When do sea trout come up our rivers?
The timing of upstream migration varies among regions. In Scotland, early-running sea trout stocks ascend some of our larger river systems from about April through to early June. These fish are more likely to have originated within headwater streams. Lower tributaries often are populated more by later-running fish, some coming into the rivers so late that angling is closed. Early-running sea trout at first are relatively easily caught by angling as they move upriver. Soon they settle down for the summer in accessible lochs (lakes) or, often in rivers, in slow, deeper pools, hiding during daylight hours under overhanging banks or tree cover, or overhead water turbulence, jumping and moving more during and after dusk. Smaller in body size on average than most salmon, they have a tendency to progress upriver during the hours of darkness at times through remarkably shallow water. In the absence of automatic fish counters and video equipment sited at key points of passage, adult sea trout stock abundance is difficult to estimate.