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
An Ecosystem-Based Strategy to Identify Critical Links Affecting Juvenile Salmon Growth and Survival in Columbia River Reservoirs

BPA project number   5509400

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   10.7, 5.5A, 5.7, 5.7A.2

Short description
Impoundment, system operations, and exotic species may directly or indirectly affect juvenile salmon growth and survival. Studies will examine links between existing and potential microhabitats, primary production, macrophytes, exotic fish, predators, and juvenile salmon, thus improving predictions about juvenile salmon in this complex ecosystem.

Project start year   1997    End year   

Start of operation and/or maintenance   0

Project development phase   Implementation

Section 2. Narrative

Related projects
Since this project would investigate many different links in the reservoir food web, numerous past and ongoing studies funded by BPA, COE, and others would be useful. Some of the most relevant studies are:
-- BPA 8200300 and 9007800 - Predation studies - Extensive data are available for modeling and evaluating the relative importance of predators upon juvenile salmon. Predation studies (supported by BPA) by the Oregon Department of Wildlife and other agencies also provide data and analyses.
-- BPA 8605000 - White sturgeon studies - the spatial data developed in that study will be used to partially populate the geographic information system.
-- BPA 9102900 - Fall chinook salmon studies - This work provides data on nearshore and offshore distributions of fall chinook salmon relative to water velocities.
-- NMFS limnology study, funded by COE. Data on water quality and benthic conditions.
-- NBS nearshore fish habitat study, funded by COE (1995). Data on nearshore fish communities in John Day Reservoir.

Project history
N/a

Biological results achieved
N/A

Annual reports and technical papers
N/A

Management implications
N/A

Specific measureable objectives
Identify species, habitats, and processes (“critical links”) in Columbia River reservoirs that cause a disproportionate change in salmon growth or survival. By identifying and quantifying these critical links a new framework will be established for evaluating both the direct and indirect impacts of management’s actions.

Testable hypothesis
General hypothesis:
Certain habitats, species, or processes within the reservoirs are not more critical to the maintenance of the ecosystem than others, and change in these critical links will not cause cascading effects on other trophic levels, particularly juvenile salmon.

Specific hypotheses ( examples):
- Hydropower system operations (e.g., water level manipulations) have no effect on primary and secondary production in the system.
- Juvenile salmon growth and survival are not related to changes in primary and secondary production.
- Changes in hydropower system operations will not affect the abundance or distribution of critical aquatic habitats, which in turn may limit populations of resident and anadromous exotic fishes.
- Juvenile chinook salmon growth and survival are not related to the abundance or density of exotic fishes and aquatic macrophytes.

Underlying assumptions or critical constraints
-- Critical links in reservoir food webs relevant to juvenile salmon have been correctly identified (see Figure on page 6 and discussion in the Biological Needs section).
-- System operations during the study will provide conditions that will enable us to draw inferences about responses to future system operations.
-- Management activities specified in the Biological Opinion are capable of inducing changes in juvenile salmon growth and survival.

Methods
Methods are summarized for four major components of the project. See the section on Biological Needs for justification and description of these components.

Primary and secondary production
The magnitude and pathways of energy flow through the trophic structures of the reservoirs vary spatially and temporally. Representative areas, e.g. nearshore and pelagic, will be sampled for physical parameters (temperature, DO, conductivity, water transparency) and major nutrients (nitrogen and phosphorus species, silica, TOC). Biomass of lower trophic levels will be estimated directly: algal biomass will be estimated using chlorophyll a concentration and algal counts; bacterial biomass will be estimated using the Acridine Orange epiflourescence technique; zooplankton will be enumerated microscopically and lengths measured (for calculation of biomass). In addition, rates of production for these communities will be measured. Algal primary productivity will be estimated using the C-14 technique. Bacterial productivity will be estimated using H3-Thymidine incorporation rates. Zooplankton grazing rates will be estimated using a Haney chamber, which measures in situ community grazing on algae and bacteria. These data can be used to estimate the carrying capacity of the reservoirs for higher trophic levels.

Macrophytes and resident exotic fishes
For the initial phase of the study (quantifying exotic and native fish abundances in vegetated and non-vegetated habitats) electrofishing and/or 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, 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 density would have on 1) the structure of nearshore fish communities; and 2) physicochemical conditions of nearshore areas. In addition, we will explore different alternatives (e.g., aerial photography, Landsat, or ground surveys) for aquatic macrophyte mapping of the John Day Reservoir.



American shad studies
American shad, an anadromous exotic fish, have several critical links in Columbia River reservoirs, particularly to juvenile fall chinook salmon. American shad eggs and larvae will be sampled biweekly using 0.5 m2 plankton nets (500 mm mesh). Late summer indices of juvenile abundance will be estimated using beach seines in shallow nearshore habitats and a hydroacoustic fish stock assessment system in limnetic areas. To determine if juvenile shad are a prey and/or competitor with juvenile fall chinook salmon we will assess spatial and temporal distribution patterns and diet overlap. These data will be used in a bioenergetics model to assess potential interactions. The contribution of juvenile American shad to seasonal growth and fecundity of predators will be estimated using techniques developed by Oregon Department of Fish and Wildlife and the National Biological Service during predation studies. Statistical analyses will include correlative approaches for exploring relationships between shad densities and other variables and ANOVAs for between or among habitat or year differences in shad densities.

