Macroalgal coverage from video surveys of long spined sea urchin (Centrostephanus rodgersii) barrens habitat, eastern Tasmania, Australia (2001-2002)

The macroalgal cover was recorded from video surveys of the spatial extent of C. rodgersii "barrens" on rocky reef habitats using a towed underwater video system. Sampling took place at 13 regions along the east coast of Tasmania, each comprising 3 subsites. Thus, at each site, ca. 6-7 km of inshore rocky reef was surveyed for barren habitat using this method, with the entire survey covering > 80 km of reef.
Substratum types were resolved as either "unclassified reef" if the substratum type was unclear (usually where macroalgal cover prevented a clear view of the substratum) or, where the substratum could be discerned, "flat rock" with little apparent relief, "boulder reef", "cobble", "gravel", "pebble", or "sand". Habitat types denoted either C. rodgersii barrens, or habitat dominated by particular canopy-forming species.
Absence records are recorded. Macroalagal cover per taxa is measured as percent cover in 3 categories of 'Dominant algal species, >80% of canopy','Common algal species, 40-80% of canopy' and 'Rare algal species,