Willamette Biological Opinion Chinook Reservoir Research 2011

Identification Information

Citation

Originator: ODFW

Publish Date: April 2012

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Jeremy Romer

Job Position: Assistant Project Leader

Telephone: 541-757-4113

E-Mail Address: jeremy.d.romer@odfw.oregon.gov

Description

Abstract: We investigated several life-history characteristics of juvenile Chinook salmon (Oncorhynchus tshawytscha) rearing in Detroit, Cougar and Lookout Point reservoirs to aid in the development of downstream passage options for Willamette Valley Project dams. The study objectives were to provide information on the longitudinal and vertical distribution of juvenile Chinook rearing in reservoirs, relative growth rate, predator/prey interactions, and other population characteristics such as parasitic copepod infection rates. In addition, we tested the feasibility of various gear types and techniques for sampling juvenile Chinook salmon rearing in the nearshore reservoir environment. Information on the smoltification dynamics of juveniles in reservoirs was also collected and will be presented in a separate report when analysis is complete.

Purpose: Biological Opinion (BiOp) that the continued operation and maintenance of the U.S. Army Corps of Engineers (USACE) Willamette Valley Project (WVP) would jeopardize the existence of Upper Willamette River spring Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River steelhead (O. mykiss) (NMFS 2008). The BiOp concluded that lack of fish passage through WVP dams and reservoirs has one of the most significant adverse effects on both species and their habitat. Several Reasonable and Prudent Alternatives (RPA) to the action agencies’ proposed actions were identified in the BiOp to address downstream fish passage concerns, notably, downstream fish passage structures (RPA 2.8; 4.8; 4.8.1; 4.9; 4.10; 4.12), head-of-reservoir juvenile collection facilities (RPA 4.9), and modifications to operational flows to improve conveyance of juvenile fish through the reservoirs. Assessing the feasibility of any of these proposed measures requires a baseline understanding of how juvenile salmonids use reservoir habitat. Understanding juvenile Chinook life-history in WVP reservoirs will also inform other future management actions needed for population recovery. Currently, information regarding juvenile Chinook use of reservoirs, including life stage-specific entrance timing, distribution, migration rate, predator/prey interactions, and growth rates among other population characteristics is limited. In 2010, we began investigations in Cougar and Lookout Point reservoirs to further our understanding of these issues. In 2011, we expanded our scope of sampling to include Detroit Reservoir and refined our techniques to address the critical uncertainties. Several aspects of juvenile Chinook life-history were investigated in this report including; 1) longitudinal and vertical distribution of juvenile Chinook rearing in reservoirs; 2) relative growth rate compared to stream-rearing juveniles; 3) predator/prey interactions; and 4) parasitic copepod infection rates. Results from Detroit, Cougar, and Lookout Point reservoirs are included in this report.

Time Period of Content:

Geographic Extent: Detroit, Cougar and Lookout Point Reservoirs in the Upper Willamette River Basin

Status: Final

Use Constraints:

Format: PDF

Data Quality Information

Lineage-Source: Cooperative Agreement: W9127N-10-2-0008 Task Order Number: 0007 Work Completed for Compliance with the 2008 Willamette Project Biological Opinion, USACE funding: 2011

Data Information

No data information was supplied.

Entity and Attribute Information

Attributes Description: Field attribute information is available in the database table field descriptions.

Is a physical copy maintained for reference at Headquarters? Unknown