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
System-Wide Significance of Predation on Juvenile Salmonids in Columbia and Snake River Reservoirs and Evaluation of Predation Control Measures

BPA project number   9007800

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   Bill Maslen, EWI 503/230-5549

Biological opinion ID   NMFS BO RPA Sec. 14

NWPPC Program number   5.7B.2, 5.7B.5

Short description
In 1990, a study was initiated to estimate the relative magnitude of juvenile salmonid loss to northern squawfish Ptychocheilus oregonensis throughout the Columbia River Basin. To aid effective management, in 1992 a project was initiated to describe squawfish spawning and rearing ecology with the goal of understanding when year-class strength may be determined and the mechanisms underlying recruitment.

Project start year   1990    End year   1997

Start of operation and/or maintenance   

Project development phase   Maintenance

Section 2. Narrative

Related projects

Project history
In 1990, this project was initiated to estimate the relative magnitude of juvenile losses to northern squawfish in reservoirs throughout the Columbia River Basin. In an effort to reduce juvenile salmonid mortality, in 1991 a northern squawfish removal program was initiated in the Columbia and Snake Rivers; a second goal was to evaluate the removal program and to test critical assumptions about mid-reservoir predation processes.

The final goal of the project was to determine mechanisms underlying northern squawfish recruitment and factors affecting year-class strength. During 1993-1995 we monitored densities of northern squawfish larvae and young juveniles in the Columbia River Basin to locate squawfish spawning areas and describe larval and early juvenile rearing habitats. In 1994 we initiated a beach seine study with the objectives of examining growth and mortality of northern squawfish larvae and juveniles in shoreline areas and ascertaining the stage during which year-class strength may be determined. Our primary sampling locations have been areas below Bonneville Dam, the Dalles Pool, the John Day Pool, and two tributaries, the Deschutes and John Day Rivers. We plan for 1996 to be the last year of field work for our study. Sampling will be conducted in the same locations as in 1995, resulting in four years of data in the upper John Day Pool, and two years of data in each of the other sampling locations.

Biological results achieved
Previous project activities have indexed the consumption rate of salmonids by northern squawfish, and characterized diet and consumption rates for other piscivores. The relative abundance of northern squawfish was estimated in reservoirs throughout the basin. Additionally, predation rate and predator density were examined more closely by partitioning reservoirs. When this was done for the John Day Reservoir, estimated numbers of salmonids ingested annually by northern squawfish decreased from 2.9 million to 1.4 million.

The diel and vertical distributions of larval northern squawfish at Columbia River sample locations were identified. Variations in larval squawfish abundance in relation to water temperature and discharge were identified along with probable regions of spawning activity based on densities of larvae in icthyoplankton samples and corroboratory evidence provided from a radio telemetry study on patterns of adult squawfish movement and distribution. In addition, we identified and described variations in abundance of larval and juvenile northern squawfish in shoreline rearing habitats. Other findings described the relationship of northern squawfish larvae and juveniles to fish community composition in the lower Columbia and Deschutes rivers.

Annual reports and technical papers
Gadomski, D.M. and Barfoot, C.A. Diel patterns of distribution and abundance of larval fishes in the lower Columbia and Deschutes rivers. (In preparation, for submittal to Transactions of the North American Fisheries Society)

Barfoot, C.A., D.M. Gadomski, J.M. Bayer, and G.T. Schultz. In Press. Early life history of northern squawfish Ptychocheilus oregonensis in the Columbia River. Annual report by the National Biological Service to the Bonneville Power Administration, Portland, OR.

Barfoot, C.A., D.M. Gadomski, A.M. Murphy, and G.T. Schultz. 1994. Reproduction and early life history of northern squawfish Ptychocheilus oregonensis in the Columbia River. pp. 7-40 In Gadomski, D.M. and Poe, T.P. (eds.), System-wide significance of predation on juvenile salmonids in Columbia and Snake River reservoirs and evaluation of predation control measures. Annual report by the National Biological Survey to the Bonneville Power Administration, Portland, OR.

Gadomski, D.M., and C.A. Barfoot. 1994. American Fisheries Society, 18th Annual Larval Fish Conference, New Brunswick, Canada. Composition and distribution of larval fishes in the lower Columbia River basin.

Gadomski, D.M., and C.A. Barfoot. 1993. American Fisheries Society, Annual Meeting, Portland, OR. Larval and YOY juvenile northern squawfish in the lower Columbia River basin: Mainstem vs. tributary densities and distributions.

Gadomski, D.M., A.M. Murphy, and C.A. Barfoot. 1993. Reproduction and early life history of northern squawfish Ptychocheilus oregonensis in the Columbia River. pp. 26-42 In Petersen, J.H. and Poe, T.P. (eds.), System-wide significance of predation on juvenile salmonids in Columbia and Snake River reservoirs. Annual report by the U.S. Fish and Wildlife Service to the Bonneville Power Administration, Portland, OR

Gadomski, D.M., and A.M. Murphy. 1992. Reproduction and early life history of northern squawfish in the Columbia River. pp. 89-100 In Poe, T.P. (ed.), Significance of selective predation and development of prey protection measures for juvenile salmonids in Columbia and Snake River reservoirs. Annual report by the U.S. Fish and Wildlife Service to the Bonneville Power Administration, Portland, OR.

