BPA Fish and Wildlife FY 1997 Proposal

Section 1. Administrative
Section 2. Narrative
Section 3. Budget

see CBFWA and BPA funding recommendations

Section 1. Administrative

Title of project
Impact of Exotic Fishes and Macrophytes on Juvenile Salmonids Rearing in Littoral Areas of the John Day Reservoir

BPA project number   5508800

Business name of agency, institution or organization requesting funding
National Biological Service

Sponsor type   WA-Federal Agency

Proposal contact person or principal investigator

BPA technical contact   , EWI

Biological opinion ID   5, 13h, 14

NWPPC Program number   5.7A.3, 5.7B.15, 5.7B.4

Short description
The proliferation of exotic vegetation and fishes in littoral zones of impounded segments of the Columbia River has substantially modified the ecology of shoreline areas. This project will study 1) habitat use by exotic fishes and possible interactions with juvenile salmonids, and 2) patterns of exotic macrophyte distribution and the role of macrophytes in the trophic dynamics of the Columbia River.

Project start year   1997    End year   2001

Start of operation and/or maintenance   0

Project development phase   Implementation

Section 2. Narrative

Related projects
90-078 - Previous work on the composition and distribution of larval and juvenile fishes in nearshore and backwater areas will be used as a background database and to aid project planning.

Project history

Biological results achieved

Annual reports and technical papers

Management implications

Specific measureable objectives
Objectives are to: 1) quantify the abundance and distribution of exotic and native fishes and macrophytes in nearshore habitats, emphasizing the importance of vegetated habitats to fish communities in the John Day Reservoir; 2) identify possible interactions between exotic fishes and juvenile salmonids in littoral areas; 3) determine if the abundance and composition of aquatic macrophytes may be affecting habitat use by juvenile salmonids by altering physicochemical conditions and biotic communities in the John Day Pool; 4) investigate methodologies for delineating patterns of macrophyte occurrence in the John Day Pool; 5) integrate data collections with existing data on depths and substrates in the John Day Pool using a GIS to predict the effects of water level changes on nearshore habitats and fish communities in John Day Pool.

Testable hypothesis
Although the initial phase of the study we are proposing is largely descriptive, these results could then be used to generate hypotheses testable by manipulative experiments:
(Ho) Changes in water-level management will not affect the relative abundance and distribution of aquatic plants and fishes in the John Day Pool.
(Ho) Experimental removal of macrophyte beds will not alter environmental parameters such as temperature and DO or habitat use by fishes in nearshore areas.
(Ho) Juvenile chinook salmon habitat use is unrelated to aquatic macrophyte abundance.

Underlying assumptions or critical constraints
Water levels and macrophyte abundance are representative of past systems operations.

Methods
For the initial phase of the study (quantifying exotic and native fish abundances in vegetated and non-vegetated habitats) electrofishing and seining collections will be made along representative nearshore habitats from April through August. Shoreline areas within main-channel and backwater habitats will be divided into strata based on substrate type, depth, gradient, distance from shore, and vegetation abundance (possibly a categorical rating based on surface area coverage along the transect, e.g. absent, light, moderate, heavy). To describe differences in physicochemical properties of sampled areas we will measure surface and bottom temperature, DO, turbidity, and velocity along the sampling transect. For the second phase, we will explore the possibility of manipulative experiments to test hypotheses. Specifically, we will test the effect macrophyte removal would have on 1) the structure of nearshore fish communities; and 2) physicochemical conditions. In addition, we will explore different alternatives (e.g. aerial photography, Landsat, or ground surveys) for aquatic macrophyte mapping of the John Day Reservoir.

Brief schedule of activities
During 1997 we will conduct a literature review and project planning. Field gear will be designed, constructed, and tested in various shoreline habitat types. If feasible, we will conduct preliminary work towards the first phase of our study -- quantifying exotic and native fish abundances and distributions in vegetated and non-vegetated habitats and describing patterns of macrophyte abundance. During 1998-2000 we will continue the first phase of our study as necessary, and design and implement phase two -- the effects of macrophyte removal on fish communities and physicochemical conditions. In addition, we will explore different alternatives (e.g. aerial photography, Landsat, or ground surveys) for aquatic macrophyte mapping of the John Day Reservoir. In 2001, data from field work will be analyzed, and manuscripts prepared for publication in peer- reviewed journals. Information will also be incorporated into spatially explicit models for use by managers.

Biological need
The transformation of the Columbia River from a riverine environment into a series of low-velocity impoundments by dams has in many areas resulted in altered habitat more suitable for exotic fishes and plants than native species. In particular, the proliferation of exotic vegetation and fishes in littoral areas of the Columbia River may be acting in concert to reduce the suitability of nearshore rearing habitat for juvenile chinook salmon Oncorhynchus tshawytscha, although these relationships have not been studied. Many exotic fish species now abundant in shoreline and backwater areas of the Columbia River (e.g. cyprinids, ictalurids, centrarchids, and percids) may directly prey upon or compete with juvenile salmonids. Introduced aquatic vegetation (primarily Myriophyllum spp.) may play a central role in the trophic dynamics of the Columbia River by changing water circulation patterns, DO, PH, and the temperature of surrounding areas. Macrophyte beds also create structurally complex habitats possibly increasing the abundance and distribution of associated exotic fish species. The possible use of macrophyte beds by juvenile salmonids for rearing habitat has not been investigated. We propose to describe the abundance and distribution of fishes associated with aquatic vegetation in select habitats of the John Day Pool. Additionally, we will explore alternatives for quantifying patterns of macrophyte distribution and abundance in the Pool. We are selecting the John Day Pool as our study location because linking results from the proposed study with previous work may allow us to extrapolate and explore relationships on a larger scale through spatial modeling. This could lead to greater predictive capabilities and allow managers to “visualize” potential changes in abiotic and biotic interactions in the John Day Reservoir prior to changes in system operations.

Critical uncertainties
Understanding habitat use by exotic fishes in the Columbia River and interactions between exotic fishes and juvenile salmonids in littoral areas is necessary to manage exotic fish populations in a manner that positively affects juvenile salmonids. Knowledge of patterns of exotic macrophyte distribution and the use of macrophyte beds as fish habitat would aid management decisions. Knowledge of the dynamics of shoreline areas is particularly critical in understanding the effects of water-level manipulations on salmonid survival.

Summary of expected outcome
Descriptions of exotic and native fish distributions and abundances in vegetated and non-vegetated habitats. Greater knowledge of the dynamics of interactions between exotic fishes and juvenile salmonids in shoreline rearing areas. Patterns of abundance and distribution of aquatic macrophytes and the importance of macrophyte beds to the distribution of juvenile salmonids. Knowledge of the effect of macrophyte removal on the structure of fish communities. Reports and publications to aid managers in decisions concerning actions affecting critical shoreline habitat. For example, our study would provide information on how water level manipulations could affect fishes and plants in littoral areas. Information could be incorporated into spatially explicit models to allow managers to “visualize” potential changes in abiotic and biotic interactions in the John Day Reservoir prior to changes in system operations.

Dependencies/opportunities for cooperation

Risks
Possible effects of electroshock on juvenile salmonids will be explored. If this method is not feasible, we will investigate various netting systems.

Monitoring activity
Annual reports, presentations at meetings, publications in peer-reviewed journals.

Section 3. Budget

* For most projects, Authorized is the amount recommended by CBFWA and the Council. Planned is amount currently allocated. Contracted is the amount obligated to date of printout.

Funding recommendations

CBFWA funding review group   System Policy

Recommendation    Tier 3 - do not fund