Potentially important, miscellaneous, qualitative observations of four field studies of spawning migrations of arctic grayling (thymallus arcticus) through highway culverts are discussed. Problems associated with culvert outlets, inlets, and barrels are described together with observed methods that fish use to negotiate culverts. The importance of location where fish actually swim in culverts is discussed. Limited observations of effects of culvert skew on culvert barrel flow patterns indicate such skew can make fish passage less difficult. The necessity of recognizing red muscle and white muscle power and energy capabilities of fish attempting to pass through culverts is indicated. Observations of fish attempting to enter a small fish ladder and a difficult culvert indicate that water-produced noise may attract fish to relatively small passage devices. Fish are observed to resort to leaping to enter difficult passage situations. Thispaper appears in transportation research record no. 1224, Rest areas, wetlands, and hydrology.
Abstract