3Background JOHN DAY RESERVOIR (1983-86) Losses to predation Diet, salmonidsPopulationAn analysis of April – August predator diet composition indicated that although j-sals were consumed by all 3 predators; they were main prey item selected by NPM. Predator population estimates projected the size of the piscivore ~135,000 individuals – of which almost 2/3rds were NPM. The long and short of it is, based on these 2 things, they were able to estimate that ~1.4 million smolts were consumed by preds annually in the JD reservoir - 78% of which were consumed by NPM.
4John Day Reservoir (continued) Northern pikeminnow predation increased with sizeMove quickly through some background that led to the project, some history/accomplishments, then plans for
5Background SYSTEM-WIDE (1990-92) Loss to Predation = 8% of Population Predation Relative to John Day ReservoirBelow Bonneville Dam = 800%Lower Columbia Reservoirs = 325%Lower Snake River Reservoirs = 40%Loss to Predation = 8% of Population
6Background 10-20% Exploitation = 50% Reduction in Predation Assumes no compensation by remaining predators: abundance, growth, fecundity, age structure, et al.Fisheries implemented systemwide in 1991This came from evaluation.
8Fishery Implementation and Harvest Incidental catch of returning NPMP anglers
9Dam Angling (ODFW, CRITFC, et al.) Gill Net (CRITFC, YIN, et al.) Northern Pikeminnow FisheriesSport Reward (WDFW)1991-PresentDam Angling (ODFW, CRITFC, et al.)Gill and Dam: 159,000Gill Net (CRITFC, YIN, et al.)
10Sport Reward Harvest,Average 174,107; record harvest 2004, 267,215
11Sport Reward Effort, 1991-2005 Angler Days (in thousands) Average 40,258 angler-days/year. Peak 1992, 88,495
122005 Sport Reward Harvest by Reservoir Below Bonneville87,575Ice Harbor1,732Bonneville55,097Lower Monumental1,983The Dalles30,153Little Goose33,828John Day328Lower Granite12,073McNary18,588Harvest by Reservoir
14EvaluationIncidental catch of returning NPMP anglers
15Northern Pikeminnow Exploitation, Sport Reward (> 250 mm FL),
16Predation Relative to Pre-NPMP Median reduction in predation based on Friesen and Ward’s (1999) model. Net gain estimated at 3.8 million smolts.78%
17Compensation?Abundance, density, age, growth, fecundity, consumption, conditionNorthern PikeminnowNoSmallmouth BassMaybeSMB Relative density increases in certain areasWalleyeNo
18Northern Pikeminnow Electrofishing Catch Rates, John Day Reservoir
19Diet Composition (samples with identifiable fish), Columbia and Snake Rivers, 1999,FamilyNorthern pikeminnow(N = 291)Smallmouth bass(N = 364)% Salmonidae69.720.7% Cottidae10.053.0% Clupeidae8.80.9% Cyprinidae3.27.2% Catostomidae0.06.3% Cobitidae0.2% Ictaluridae1.6% Percopsidae1.9% Gasterosteidae7.54.9% Centrachidae0.63.0% Percidae0.5
20SMB Consumption Index – John Day Forebay This SMB consumption index takes into account inputs such as stomach contents, fish wt., and temperature. Considering the increases in SMB relative density in the forebay area of the reservoir I’d thought we’d take a look at how many jsals are being consumed by SMB in this area. Consumption of smolts by SMB does not appear to have increased in the forebay in either spring or summer, and may actually be decreasing, slightly, on a per bass basis.
22Recent Changes and Plans for 2006 Institutionalize Reward StructureRolling Biological IndexingRe-institute Dam AnglingUpdate Predation ModelMulti-year Exploitation RatesAddition of Two Sport-reward StationsRewards. Indexing in response to Bi-Op. Limited Dam angling by USDA on test basis. Respond to program review w/updated model and exploitation. New stations in Umatilla and Cascade Locks
23NPMP Accomplishments, 1991-2005 Over 2.7 million Northern Pikeminnow RemovedLow Impact to Resident / Anadromous Species>10% Exploitation Achieved in 13 of 15 YearsEstimated 22% Reduction in Salmonid PredationCompensation by Remaining Predators MinimalCredible Science: ~30 Journal Articles PublishedCost EffectiveMultiple audits, biological and economic, all concluded the program was efficient (with tweaks)