DEVELOPMENT OF A SYSTEM-WIDE PREDATOR CONTROL PROGRAM: STEPWISE IMPLEMENTATION OF A PREDATION INDEX, PREDATOR CONTROL FISHERIES, AND EVALUATION PLAN IN THE COLUMBIA RIVER BASIN Annual Report 1993 VOLUME I - IMPLEMENTATION Prepared by: Charles F. Willis S. P. Cramer and Associates, Inc. David L. Ward Oregon Department of Fish and Wildlife Cooperators: Oregon Department of Fish and Wildlife S. P. Cramer and Associates, Inc. Washington Department of Wildlife Columbia River Inter-Tribal Fish Commission University of Washington National Marine Fisheries Service Pacific States Marine Fisheries Commission Oregon State University Prepared for: U. S. Department of Energy Bonneville Power Administration Environment, Fish and Wildlife Division PO Box 3621 Portland, Oregon 97208-3621 Project Number: 90-077 Contract Number: DE-BI79-90BP07084 June 1995 DEVELOPMENT OF A SYSTEM-WIDE PREDATOR CONTROL PROGRAM: STEPWISE IMPLEMENTATION OF A PREDATION INDEX, PREDATOR CONTROL FISHERIES, AND EVALUATION PLAN IN THE COLUMBIA RIVER BASIN Annual Report 1993 VOLUME II - EVALUATION Prepared by: Charles F. Willis S. P. Cramer and Associates, Inc. David L. Ward Oregon Department of Fish and Wildlife Cooperators: Oregon Department of Fish and Wildlife S. P. Cramer and Associates, Inc. Washington Department of Wildlife Columbia River Inter-Tribal Fish Commission University of Washington National Marine Fisheries Service Pacific States Marine Fisheries Commission Oregon State University Prepared for: U. S. Department of Energy Bonneville Power Administration Environment, Fish and Wildlife Division PO Box 3621 Portland, Oregon 97208-3621 Project Number: 90-077 Contract Number: DE-BI79-90BP07084 June 1995 CONTENTS Page VOLUME I. IMPLEMENTATION . 1 EXECUTIVE SUMMARY by Charles F. Willis . :-. 2 REPORT A. Implementation of a Floating Trap-Net Fishery for Northern Squawfish in the Columbia River Downstream from McNary Dam by Christine Mallette, Thomas K. Iverson, Brian D. Mahoney, andStephen B. Mathews . 11 REPORT B. Evaluation of the Northern Squawfish Sport-Reward Fishery in the Columbia and Snake Rivers by Daniel C. Klaybor, Craig C. Burley, Scott S. Smith, Eric N. Mattson, Eric C. Win&r, Paul E. DuCommun, Heather R. Bartlett, and Stacie L. Kelsey . 63 REPORT C. Northern Squawfish Sport-Reward Payments by Russell G. Porter . ...155 REPORT D. Controlled Angling for Northern Squawfish at Selected Dams on the Columbia and Snake Rivers and Diet Analysis of Incidentally Caught Channel Catfish by the Colzunbia River Inter-Tribal Fish Commission . , . 163 REPORT E. Removal of Predacious Northern Squawfish Found Near Hatchery Release Sites in Bonneville Pool: An Analysis of Changes in Catch Rates and Diet Associated with the Release of Hatchery-Reared Juvenile Salmonids by Ken Collis, Roy E. Beaty, Becky Ashe, George Lee, Blaine Parker, and Kathy McRae . ...221 REPORT F. Investigation of Northern Squawfish Concentrations in Tributaries to the Mainstem Columbia, Snake and Clearwater Rivers by Becky Ashe, Roy E. Beaty, and Manuel P. Villalobos . .263 REPORT G. Effectiveness of Predator Removal for Protecting Juvenile Fall Chinook Salmon Released from Bonneville Hatchery by Richard D. Ledgerwood, Earl M. Dawley, Lyle G. Gilbreath, Margaret A. Toner, Thomas P. Poe, and Harold L. Hansen . 303 i Page VOLUME II. EVALUATION EXECUTIVE SUMMARY by David L. Ward . 353 REPORT H. Development of a Systemwide Predator Control Program: Indexing and Fisheries Evaluation by Mark P. Zimmerman, - Chris Knutsen, David L. Ward, and Kent Anderson . 357 REPORT I. Economic, Social, and Legal Feasibility of the 1993 Northern Squawfish Removal Fisheries and Fish Distribution System by Susan HannaandJonPampush. ..431 ii VOLUME I. IMPLEMENTATION Cooperators Oregon Department of Fish and Wildlife Columbia River Coordination Section S.P. Cramer and Associates, Inc. Washington Department of Wildlife Pacific States Marine Fisheries Commission Columbia River Inter-Tribal Fish Commission University of Washington National Marine Fisheries Service EXECUTIVE SUMMARY by Charles F. Willis We report our results from the third year of a basinwide program to harvest northern squawfish (Ptychocheilw oregonensis) in an effort to reduce mortality due to northern squawfish predation on juvenile salmonids during their emigration from natal streams to the ocean. Earlier work in the Columbia River Basin suggested predation by northern squawfish on juvenile salmonids may account for most of the lo-20% mortality juvenile salmonids experience in each of eight Columbia and Snake River reservoirs. Modeling simulations based on work in the John Day Reservoir from 1982 through 1988 indicated it is not necessary to eradicate northern squawfish to substantially reduce predation-caused mortality of juvenile