Trait means versus time exposed to fish predation. Linear regressions of body size (A) and age at maturity (B) versus the number of years co-occurring with introduced salmonids. Points left of the dashed line are lakes that have never contained introduced salmonids. These points have been offset to the left for visualization. The regression analysis treated these three points as zero years of co-occurrence with fish.
Fisk et al. BMC Evolutionary Biology 2007 7:22 doi:10.1186/1471-2148-7-22