The Brown trout displays widely divergent life history strategies involving, variously, usage of streams, rivers, lakes, estuaries and the sea. The sea trout is the full sea-going form, it is very common and competes with salmon for the position of the most sought after migratory salmonid in many countries. Its use of freshwater, estuaries and coastal waters gives it a unique position as a sentinel species of environmental quality across these habitats. Although a commercially and recreationally...