salmonids. Instead, if northern squawfish were exploited at a rate of lo-20%) reductions in numbers of larger, older fish resulting in restructuring of their population could reduce their predation on juvenile salmonids by 50% or more. Consequently, we designed and tested a sport-reward angling fishery and a commercial longline fishery in the John Day pool in 1990. We also conducted an angling fishery in areas inaccessible to the public at four dams on the mainstem Columbia River and at Ice Harbor Dam on the Snake River. Based on the success of these limited efforts, we implemented three test fisheries on a multi-pool, or systemwide, scale in 1991 - a tribal longline fishery above Bonneville Dam, a sport-reward fishery, and a dam-angling fishery. Low catch of target fish and high cost of implementation resulted in discontinuation of the tribal longline fishery. However, the sport-reward and dam-angling fisheries were continued in 1992 and 1993. In 1992, we investigated the feasibility of implementing a commercial longline fishery in the Columbia River below Bonneville Dam and found that implementation of this fishery was also infeasible. Although we were unable to implement an effective longline fishery, it was important to the attainment of program objectives to attempt to substantially increase total annual exploitation. Estimates of combined annual exploitation rates resulting from the sport-reward and dam-angling fisheries remained at the low end of our target range of lo-20%. This suggested the need for additional, effective harvest techniques. During 1991 and 1992, we developed and tested a modified (small-sized) Merwin trap net. We found this floating trap net to be very effective at catching northern squawfish at specific sites. Consequently, in 1993 we examined a systemwide fishery using floating trap nets. Evaluation of the success of test fisheries in achieving our target goal of a lo-20% annual exploitation rate on northern squawfish, together with information regarding the economic, social, and legal feasibility of sustaining each fishery, is presented in Section II of this report. The implementation team consisted of the Oregon Department of Fish and Wildlife (ODFW), S.P. Cramer and Associates, Inc. (SPCA), the Washington Department of Wildlife 2 (WDW), the Columbia River Inter-Tribal Fish Commission (CRITFC), the University of Washington (VW), the National Marine Fisheries Service (NMFS), and the Pacific States Marine Fisheries Commission (PSMFC). ODFW, with assistance from SPCA, was responsible for coordination and administration of the entire program and subcontracted various tasks and activities to WDW, CRITFC, UW, NMFS, and PSMFC based on expertise each brought to the tasks involved in implementing the program. Objectives of each cooperator related to fishery implementation were as follows. 1. ODFW (Report A): Investigate the feasibility of implementing a large%a.le, floating trap-net fishery in the Columbia River downstream from McNary Dam. 2. WDW (Report B): Implement a systemwide (Columbia River below Priest Rapids Dam and Snake River below Hells Canyon Dam) sport-reward fishery. 3. PSMFC (Report C): Process and provide accounting for reward payments to participants in the sport-reward fishery. 4. CRITFC (Report D): Implement a systemwide angling fishery at eight mainstem dams on the Snake and Columbia rivers, and investigate juvenile salmonid consumption by channel catfish caught by dam anglers in the lower Snake River. 5. CRITFC (Report E): Investigate the efficacy of removing northern squawfish near hatchery release sites in the Bonneville pool. 6. CRITFC (Report F): Investigate the presence of northern squawfish concentrations in lower reaches of mainstem Snake River and Columbia River tributaries, and collect information regarding the origin and function of documented concentrations. 7. NMFS (Report G): Investigate differences in juvenile salmon survival associated with releases from Bonneville Hatchery at alternative release locations and following removal of northern squawfish by electrofishing. Background and rationale for the study can be found in Report A of our 1990 annual report (Vigg et al. 1990). Highlights of results of our work in 1993 by report are as follows. Report A Implementation of a Floating Trap-Net Fishery for Northern Squawfish in the Columbia River Downstream from McNary Dam 1. An experimental fishery using floating trap nets (modified Merwin traps) in the Columbia River downstream from McNary Dam was implemented to determine its effectiveness in catching large numbers of northern squawfish throughout this area. Special consideration was given to the potential for, and impact on, incidental catches of adult salmonids. 3 2. Information from a pre-season site survey was