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
Distribution of Juvenile Salmonid Populations and Total Dissolved Gas Supersaturation in Reservoirs

BPA project number   9603100

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   NMFS BO 2, 16

NWPPC Program number   

Short description
We propose to use a hydroacoustics fish stock assessment system to assess the vertical distribution of juvenile salmonids as they pass through areas of total dissolved gas supersaturation (TDGS). The prevelance of gas bubble trauma symptoms in juvenile salmonids will be assessed in another closely related study by Backman et al. (CRITFC). We also propose to monitor spatial and temporal patterns of TDGS levels throughout the study area. Using data from the first year, we will design and conduct a multi-factor field experiment including fish distribution, assessment of gas bubble trama symptoms in fish and TDGS levels.

Project start year   1997    End year   2001

Start of operation and/or maintenance   0

Project development phase   Implementation

Section 2. Narrative

Related projects
“Vertical and horizontal distribution of individual juvenile steelhead based on radiotelemetry for gas monitoring” (Beeman and Maule, NBS). They propose to use a depth sensitive radio tag in juvenile salmonids to determine individual exposure history of fish migrating through reservoirs with areas of high and low TDGS.

“Gas bubble trauma symptoms of salmon smolts in the Snake and Columbia rivers” (Backman et al., CRITFC). Field experiments proposed in this study will be conducted with Beeman and Maule and Backman et al. thereby providing fish population distribution, TDGS distribution, exposure history of individual juvenile salmonids, and occurrence of gas bubble trauma symptom in juvenile salmonids in reservoirs.

Smolt Monitoring Program: provides data on occurrence of gas bubble trauma symptoms at dams.

Project history

Biological results achieved

Annual reports and technical papers

Management implications
The fish distribution information will provide managers with a measure of the portion of the population of juvenile salmonids migrating below the depth of compensation for gas supersaturation levels and the portion of the population migrating above the depth of compensation. We believe fish distributions described using hydroacoustics will be representative of the population and can be used to assess exposure history of juvenile salmonids as determined by depth sensing radio tags and the occurrence gas bubble trauma symptoms in a subsample of the population. This in turn will be helpful in assessing the risk of gas supersaturation within a given reach when spill at individual dams could reduce mortality compared to turbine passage. Because this issue is controversial, we believe managers will want to examine the results and then infer the risks or benefits of certain flow and spill alternatives.

Specific measureable objectives
Phase I:
1) Develop and test alternative hydroacoustic transducer deployment methods that offer optimum resolution in assessing near-surface fish distributions.
2) Develop and test a gas monitoring bouy to track and monitor plumes of gas supersaturated water masses within the study site when experiments are conducted.
Phase II:
3) Using a multi-factor experiment in a reservoir, determine the occurrence of gas bubble trauma symptoms as it relates to TDGS, spill, flow, and juvenile salmonid behavior.

Testable hypothesis
1) Juvenile salmonids are distributed spatially and temporally uniformly above and below the depth of compensation during periods of TDGS.

2) Juvenile salmonids are distributed spatially and temporally uniformly in gas plumes in reservoirs.

3) Denisty of juvenile salmonids does not change in response to high and low TDGS levels.

Underlying assumptions or critical constraints
1) TDGS levels greater than 100% will occur during spring emigration.
2) We will be able to improve precision and accuracy of estimates of near-surface fish distributions.

Methods
1) Experimental design: Fish distribution will be assessed using a mobile hydroacoustic survey system deployed from a boat. During the first year we will test several alternative deployments of hydroacoustic transducers to determine the best method to determine near-surface fish distributions. This is an important issue because the fish above the depth of compensation, usually <1-4 m, are at greater risk to TDGS levels. The survey boat will be equipped with a global positioning system (GPS) to determine boat position. An acoustic Doppler current profiler will be used to measure water velocity throughout the study area. Data will be collected along transects located using GPS waypoints.

To track and monitor supersaturation levels, we propose to use instrumented buoys equipped with recording TDGS meters, recording GPS units, and radio telemetry to relocate bouys. This method will allow tracking masses of water with high or low levels of TDGS with a minimal amount of effort. We will collect fish distribution and TDGS data during periods of spill and non-spill throughout the spring smolt emigration period (April 1 - June 15).

2) Statistical analysis: Data will be analyzed by echo counting techniques using proprietary software. Density of fish in 1 m strata of the water column will be estimated by dividing the echo count by the volume of water sampled by the hydroacoustic system. Hydroacoustic data and TDGS levels will be analyzed using various statistical methods. A statistician will be consulted after preliminary data is collected to assist in adjustments to design and allocation of effort. Final design based on the first year of data will be reported at end of first year.

3) Number of fish: No fish will be required for these activities. Species verification will be made using the species composition from fish collected by Backman et al. to determine the occurrence of gas bubble trauma. The reduced need to handle fish when estimating fish distributions with a hydroacoustic system is one of the advantages of this approach.

Brief schedule of activities
1997: Develop an improved method of hydroacoustic transducer deployment and gas plume tracking methods.

1998-2000: Collect hydroacoustic data, TDGS data, and occurrence of gas bubble trauma symptoms in cooperation with Backman et al., analyze data, and report results on an annual basis.

2001: Prepare final report for BPA and articles for publication in peer-reviewed journals.

Biological need
The magnitude of the impact of TDGS levels above 110% on the survival of juvenile salmonids in the river remains controversial. Hydrosystem operators, fishery managers, and fishery researchers wish to define this relation more precisely. Ultimately, studies will be necessary to measure exposures of fish in reservoirs to TDGS and assess the occurrence of gas bubble trauma symptoms. We believe that hydroacoustic data on fish distribution will support the critical step when inferences about smolt populations are made based on observed occurrence of gas bubble trauma symptoms.

Critical uncertainties
1) The number or portion of the population of juvenile salmonids distributed above the depth of compensation during various levels of TDGS in unknown. Without knowledge of the distribution or the occurrence of gas bubble trauma symptoms it is difficult to complete a risk assessment of TDGS levels above 110% in reservoirs.

2) Testing and deployment of transducers to better assess near-surface distribution will need to be successful before we can accomplish our objectives.

Summary of expected outcome
We expect to collect sufficient data on juvenile salmonid vertical distribution and TDGS. Findings from this data will advance the understanding of the relations between fish distribution, TDGS, and gas bubble trauma symptoms. Ultimately, this will provide fishery managers, hydrosystem operators, and researchers with the much needed tools to address the risks and benefits associated with a range of spill levels.

Dependencies/opportunities for cooperation
Collaborators:
Dr. Thomas W. H. Backman, Columbia River Inter-Tribal Fish Commission, Portland.

Opportunities for cooperation:
Fish Passage Center, Smolt Monitoring Program, staff monitor occurrence of gas bubble trauma symptoms at dams and conduct quality control that will be coordinated with Backman et al.

U.S. Army Corps of Engineers operates a series gas monitoring sites and we will cooperate with them to use inseason results.

Risks
Operating boats on the Columbia and Snake rivers present some minimal safety concerns, but staff of the Contractor are very experienced.
This work poses no known risk to the public, government agencies, or Indian tribes.

Hydroacoustic sampling is a nonlethal approach to assess fish distribution and therefore this project will have no deleterious effect on endangered salmon stocks.

Monitoring activity
Progress will be reported in annual progress reports, presentations at professional meetings, presentations to fisheries agencies and tribes, 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   $552,000