Highlights: 00:56:31 ROV samples Cidaris cidaris sea urchin 01:18:00 Plastic bag upright on seabed 02:04:42 Lophelia & cerianthid anemones 02:21:47 ROV collects sample of Lophelia 02:31:53 ROV collects Lophelia with gastropod shell

This transect was previously undertaken during the 2009 Offshore Reef Survey (Guinan & Leahy 2009) and a repeat dive on this transect was carried out during the current study to monitor change, if any, over time. A thin layer of soft sediment (coarse sand with pebbles) over harder ground is apparent at the base of the mound. Further up the slope the sediment is coarse with occasional rocks and dropstones. The hydroid coral, Pliobothrus symmetricus, occurs on stones and rocks. The echinoid Cidaris cidaris is common while cf. Calveriosoma fenestratum occurs occasionally. The northern cutthroat eel and Lepidion eques are also present.

Moving up the canyon the incline is steeper; initially the fauna is sparse but diversity increases on reaching areas of coral rubble and areas of live Lophelia pertusa. Species such as Bathypathes sp., Chirostylus sp., C. cidaris, P. symmetricus and cf. C. fenestratum are recorded here, fish species include L. eques. Continuing up the slope L. pertusa becomes denser. The northern cutthroat eel, L. eques, the blackbelly rosefish, P. symmetricus, bamboo coral and the crab Chaceon sp. occur among the reef. In the patches of soft sediment cerianthids are evident. A dense area of reef continues over the top of the steep slope and many fish are evident in the water column. A long gully is present in which approximately 20 blackbelly rosefish are gathered, the substrate is featureless sand. The substrate on the subsequent incline is thought to be carbonate with a thin veneer of fine sediment.

Moving up the steep slope after this gully the density of L. pertusa increases and is at its densest towards the top of the incline. Two colour morphologies, white and orange, of L. pertusa are present here. Crinoids, echinoids, anemones, including hormathiid anemones are present. Further up the slope there are very dense patches of coral rubble, with cerianthids and the occasional clump of live Lophelia. Continuing up this slope the clumps of Lophelia reef increase in size and become denser, with Anthomastus sp., anemones and bamboo corals occurring amongst the reef.

START VIDEO [1] [00:00:00]/16:07 Transect starts on coarse sandy sediment with Cidaris cidaris, 3 C. cidaris sampled. [2] [00:26:00] Sediment becomes coarser with some gravel and pebbles and occasional cobbles/boulders, mainly Pliobrothus sp. on cobbles. [3] [00:30:00] Return to coarse sediment with coral gravel constituent, some C. cidaris (3 sampled) but when zoomed for sampling brachiopods become apparent. [4] [00:43:00] (Transitional community) Reached edge of carbonate mound, sand/coral gravel with patchy/sparse mosaicked reef sampled 3 C. cidaris, 1 Lophelia pertusa. Change of direction and travel upslope [5] [01:15:00] Dense coral reef of L. pertusa and Madrepora oculata on steep slope, summit and downslope to saddle area. [6] [01:20:00] Area of coral rubble/gravel mosaicked with reef. May indicate areas of trawl damage. [7] [01:20:00] Dense coral reef summits, school of black cardinal fish (Epigonus telescopus [01:22:05]) encountered over saddle between summits [8] [01:25:00] Saddle region with rippled coarse sediment (sand/coral gravel) and abundant Blackbelly Rosefish (Helicolenus dactylopterus) [9] [01:26:00] Mosaic of C. cidaris on coarse sediment and patchy/sparse coral reef [10] [01:29:00] Low lying coral reef on steep upslope. [11] [01:37:00] Another area of coral rubble/gravel mosaicked with reef. May indicate areas of trawl damage. [12] [01:38:00] Cliffs of carbonate terraced with areas of coral rubble/gravel, burrowing anemones (Ceriantharia) dominate. [13] [01:42:00] Dense reef. [14] [01:44:00] Coral gravel/sand with patchy/sparse mosaicked reef END VIDEO A 17:58

START VIDEO B [01:51:46]/18:00 Continued gravel/sand and reef mosaic. [15] [01:53:00] Relatively flat coral gravel/sand with C. cidaris. Shoal of juvenile Synaphobranchus kaupii (overlaps previous reef patch too). [16] [01:59:00] C. cidaris continues mosaicked with sparse/patchy reef. [17] [02:00:00] Denser but patchy reef interspersed with cerianthids on coral gravel. END VIDEO B 18:44