Few hatchery brook trout genes present in Pennsylvania watershed wild fish
(PHYSorg.com Biology)

Despite many decades of annual brook trout stocking in one northcentral Pennsylvania watershed, the wild brook trout populations show few genes from hatchery fish, according to researchers who genotyped about 2,000 brook trout in Loyalsock Creek watershed, a 500-square-mile drainage in Lycoming and Sullivan counties celebrated by anglers for its trout fishing.