ABSTRACT. Photographic transects were used to inveshgate the hstribution of megafauna in relation to substrate variability on the outer Grand Banks. Sedimentary cover consisted of reworked glacial deposits arranged in alternating bands of gravel and sand. Megafaunal density was higher along transects with elevational gradients of l m km-' than along transects with less gradient. Sessile, discretely motde, crawhng, and swimming animals were spahally autocorrelated as Indicated by significant increase in variability with increase in length scale. Cross-correlation with substrate was stronger at large (> 100 m) than at smaller spatial scales in sessile, discretely motile, crawhng, and swimming animals. Local decoupling from substrate features was observed in swmming animals. Our results were consistent with the hypothesis that mobhty determines the spahal scales over which the densities of benthic organisms are assoc~ated with substrate variability.