At the stations five random quadrats were sampled per zone along an imaginary transect with the number of zones differing at the stations, but usually being five. Zones were identified according to the key species or communities present in the zone. At each sampling position all species within the randomly selected sampling quadrat (0.5 x 1m) were recorded and their abundance estimated, either by estimating the percentage coverage (sessile species like algae and mussels) or by counting the individuals (mobile species like limpets and whelks). Percentage coverage was recorded as primary – directly attached to rock or growing in sand, secondary – attached to another organism (e.g. growing on a mussel) or canopy cover. Abundances were also recorded as primary (directly on rock or sand) or secondary (on another organism). Organisms were identified to species level where possible.