In the lower Fraser River, British Columbia, movement and abundance are assessed by acoustic tags and mark recapture methods. While the model developed by Robichaud, English and Nelson assumes a closed homogenous population, acoustic tags and mark-recapture data shows that they are sedentary during the winter months and mobile in the spring and fall, with data indicating that they leave the Fraser River and enter the Strait of Georgia during their mobile periods; this conclusion has been validated by microchemical evidence of marine exposure in Fraser River white sturgeon fin rays.