Open-Water Movements of the Cutthroat Trout (Salmo clarki) in Yellowstone Lake After Displacement from Spawning Streams

Abstract

Cutthroat trout were taken from their spawning streams (June–August 1964 and 1965). A Styrofoam float was attached and fish were tracked from two release points. They moved generally shoreward (eastward). Of 120 fish tracked when the sun was visible, 68% went toward shore, 19% went away from shore, 4% showed random movement, and 8% were lost. Of 20 fish released when the sun was obscured, 30% went toward shore, 30% went away from shore, 30% showed random movement, and 10% were lost. Movement toward the eastern shoreline was less pronounced for fish liberated at a mid-lake release point. No directional preference was shown with respect to surface currents. There was no evidence that specific landmarks were used for orientation, but the sun may have served as a reference point since fish traveled farther and showed a stronger shoreward tendency on sunny days.