Willamette Biological Opinion Chinook Reservoir Research 2010

Identification Information

Citation

Originator: ODFW

Publish Date: September 2011

Online Link: None

BPA Project #: None

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 life-history characteristics of juvenile Chinook salmon rearing in Cougar and Lookout Point reservoirs. The study objectives were to provide information on juvenile Chinook salmon distribution, relative growth rate, predator/prey interactions, and other population characteristics. In addition, we tested the feasibility of various gear-types and techniques for sampling juvenile Chinook salmon rearing in a reservoir environment. A variety of techniques were necessary to capture juvenile Chinook salmon as reservoir conditions and fish behavior, size, and distribution within the reservoir changed throughout the year. Nighttime snorkel surveys were the least invasive and most productive method to investigate habitat utilization and fry distribution early in the Spring. Minnow traps, hoop nets, Lampara seining, and mid-water trawling were largely ineffective at sampling fry and larger-sized juveniles. Oneida Lake trap nets were the most effective at capturing larger-sized juvenile Chinook salmon when reservoir surface temperatures remained cool.

Purpose: The National Marine Fisheries Service concluded in the 2008 Willamette Project Biological Opinion (BiOp) that the continued operation and maintenance of the 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, head-of-reservoir juvenile collection facilities (RPA 4.9) and modification to operation flows to improve conveyance of juvenile fish through the reservoirs (RPA 2.8; 4.8; 4.8.1; 4.9; 4.10). The feasibility of any of these proposed measures is contingent upon a baseline understanding of how juvenile fish use reservoir habitat. Critical information is needed to determine the feasibility of implementing these RPAs. Currently there is little information regarding juvenile Chinook salmon use of reservoirs, including life stage-specific entrance timing, abundance, distribution, migration rate, predator/prey interactions, and growth rates among other population characteristics.

Time Period of Content:

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

Status: Final

Use Constraints: None

Format: PDF

Data Quality Information

Lineage-Source: U.S. Army Corps of Engineers Cooperative Agreement: W9127N-10-2-0008 Task Order Number: 0002 Work Completed for Compliance with the 2008 Willamette Project Biological Opinion, USACE funding: 2010

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