During the survey reported in Part I, it became apparent that vegetational shading affected the incidences of certain species. The extent to which the distribution of stream fauna is influenced by direct or indirect consequences of shade or illumination was examined and an attempt was made to determine which species or groups are affected.
Three pairs of comparable sampling stations (stickles) were selected on the basis of their physical similarity, one of each pair being shaded and the other illuminated. Samples taken from these stations were compared and species found predominantly in shaded or exposed reaches were assessed.
Although certain species appeared influenced in their distribution, it appears that the population density is minimally affected and there is no overall effect on any group or family.