An analysis of variations in community structure along a heavily fished fore reef slope in the Philippines indicates that depth and heterogeneity at the 1 and 10 cm scales were dominant structuring factors. Bottom temperature also appeared to be influential, but its effect was difficult to isolate from other factors related to depth. Comparisons of individual time slices of data taken 8 times on alternate months indicate that conclusions based on single sampling periods may be misleading. Groupings of the 18 sites differed substantially between sample periods, such that no two sites grouped together consistently throughout the study. (Author abstract).