Proceedings of the 2007 Georgia Basin Puget Sound Research Conference
Session 2B: Salmonid Habitat Use and Recovery
Chair: Fred Goetz
The Early Bird Might Get the Worm, but the Early Sockeye Gets Wormed: Mechanisms and Consequences of Early Freshwater Entry by Fraser River Late-Run Sockeye Salmon.
The Fraser River is the most productive salmon river in Canada, and sockeye are the most economically important salmon in the watershed. Prior to 1996, populations of the Fraser’s late-run sockeye complex were unique in that upon arrival in the Strait of Georgia they milled within the estuary for several weeks prior to entering the Fraser and proceeding to spawning grounds. Since 1996, large proportions of late-run sockeye have entered the Fraser without holding in the estuary, resulting in pre-spawn mortality rates upwards of 95% for early-entry fish. Causes for the mal-adaptive shift in freshwater entry timing are unknown. In 2002, we initiated a multi-year interdisciplinary (ecology, physiology, oceanography, genomic) research program to explore the causes and consequences of early entry. We combine field collections, experimental manipulations, and telemetry tracking to test how individual physiological condition corresponds with timing of river entry and ultimate fate. Initial findings indicate early entry late-run sockeye are characterized by unusual ionic, osmotic, and energetic states, and that advanced sexual maturation appears incompatible with survival in marine waters. Our efforts should yield a predictive model of sockeye migration behavior and survival, which should enable resource managers to optimize management and conservation of these important runs.
Puget Sound Bull Trout Estuarine and Marine Habitat Use – What Have We Learned After Five Years of Study
Bull trout (Salvelinus confluentus) are known as an apex predator in the rivers and streams of the Pacific Northwest. They are also one of three federally listed fish species that are found in the estuarine and marine waters of Puget Sound and the Pacific Coast of Washington. Until 2001 there had been no monitoring or study of these large migratory fish in marine waters of Puget Sound or British Columbia. In 2002 we began a multi-year study of bull trout in all rivers and estuaries of the Puget Sound Distinct Population Segment where bull trout are known to spawn and rear. Our work has focused on estuarine and marine behavior and habitat use of larger juveniles and adults. We use acoustic telemetry, transmitters that emit a coded signal and receivers that detect and record the signal, to follow these mobile animals. To date we have tagged over 250 fish with acoustic tags and have developed a receiver network that covers much of the eastern Puget Sound shorelines and estuaries. We will describe estuarine and marine habitat use of bull trout over the past 5 years of study.
Salmon Recovery Initiatives by the Squamish Nation
The Squamish Nation is deeply tied and connected to the land and waters that encompass their traditional territory and fishing is vitally important to the Squamish culture. As such, the Squamish Nation has a vital interest in management of the fishery and has been instrumental in driving a number of initiatives in the watershed. These are reviewed herein and include: an annual salmon spawner enumeration program; a salmon recovery plan, and a stock assessment framework. Throughout these processes the Squamish Nation has developed successful partnerships with community organizations and government agencies to assist with the long-term goal of salmon recovery in the Squamish River Watershed.
Movement and Behavior of Steelhead (Onchorhynchus mykiss) Smolts Through Hood Canal
Unexplained declines in Hood Canal and Puget Sound steelhead populations have been detected in the last 10 to 20 years, and have been shown to contrast markedly with the relatively stable condition of populations along the Washington and Oregon coasts. This discrepancy between the health of Coastal as opposed to Puget Sound steelhead populations indicates that nearshore smolt migration may constitute a major cause of mortality. Acoustic telemetry was used to investigate survival, migration timing, and migratory behavior of steelhead smolts from four Hood Canal streams and one Strait of Juan de Fuca stream. Estimated survival rates for wild smolts from river mouths to the northern end of Hood Canal was 71% for Skokomish, 67% for Dewatto, and 85% for Big Beef Creek, and 76% for hatchery-reared smolts released into the Hamma Hamma River. Residence time and migration patterns within Hood Canal were highly variable within and among populations. The extended duration of residence in Hood Canal exhibited by some fish suggests that it may provide growth opportunities and function as more than simply a migration corridor. Receivers positioned in nearshore habitats did not detect a disproportionately large number of migrants. Detailed knowledge of steelhead survival and patterns of nearshore habitat use not only aid in determining causes of population decline, but also help define extinction risk and recovery actions for this potentially ESA-listed species.
Puget Sound Cutthroat Trout Marine Migration and Habitat Use
Coastal Cutthroat trout (Salmon clarki clarki) are an anadromous salmonid found throughout the marine waters of Puget Sound. They are more widely distributed in streams and rivers than any other salmonid in Puget Sound. They are also highly sought after by recreational fishers in rivers and estuaries. Even with their widespread presence these fish are one of the least studied salmonids in the waters of Puget Sound. We have begun a multiyear study of the behavior and habitat use of cutthroat trout in the Puget Sound. We use acoustic telemetry, transmitters that emit a coded signal and receivers that detect and record the signal, to follow these mobile animals. We are studying all marine life-stages including smolts, sub-adult and adult cutthroat. Our study areas include Shilshole Bay in Central Puget Sound, South Puget Sound marine shoreline areas, Big Beef Creek and shoreline areas of Hood Canal, and the Skagit River delta and Skagit Bay. We will present preliminary information on the first 1
years of our telemetry study. This work is a companion to a multiyear study of Puget Sound bull trout. We hope the work in this study along with study of bull trout will help inform planners and biologists of the full scope of salmonid habitat use of nearshore marine areas. Comparison of Juvenile Salmon Diets in the Strait of Georgia and Puget Sound 1997-2006.
Juvenile Pacific salmon (Oncorhynchus spp.) enter the ocean in early spring/summer. In the Strait of Georgia and Puget Sound, they generally spend several weeks to months rearing before migrating to other areas. During this time, growth and predation avoidance are the major priorities, and interspecific competition for food could be a limiting factor in successful migration and/or overwinter survival. This report will present the results of 10 years of summer (July) and fall (September) surveys in Puget Sound and the Strait of Georgia, during which stomach data was collected for several thousand juvenile coho (O. kisutch), Chinook (O. tshawytscha), and chum (O. keta) salmon. In addition to examining similarities and differences in dietary preferences, the influence of size, season, and environment will be discussed.