Patchiness of epibenthic megafauna on the outer Grand Banks of Newfoundland

Photographic transects were used to investigate the distribution 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 1 m km⁻¹ than along transects with less gradient. Sessile, discretely motile, crawling, and swimming animals were spatially 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, crawling, and swimming animals. Local decoupling from substrate features was observed in swimming animals. Our results were consistent with the hypothesis that mobility determines the spatial scales over which the densities of benthic organisms are associated with substrate variability.