Petersen, J. H. and T. P. Poe. 1992. Approaches to estimating predation losses in a large river system: predation upon juvenile salmonids in the Columbia River. In C. D. Levings and G. A. Hunter (eds.), An account of the workshop on research approaches to predation/competition questions in river fish communities. Canadian Manuscript Report of Fisheries and Aquatic Science 2150:13-18.

Petersen, J. H. 1994. The importance of spatial pattern in estimating predation on juvenile salmonids in the Columbia River. Transactions of the American Fisheries Society 123:924-930.

Poe, T. P., R. S. Shively, and R. A. Tabor. 1994. Ecological consequences of introduced piscivorous fishes in the lower Columbia and Snake rivers. Pages 347-360, in D. J. Stouder, K. Fresh, and R. J. Feller (eds.), Theory and Application in Fish Feeding Ecology. Bell W. Baruch Library and Marine Sciences, No. 18, University of South Carolina Press, Columbia, South Carolina.

Shively, R. S., T. P. Poe, and S. T. Sauter. In press. Feeding response by northern squawfish to a hatchery release of juvenile salmonids in the Clearwater River, Idaho. Transactions of the American Fisheries Society 125.

Tabor, R. A., R. S. Shively, and T. P. Poe. 1993. Predation of juvenile salmonids by smallmouth bass and northern squawfish in the Columbia River near Richland, Washington. North American Journal of Fisheries Management 13: 831-838.

Ward, D. L., J. H. Petersen, and J. J. Loch. 1995. Index of predation on juvenile salmonids by northern squawfish in the lower and middle Columbia River and in the lower Snake River. Transactions of the American Fisheries Society 24:321-334.

Management implications
Evaluation of predation losses of juvenile salmonids migrating through Columbia River reservoirs will aid management efforts to reduce salmonid losses by controlling predator numbers or developing prey protection measures. A more fine-scaled evaluation of predation processes will allow managers to focus on areas where predation control might be most effective.

Determination of factors that influence northern squawfish populations is important for effective management. The effects of annual and interannual changes in physical and biological factors such as temperature, pool-level fluctuations, discharge, or the concurrent abundance of other fish species on recruitment variation of northern squawfish are largely unknown. Additionally, the effects of northern squawfish population restructuring through removal programs on squawfish reproductive success and the subsequent abundance of larval and juvenile northern squawfish are unknown. The knowledge gained from this project will provide information on the potential effects of adaptive management strategies such as changes in reservoir operations or adult squawfish removal on squawfish population dynamics.

Specific measureable objectives
Our objectives are to 1) examine the early life history of northern squawfish in various habitats of the Columbia River basin; and 2) determine mechanisms underlying northern squawfish recruitment and how environmental factors affect year-class strength. We will continue field sampling in 1996; in 1997 we will synthesize and analyze data collections, and publish information in peer-reviewed journals. Specifically, we will describe annual and interannual variations in larval and juvenile squawfish abundances, identify macrohabitats where spawning activities are highest, describe the dispersal of larval northern squawfish to rearing habitats, and characterize patterns of larval and juvenile squawfish distribution in rearing habitats in relation to physical factors.

Testable hypothesis
This study is directed at providing basic descriptive data on northern squawfish early life history and a foundation for future ecological studies which could address specific testable hypotheses.

Underlying assumptions or critical constraints
None

Methods
We sample ichthyoplankton in main-stem (backwater and main channel locations) and tributary habitats with boat-towed plankton nets and drift nets. Shoreline habitats are sampled with a small, hand-towed sled and 15.5 x 1.2 m beach seines with 3.2 mm mesh. Physical variables such as substrate, depth, water velocity, and vegetation are measured or estimated concurrent with sampling. In the laboratory, fish eggs, larvae, and juveniles are sorted and identified to the lowest possible taxon. Statistical analyses will range from ANOVAs to multivariate techniques depending upon the specific questions being addressed for each publication.

Brief schedule of activities
Tasks projected for fiscal year 1997 include processing 1996 samples, synthesizing and analyzing data, and publishing results on the early life history and ecology of northern squawfish in the lower Columbia River and selected tributaries. Additional publications will address larval fish distribution and community composition in the lower Basin. Research results will also be presented at professional meetings and symposiums.

Biological need
With the ongoing concern about northern squawfish predation on juvenile salmonids, it is necessary to understand the basic life history of this species in the Columbia River for effective management. It is particularly important to understand processes during the early life history stages since this is when the strength of a year-class may be established. Although for many fish species, high mortality occurs during egg and early larval periods, survival during the late larval and juvenile stages can also be critical in the establishment of year-class strength. Long-term studies are required to determine mechanisms underlying northern squawfish recruitment and how environmental factors affect year-class strength.

Critical uncertainties
During 1997, the final year of our study, we will summarize research results and present knowledge of the early life history of northern squawfish, a primary predator on juvenile salmonids in the Columbia River. This information is necessary to effectively manage the species since year-class strength may be established during early life stages. Specifically, we will describe annual and interannual variations in larval and juvenile squawfish abundances, identify macrohabitats where spawning activities are highest, describe the dispersal of larval northern squawfish to rearing habitats, and characterize patterns of larval and juvenile squawfish distribution in rearing habitats in relation to physical factors.

Summary of expected outcome
Research results will address gaps in existing knowledge of northern squawfish ecology and provide accessible published information for managers and researchers.

Dependencies/opportunities for cooperation

Risks
No identifiable risks associated with the project.

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 1 - fund

Recommended funding level   $285,000

BPA 1997 authorized budget (approved start-of-year budget)   $285,000