portion of the Sacramento River, California. The strongest predictor of ultimate migratory route was the relative water velocity at the river's junction with the water diversion channel. The third chapter describes patterns in survival through a segment of the lower Sacramento River. We applied a previously derived analytical model, the mean free-path length model, in a new way to determine whether predator densities or prey behaviors were more indicative of fine-scale mortality rates. The model indicated that the hatchery smolt were highly directional in their outmigration behavior, leading us to conclude that spatial patterns in survival of juvenile Chinook were driven by increasing density or efficiency of the predator community. Ultrasonic telemetry technologies can be valuable in habitats where direct observation of animals is difficult, including in large river systems such as the Sacramento River. Through the continuing advancement of these technologies, their careful application, and the appropriate union of empirical data and modeling approaches, we can provide valuable information about the movements and mortality patterns of species of conservation concern.
Author: Natalie N McNair Publisher: ISBN: Category : Languages : en Pages :
Book Description
Outmigration is an important life stage for Chinook salmon (Oncorhynchus tshawytscha) survival in the Sacramento River, and yet our understanding of their behavior and needs during this time is limited. To gain a better understanding of their survival and movement rates during outmigration, late fall run Chinook salmon smolts were tracked using acoustic telemetry techniques. Habitat features were measured and quantified throughout the study area to evaluate how Chinook salmon respond to key levee features including shade, instream woody material, and aquatic vegetation. The overall average movement speed through the entire study area was 0.77 m/s with an overall survival of 86%. Based on multiple linear regressions, vegetation was found to have the largest effect on speed with fish slowing down with increased vegetation cover. Shade, river mile, and velocity also had significant effects on movement speeds, but instream woody material was not significant. The result for woody material was surprising since it was anticipated to have a large impact on movement speeds. A positive correlation was found between faster fish movement speeds and higher survival. No evidence of diel movement patterns was found after releasing the fish. These finding can help managers create sites better designed to help Chinook salmon in the Sacramento River system. Results from this paper indicate that the type of woody material being installed might not be appropriate for this life stage of salmon.
Author: Gabriel P. Singer Publisher: ISBN: 9781658413169 Category : Languages : en Pages :
Book Description
Riverine ecosystems around the world have undergone extensive anthropogenic alterations, often to the detriment of native aquatic biodiversity. Migratory fishes are particularly vulnerable to habitat fragmentation and degradation. For example, Chinook Salmon populations in the Sacramento and San Joaquin Rivers, CA have been declining for nearly a century. Its Mediterranean climate, position in a landscape dominated by urban and agricultural land use, and the presence of an inland delta that serves as the hub of California's vast water conveyance system, makes this a particularly perilous region for migrating juvenile salmon. These studies use acoustic telemetry as tool to investigate survival and routing of juvenile fall and spring-run Chinook salmon during their riverine and estuarine migratory phases in the Sacramento and San Joaquin Rivers. Survival to the ocean in these river systems is already lower relative to other Chinook Salmon populations in North American. Tracking studies included investigations of the sub-lethal effects of tagging fish with acoustic transmitters, movement ecology and survival of two distinct evolutionary significant units of Chinook Salmon during an historic drought, and the movement ecology and survival of a reintroduced population of Chinook Salmon in the San Joaquin River.
Author: United States. Office of the Assistant Secretary of the Army (Civil Works) Publisher: ISBN: Category : American River Watershed (Calif.) Languages : en Pages : 1756
Author: Daniel W. Slater Publisher: 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.
Author: Anna Edith Steel
Author: Natalie N McNair
Author: Gabriel P. Singer
Author: United States. Office of the Assistant Secretary of the Army (Civil Works)
Author: 
Author: Bertrand H. Lemasson
Author: Pamela Ann Petrusso
Author: Sara E. Anzalone
Author: 
Author: Daniel W. Slater