Investigating the Extent of Hybridization between Native Bull Trout and Introduced Brook Trout in Alberta

Hybridization between bull and brook trout has been documented in the eastern slopes, but the full impact on bull trout populations has not been quantified. Emily Franks’ master’s project – co-supervised by Dr. Jon Mee, Mount Royal University and Dr. John Post, University of Calgary – did just that. This study quantified the extent of hybridization of individual trout, the population within a watershed, and populations across the East Slopes.

Franks found evidence that hybridization occurs across the East Slopes, beyond just the Elbow, Castle, and Oldman rivers that had been previously found. However, hybrids were generally rare, and Franks found only two second-generation hybrids out of approximately 1200 fish sampled, suggesting that the hybrids have problems reproducing. Read the thesis here.