Across all Locations in the Big Russel, Romidepsin the most abundant sessile taxa identified from the frame grab analysis were hydroids (grouped), turf, and unidentified sponges. Prominent taxa in each location were red algae in Locations A, B, and C; bryozoan Flustra foliacea contributed towards the similarities between areas in Location B, keelworm Pomatoceros triqueter in Location D, and the bryozoans Cellepora pumicosa and Pentapora fascialis in Location E.From the video analysis, the most frequently observed taxa of the infrequent/conspicuous species in the Big Russel were the spiny sea star Marthasterias glacialis and the bloody henry sea star Henricia oculata, which contributed towards the similarities between areas in all locations.

Varying abundances of dead man’s fingers Alcyonium digitatum and the crabs; the spiny spider crab Maja squinado, the velvet swimming crab Necora puber, and the edible crab Cancer pagurus all contributed to differences along the north east-south west gradient between locations (Table 3).Table 3SIMPER analysis to determine the taxa whose abundance contributes most to the similarities seen between Locations for (a) abundant/encrusting and (b) infrequent/conspicuous.Despite the PERMANOVA results indicating differences between both the abundant/encrusting fauna and the infrequent/conspicuous fauna, the nMDS ordinations suggested that the pattern was different between the two groups (Figure 3). A clear gradient can be seen for the infrequent/conspicuous fauna that shows distinct grouping for each location, with locations situated next to their geographical neighbour.

There are no discernible patterns, however, for the common/encrusting fauna.3.1. Habitats in the Big RusselThe dominant habitat types identified were rock and boulders and cobbles. Sand was the dominant habitat type in some frame grabs in the north of the channel and is therefore included as a dominant habitat type despite being relatively rare throughout the rest of the Big Russel.The habitat type supporting the greatest abundance of taxa was rock (50 taxa), but the mean abundance of individuals was greatest on the boulders and cobbles (74.33 individuals site?1). Frames dominated by sand were by comparison species poor (12 taxa and 11 individuals site?1). Some taxa were found to dominate across all habitat types but their abundance was greater in frames where rock, boulders, or cobbles were present (Table 4).Table 4The ten taxa from frame grab analysis with the greatest abundance where rock, boulders and cobbles, and sand were the dominant habitat type. Data are percentage of frames containing each taxa for each habitat type (%). Gravel and pebbles were GSK-3 excluded …Epifauna were only present in sandy habitats when the frame contained hard substrata.