A Comparative Perspective on Bull Trout from a Charr Fanatic

Bull trout have suffered from their common name and consequent taxonomic confusion. Ill-advised compilations of the biology, life history, evolution and behavior of “trout” by a variety of authors who should know better have kept Salvelinus confluentus in an ill-deserved limbo. Detailed studies of ontogeny, behavior and evolution of brook charr, lake charr and arctic charr provide our comparative perspective on bull trout. All these are related Salvelinus species, but they differ considerably in life history, behavior and habitat preferences. This diversity is our predictive framework for understanding bull trout. Charrs are circumpolar species of high northern latitudes. They are invaders and survivors in otherwise hostile environments created by retreating glaciers, with cold waters, low nutrients and few other fish species. They are highly adaptable in feeding habits, plastic in their phenotypic responses to their early rearing environment and capable of rapidly evolving in response to ecological opportunities. But those same features can restrict them to cold headwaters or deep lakes, or limit their abilities to compete with other species.