Modeling and Integration
Models will be used as tools to account for the diversity of processes operating across trophic levels and at different scales within the river ecosystem. Several different types of models will be used since a single model cannot accommodate all spatial and temporal scales, nor can a single model accurately describe processes that occur across several trophic levels. Physical data will be summarized and response variables computed with cartographic modeling in a GIS (ARC/INFO, EPPL7, or others). The feeding response of predators on juvenile salmon has been studied with individual-based models, which allow movement and behavior of both predators and prey in a spatially variable environment. Primary production can be modeled with relatively simple process models that describe biomass production, consumption, and decomposition by several functional groups of biota. To integrate these models we will collaborate with groups that have already made advances in modeling complex ecosystems. For example, several agencies are collaborating to study and model the South Florida ecosystem and they have developed an approach to predict system response across spatial scales and trophic levels.

Brief schedule of activities
1997 general tasks:
-- Input available spatial data describing bathymetry, water surface elevation models, substrates, fish habitats, etc. into a GIS; identify additional data and hardware needs. Develop methods to predict changes in abiotic variables to system operation changes.
-- Conduct pilot studies to design and develop experimental protocols on primary production, macrophytes, etc..
-- Review approaches and technologies available for modeling ecosystems (e.g., South Florida Ecosystem Model - NBS/National Park Service, Long-Term Resource Monitoring Program on the Upper Mississippi - NBS/COE).

1998-2001 general tasks:
-- Specific field and laboratory studies to quantify relations between habitat and food web components.
-- Refine the modeling approaches and conduct experiments.
-- Presentation and publication of results.

Biological need
Human activities in the Columbia River Basin have caused a complex sequence of abiotic and biotic changes in the river ecosystem. Dam construction and impoundment have altered the physical morphometry and thermal regimes of the rivers, while daily system operations change the water velocity and water levels in a reservoir. The effects of wind, temperature, and solar radiation have been altered, along with the substrate, water chemistry, turbidity, and other factors. Compared to historical conditions, native plants and animals thus live in a highly modified environment. In addition to these physical changes, numerous species of plants, invertebrates, and fishes have been introduced into the system (“exotic” species), further disrupting the historic community structure by modifying microhabitats and changing trophic relationships.

These modified physical conditions and exotic species cause both direct and indirect impacts on juvenile salmon (Figure). System operations that change water levels in the reservoirs (drawdown, power peaking, etc.), for example, likely influence primary productio, macroinvertebrates, and macrophyte beds, which in turn may regulate exotic fish populations. Exotic macrophytes such as watermilfoil provide enhanced rearing habitats for smallmouth bass and other centrarchids, and these species may prey upon or compete with juvenile salmon. Juvenile American shad are abundant in late summer and early fall and may be competing with outmigrating juvenile salmon, especially endangered Snake River stocks of fall chinook salmon. These changes often occur in specific parts of the river system (nearshore zones with high primary productivity, macrophyte beds, etc.), but their impacts may extend to whole populations or to system attributes (salmonid survival, system productivity, etc.). By understanding the mechanisms and links in the river community, we will be better able to predict how untested management options influence juvenile salmon growth and survival, especially those actions that cause significant changes in other trophic levels. Without a basic understanding of the quantitative effects of these critical links, predictions about species in this complex system will be impossible.

Critical uncertainties
Management decisions and system operations are often based on point-to-point survival estimates (coded-wire tag, PIT tag) or salmonid mortality estimates during dam passage. Except for predation, relatively little is known about the mechanisms that influence juvenile salmonid growth and survival within these large reservoirs, although mortality in the reservoir pool has been estimated to be equal to, or higher than, dam-related mortality. Reservoir pools are generally assumed to be homogeneous in passage models, but available data indicate that large reservoirs are heterogeneous in their physical, chemical, and biological components. This heterogeneity has profound effects on the production and structure of the reservoir community. Within this diverse reservoir landscape, we need to understand the direct and indirect mechanisms that affect juvenile salmon to be able to predict how local or regional management actions cascade across trophic levels and extend across broad areas.

Summary of expected outcome
-- Longitudinal and cross-river estimates of primary and secondary production related to lower Columbia River system operations.
-- An understanding of how exotic fish and macrophytes influence predation (or competition) on juvenile salmon in reservoirs.
-- The role of juvenile American shad as a competitor with juvenile salmon and as an important energy source for northern squawfish during autumn.
-- Spatial and trophic models that could lead to greater predictive capabilities, allowing managers to visualize potential changes to the biotic and abiotic environment prior to altering hydropower system operations.

Dependencies/opportunities for cooperation
Collecting permits and permissions would be obtained from the appropriate state and federal agencies.

Collaborators:
-- Oregon Department of Fish & Wildlife will examine the role of American shad in the diet and condition of northern squawfish.
-- Dr. Ralph Vaga (Portland State University) will estimate primary and secondary production.
-- Dr. Don DeAngelis (South Florida Ecosystem Research Team) will collaborate in model development and application.

Opportunities for cooperation:
-- Opportunities exist to cooperate with water managers (BPA, COE, DEQ) to assess management actions during the next 5 years. These may include small water level manipulations to test hypotheses about the impacts of major management actions.
-- Opportunities to cooperate with fisheries management agencies and tribes who are studying juvenile salmon survival (NMFS, USFWS), predation (ODFW, CRITFC, USFWS) and hatchery versus wild interactions (WDFW, ODFW, IDFG, NBS).

Risks
This work poses minimal risk to the public welfare and governmental and tribal interests.
This work will not jeopardize salmon stocks.

Monitoring activity
Progress will be reported in annual reports, oral presentations, and in peer-reviewed journal articles.

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 2 - fund when funds available

Recommended funding level   $575,000