BPA Fish and Wildlife FY 1998 Proposal

Section 1. Summary
Section 2. Goals
Section 3. Background
Section 4. Purpose and methods
Section 5. Planned activities
Section 6. Outcomes, monitoring and evaluation
Section 7. Relationships
Section 8. Costs and FTE

see CBFWA and BPA funding recommendations

Section 1. Summary

Title of project
GBD: Changes in Signs/Effects on Survival

BPA project number   9602400

Short description
PIT-tagged run-of-the-river hatchery fish will be exposed to water containing supersaturated dissolved atmospheric gasses, examined for signs of GBD, and released into the forebay of Little Goose Dam. A percentage of these fish will be recaptured at the Little Goose Dam collection facility and reexamined to determine changes in GBD signs attributable to increased hydrostatic pressure during passage into the juvenile salmon bypass system. Treatment and control groups will be interrogated at PIT-tag detector systems at downstream dams to evaluate survival differences.

Business name of agency, institution or organization requesting funding
National Marine Fisheries Service, Coastal Zone and Estuarine Studies Division

Proposal contact person or principal investigator

Section 2. Goals

General
Supports a healthy Columbia basin; adaptive management (research or M&E)

Section 3. Background

Stream area affected

Subbasin   Lower Snake and Columbia River

History
The NMFS Gas Bubble Disease Research Priorities document identifies this research approach as one method for evaluating two critical uncertainties: 1) Do GBD sampling protocols for juvenile salmonids at dams produce data which properly represent fish populations in the river? 2) Does prevalence and severity of GBD at the sampling sites indicate mortality from GBD occurring upstream from the monitoring sites.

Biological results achieved
Data obtained in 1996 identified a decrease in prevalence and severity of GBD signs in steelhead released 0.5 km upstream from the dam. A smaller decrease in prevalence and severity was observed in fish held in a 5-m deep net-pen.

No statistical difference in survival was observed for GBD-challenged steelhead compared with unchallenged counterparts, either at passage through Little Goose Dam or at passage through the other dams downstream.

Additional tests are necessary to separate the effects of hydrostatic pressure during dam passage from the effects of the depth distribution during reservoir residence on GBD signs. Faster recovery of fish passing through the dam will be necessary.

Because fish size may be of significant importance in rate of predation, smaller juvenile salmon must be used in a similar GBD challenge test to confirm that survival is not decreased. Exclusive use of juvenile steelhead for these tests may have resulted in a conservative estimate for decreases in survival associated with GBD effects during migration. Recent results from laboratory tests of juvenile salmon suggested higher predation by northern squawfish for fish exposed to dissolved gas supersaturation than for unexposed cohorts (Matthew Mesa, National Biological Service, Cook, WA., pers. commun.) However, compared with juvenile salmon migrants, the greater size and speed of steelhead likely decreases predation by fish and birds..

Project reports and papers
Annual report in preparation.

Adaptive management implications
Potential changes in signs of GBD that may result from fish passing through juvenile bypasses (pressure effects) raises concerns regarding the representativeness of fish sampling at dams for GBD evaluation. Resolving this question is critical to ensure information used for river operations management is adequate for addressing potential risks associated with DGS and GBD. Similarly, improved understanding of the effects of GBD on survival will allow better informed operational decision-making in managing spill and choosing fish passage pathways.

Section 4. Purpose and methods

Specific measureable objectives
We will measure changes in signs of GBD (external subcutaneous emphysema) in juvenile salmonids as they migrate through a bypass/collection facility at Little Goose Dam. Such changes could be induced by the sounding required by the fish to enter the gatewells before migrating through the rest of the system. We will also measure relative survival of juvenile salmonids allowed to migrate after exposure to levels of supersaturated atmospheric gases that induced signs of GBD in about 50% of the population.

Critical uncertainties
The juvenile steelhead used in the tests represent a portion of the downstream migrating salmonid population, and their larger size and behavioral differences from chinook and sockeye salmon may have produced results that are indicative for steelhead only. Experimental exposure may not impact test fish in the same manner that river-run fish are impacted by GBD; results, therefore, may not be representative. Risks to non-target previously PIT-tagged fish by excessive handling are minimized through installation of a separation-by-code diverter at Little Goose Dam.

Biological need
This study has been designed to answer 1) if migrating juvenile salmonids lose signs of GBD while passing through a bypass/collection facility, and 2) if fish exposed to supersaturated dissolved gasses die in the reservoir before reaching bypass/collection facilities. Answers to these questions will help determine the usefulness of monitoring sites at dams in detecting signs of GBD in migrating salmonids and identifying potential mortality upstream from the monitoring site.

Hypothesis to be tested
Hypothesis 1: Juvenile salmonids with signs of GBD do not lose these signs by passage through a gatewell into bypass systems at dams on the Snake or Columbia Rivers. Hypothesis 2: An increase in mortality of juvenile salmonids with GBD does not affect the ability to detect signs of GBD at bypass/collection facilities on the Snake or Columbia Rivers.

Alternative approaches
Other approaches are being conducted--survival assessments using PIT-tag interrogations at dams, and riverine sampling for GBD in juvenile salmon to compare with data from samples at dams. Because each approach has inherent problems, we need to conduct all of the studies to resolve the questions.

Justification for planning
The potential for unidentified mortality from effects of GBD is unacceptable.

