2007 NWFSC Tidal Freshwater Genetics Results

Genetic Analysis of Juvenile Chinook Salmon for inclusion in 'Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, lower Columbia River, 2007. Final report submitted to the Bonneville Power Administration, Contract DE-AC05-76RLO1830.' Genotypic data were collected for 108 Chinook salmon and used in the genetic stock identification analysis. Results of the mixture analysis are presented in Table 1. Percentage estimates for four genetic stock groups (West Cascade Tributary Fall, Willamette River Spring, Deschutes River Fall, and Upper Columbia River Summer/Fall) ranged from 11% to 43%, all with non-zero lower 95% confidence intervals. Small contributions were also estimated for the West Cascade Tributary Spring (3%) and Snake River Fall (6%) stock groups. Results of individual fish probability assignments were summed by collection date (Figure 1) and site (Figure 2). Assignment probabilities for the most likely stock group for each individual ranged from 0.51 to 1.00 with approximately 60% of the assignments greater than 0.90 (data not shown). Nearly all of the low probability assignments were fish with assignments split between the Deschutes River Fall and Upper Columbia River Summer/Fall groups