Extreme spatial variability in sessile assemblage development in subtidal habitats off southwest Australia (southeast Indian Ocean)

► Multi-scale spatial variability in the development of subtidal sessile assemblages was examined in southwest Australia. ► Variability in assemblage structure between locations 100 s of kilometers apart was extreme. ► Panel assemblages at one of the locations comprised a single macrofaunal species after 14 months. ► Feeding by demersal fish and low influx of dispersal particles were most likely explanations.