PROJECT TITLE: Evaluate spawning of fall Chinook and chum salmon just below the four lowermost Columbia River mainstem dams.

PROJECT GOAL:  The continuing purpose of this on-going project is to assess the extent of spawning by ESA-listed chum and fall Chinook salmon in the mainstem Columbia River so that the Federal Columbia River Power System (FCRPS) can be managed to protect and enhance these important populations.  Our primary focus is to determine what conditions must exist to provide successful spawning and rearing below mainstem dams and what measures must be taken to protect those fish.

PROJECT COORDINATION:  This is a cooperative project implemented under 5 BPA contracts with the Oregon Department of Fish and Wildlife (ODFW), Pacific States Marine Fisheries Commission (PSMFC), U.S. Fish and Wildlife Service (USFWS), U.S. Geological Survey (USGS), and Pacific Northwest National Laboratory (PNNL).

PROJECT OBJECTIVES:  This project has four biological objectives (see below).   Objectives listed here correspond to the Biological Objectives presented in Section 6 of the proposal submitted under the Mainstem/Systemwide Province for funding in FY2007-2009.  All four objectives will be addressed simultaneously over the three year period covered by this proposal as a series of tasks conducted by ODFW, PSMFC, USFWS, USGS, and PNNL.  Continued implementation of this project will result in an improved understanding of the relationship between operation of the FCRPS and protection of mainstem spawning salmon populations.  Funding will allow continued in-season management of the hydrosystem, reducing harm to mainstem spawning and incubation.  We have developed a series of tasks designed to inform regional fish managers regarding status and trends of mainstem spawning populations of chum and fall Chinook salmon.  These tasks will allow us to collect and report on abundance and productivity metrics, spatial structure, and genetic diversity that are essential for describing population viability and trends in abundance.  They will further our understanding of the spawning habitat requirements for these fish, especially as they relate to hydrosystem operation.  

PROJECT OBJECTIVE 1 - Describe abundance, spatial and temporal distribution, and possible stock origins of chum and fall Chinook salmon spawning in the mainstem Columbia River.  (Responsible Agencies: ODFW, PSMFC, PNNL)

PROJECT OBJECTIVE 2 - Describe abundance, spatial and temporal distribution, and possible stock origins of chum and fall Chinook salmon spawning in Columbia River tributaries downstream from The Dalles Dam.  (Responsible Agency: PSMFC)

PROJECT OBJECTIVE 3 - Describe emergence timing, and size at and time of emigration from local rearing areas.  (Responsible Agencies: ODFW, PSMFC, PNNL)

PROJECT OBJECTIVE 4 - Describe physical habitat use and requirements for fall Chinook salmon in the Columbia River downstream from The Dalles, John Day, and McNary dams and for chum salmon downstream from Bonneville Dam.  (Responsible Agencies: USFWS, USGS, ODFW, PSMFC, PNNL)

There are 64 well defined tasks or subtasks under these 4 objectives listed in Section F of the proposal (with the responsible agency shown for each task).    Each agency takes the lead on specific tasks based on special skills and/or knowledge in those areas.  To summarize, Pacific States Marine Fisheries Commission leads the adult portion, Oregon Department of Fish and Wildlife leads the juvenile portion, U.S. Fish and Wildlife Service leads the habitat portion, PNNL contributes to adult, juvenile and habitat work and USGS is responsible for the redd superimposition work.

USGS CONTRACT DESCRIPTION:

All work elements for the USGS SOW fit under Project Objective 4, for chum salmon only.

Background:
One consequence of hydrosystem operation is the limiting of spawning area for chum salmon below Bonneville Dam.  This may result in redd superimposition, which has been shown to considerably reduce the survival of eggs and fry of early spawners in other salmonids (Hayes 1987; van den Berghe and Gross 1989; Fukushima et al. 1997).  Although some levels of redd superimposition may result in minimal and acceptable mortality, other more severe levels could result in very large losses.  Gravels from adjacent redds may overlap but egg pockets remain undisturbed.  Conversely, multiple redds could be excavated at the same location destroying several successive egg pockets.  In 2005, fishery managers recognized this problem and its role as a limiting factor in chum salmon production, and addressed it by drafting a Systems Operation Request to increase the Bonneville Dam tailwater elevation from 11.5 ft to 13.5 ft.  Their intent was to reduce redd superimposition by providing additional chum spawning habitat in the channel on the north side of Ives Island where spawning was observed in 1998 and 1999 under higher flows.  This SOR was not implemented in 2005 due to a record low escapement, but represents a potential operational solution to reduce redd superimposition and improve the productive capacity of chum salmon spawning areas.  Redd superimposition has been observed at chum salmon spawning locations in the lower Columbia River in 2001, 2002 and 2003, but has not been quantified.  One of the criteria for implementing the 2005 SOR was documenting when, and to what extent, redd superimposition was occurring.  This project will quantify the extent and severity of redd superimposition, in chum salmon spawning areas, document its effects on the productive capacity (i.e., egg to fry survival) of superimposed redds, and test the hypothesis that redd superimposition can be reduced in the Ives Island area and possibly other spawning areas through flow management.

Objectives and rationale:
Objective 1.  Increase the spawning success of mainstem spawning chum salmon by reducing redd superimposition.

Rationale:  Redd superimposition has been documented in chum salmon populations spawning in the lower Columbia River.  The consequence of this is that later spawners may be reducing the egg survival of earlier spawners.  This project will determine the extent to which redd superimposition is occuring at Ives Island and will explore whether it is a function of habitat availability or behavioral choice.  Regardless of the outcome, we will explore the efficacy of altering operations at Bonneville Dam to reduce redd superimposition and thereby improve egg survival and fry production.