Estuarine Habitat and Juvenile Salmon: Current and Historical Linkages in the Lower Columbia River and Estuary
Abstract
Our studies in the lower 100-km of the Columbia River estuary quantified historical habitat changes and provided new information about contemporary abundance patterns, life histories, and habitat associations of Chinook salmon. The conceptual framework for this research defined salmon performance in the estuary as the product of three factors: habitat opportunity, habitat capacity, and the structure/life histories of source populations. Our 2002-2008 survey results provided empirical data to support this framework by quantifying Chinook salmon performance in terms of temporal abundance, life history and stock-group diversity, foraging success, and growth, as well as by quantifying the relationships between stock groups and one or more of these factors. In Part I, we detail our reconstruction of historical habitat opportunities and changes in the estuary as influenced by the tide, river flows, and temperature. In Part II, we depict contemporary habitat opportunities based on present-day patterns of salmon distribution and abundance and upon various physical factors that influence fish access to shallow-water rearing areas. In Part III, we compare the capacity of different wetland and nearshore habitats in supporting juvenile Chinook salmon as indicated by variations in prey availability, salmon diet, and rates of consumption. Finally, in Part IV, we examine the effects of upriver population structure and life histories on estuary rearing behavior and performance, including the genetic sources of individual Chinook salmon found within particular habitats and stock-specific patterns of residency and growth. These surveys provided new information about the present estuarine habitat associations of juvenile salmon. They also provided data for estimates of historical change in habitat conditions, estimates of historical change in salmon life histories, and analyses of food webs. Below we summarize major conclusions drawn from these evaluations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2011
- Accession Number
- ADA581333
Entities
People
- António M. Baptista
- Daniel L. Bottom
- David A. Jay
- Edmundo Casillas
- George Mccabe
- Jennifer Burke
- Lance Campbell
- Mary A. Lott
- Regan Mcnatt
- Susan Hinton
Organizations
- National Oceanic and Atmospheric Administration