Methods
To provide enough fish for a statistically valid assessment of changes in GBD signs during dam passage, 6 replicate releases of 300 test fish will be made for each of the 3 test series (yearling chinook salmon and steelhead). Similar sized groups of control fish will be released and 150-fish groups exposed to supersaturation will be retained in 5-m net-pens in the forebay. Test and control groups will be anesthetized and PIT tagged. Fish groups will be placed into separate but identical holding tanks with degassed river water at densities less than 60 g/L (0.50 lb/gal.). The dissolved gas levels in the test fish tank will be increased to and held at about 120% of saturation using a bubbleless membrane aeration system installed in the water line. Both control and test fish will be held an additional 1 to 2 days until about 50% of the test fish display signs of GBD.
For each test replicate, when prevalence of GBD signs reaches 50% or mortality begins, test fish will be extracted (in small groups), anesthetized, and visually examined at 5- to 20-power magnification for subcutaneous emphysema and emboli in lateral line scale pockets. Severity of emphysema will be assessed as percentage of body area affected and relative size and shape of emboli. Coincidentally, control fish will be extracted, anesthetized, and a subsample examined for GBD, while others will be held out of the water for approximately the time required for GBD examination. After examination, half the test and control fish will be placed in a common tank, transported, and released about 400 m upstream from the Little Goose Dam powerhouse. Since the examination process will take an extended period of time, multiple releases will be made. We plan to make the releases near dusk to facilitate rapid passage through the dam and bypass system. The other half will be released directly in front of the operating turbine to facilitate rapid passage.
Signs of GBD among test fish may be changing during the period prior to passage through the dam. Therefore, a third group of PIT-tagged fish from the supersaturated test condition will be examined and then placed in a forebay net-pen (5-m deep) to allow documentation of changes in GBD signs through time at ambient dissolved gas concentrations in Little Goose Dam forebay.
Using a mechanical gate to separate PIT tags by code, test and control fish will be automatically separated from other fish passing through the bypass system at Little Goose Dam and examined immediately to determine any changes in the prevalence and severity of GBD signs. Interrogation of PIT-tagged test and control fish at Little Goose, Lower Monumental, Ice Harbor, and McNary Dams will provide an estimate of differential survival during migration.
Approximately 5,000 hatchery fish will be needed for each test series. Possible fish sources include: 1) Marked hatchery steelhead could be sorted from the Little Goose or Lower Granite Dam collection system. 2) Yearling chinook salmon from Lookingglass, Lyons Ferry, or Kooskia Hatcheries.

Section 5. Planned activities

Constraints or factors that may cause schedule or budget changes
Lack of test fish availability may cause changes in the scope of the tests. The only known risk is the inadvertent handling of in-river migrants which are PIT tagged as part of other up river projects. With installation and preliminary testing of a rotating gate at Little Goose Dam, separation by code appears to be about 95% efficient--as seen at Lower Granite Dam during testing and in use as part of a subyearling study (Sandra Downing, NMFS, Manchester, WA, pers. comm.) .

Section 6. Outcomes, monitoring and evaluation

SUMMARY OF EXPECTED OUTCOMES

Expected performance of target population or quality change in land area affected
All data shall be analyzed by the December 1998. This will produce a database which should help answer questions to the critical uncertainties mentioned above.

Present utilization and convservation potential of target population or area
Normal production

Assumed historic status of utilization and conservation potential
N/A

Long term expected utilization and conservation potential for target population or habitat
N/A

Contribution toward long-term goal
Validation of GBD sampling data at dams and knowledge of survival related to GBD.

Indirect biological or environmental changes
None.

Physical products
5,000 PIT-tagged chinook salmon and steelhead.

Environmental attributes affected by the project
N/A

Changes assumed or expected for affected environmental attributes
N/A

Measure of attribute changes
N/A

Assessment of effects on project outcomes of critical uncertainty
Examination of non-target fish percentages will allow adjustment of the PIT-tag selector gate to accommodate a low rate of error.

Information products
Percentages of GBD signs loss and change, and diminished survival from GBD impacts to juvenile salmonids during migration.

Coordination outcomes
FPC and BRD will utilize results to reevaluate efficacy of current GBD monitoring protocols for juvenile salmonids.

MONITORING APPROACH
(See Methods section)

Provisions to monitor population status or habitat quality
N/A

Data analysis and evaluation
Statistical analysis using ANOVA.

Information feed back to management decisions
If based on results of these tests, it is apparent that the assessment error rate (signs change) is a high percentage and/or survival is decreased, and other studies by CRITFC, Cramer, and NMFS (identified earlier) corroborate these findings, then steps must be taken to obtain more representative samples for regional GBD assessment.

Critical uncertainties affecting project's outcomes
Based on results from 1996, non-target fish captures appear to be within acceptable ranges for continuing research. Lack of appropriate test fish will delay conduct of this research.

Evaluation
Results to be evaluated will be observed changes in signs and survival and the precision of those measurements.

Incorporating new information regarding uncertainties
Through discussions with investigators and the contracting officers technical representative.

Increasing public awareness of F&W activities
Dissemination of results via written reports, publications, presentations at meetings.

Section 7. Relationships

Section 8. Costs and FTE

1997 Planned  $228,000

Other non-financial supporters
N/A

How does percentage apply to direct costs
total direct labor charges only.