Comparative performance of sham radio-tagged and PIT-tagged juvenile salmon

From 23 to 28 April 1999, we released 1,113 fish with gastrically implanted sham radio tags, 1,113 fish with surgically implanted sham radio tags, and 1,071 PIT-tagged fish into the tailrace of Lower Granite Dam. Sham radio tags were similar in size and weight to commercially manufactured coded radio tags forjuvenile salmonids. A PIT tag was embedded in each sham-tag casing by the manufacturer. Migration rates, detection probabilities, and survival were estimated from PIT-tag detections ofindividual fish at Little Goose, Lower Monumental, McNary, John Day, and Bonneville Dams. Differences among migration rates, detection probabilities, and survival relative to the PIT-tagged groups were evaluated by analysis of variance (ANOVA). Contract no. W66QKZ91521282