In any salmon conservation program, the successful escapement of the mature adults to the spawning grounds in fresh water is an important factor. The presence of any obstruction which might totally bar the fish or merely delay their ascent upriver may be of appreciable significance. With this in mind the present study of Moricetown falls, known to be one of the possible major obstruc­tions to the upstream migration of Pacific salmon in the Skeena River system, was undertaken by the Fisheries Research Board of Canada as part of the Skeena River Salmon Investigation.