Marine Institute
SeaRover Dive Video

D452 Transect 4 Limited geogenic reef with some discrete scleractinians & hydrozoan corals. Features of Interest: escarpment Water Depth: 751-668 m

Highlights: Stylasterids Madrepora Cable Lophelia & Madrepora Lophelia colonizing cable Blue ling Desmophyllum dianthus & Lophelia Stylasterid reef

This site is at the north eastern end of the North-west Porcupine Bank SAC. The substrate varies from soft sediment to rippled sand. Where there are dropstones or hard substrate the coral hydroid Pliobothrus symmetricus occurs. The echinoid Cidaris cidaris is present throughout, however conspicuous fauna is sparse. Fish species which occur here are the blackbelly rosefish Lepidion eques, northern cutthroat eels (Synaphobranchus kaupii), chimerids, sharks and monkfish (Lophius sp.).

START VIDEO A [00:00:00]/02:52 [1] The dive starts on flat soft muddy sediment with rare cobbles and boulders hosting Pliobrothus sp. (Hydrozoa) and discrete Lophelia pertusa colonies. [00:34:00] [2] With no further cobbles/boulders a flat area dominated by urchins occupies the majority of the dive, with END VIDEO A at 04:54

START VIDEO B [02:01:00]/04:54 by [02:17:00] the landscape starts to incline uphill with some pebbles in the sediment. [02:20:00] [3] The slope reaches an area of coarser sediment with rare cobbles and boulders becoming geogenic reef by [02:24:00]. This area is dominated by Lophelia pertusa interspersed with urchins on coarse sediment. [03:18:00] [4] a carbonate slope with muddy veneer gives rise to and escarpment of horizontal ledges with overhanging shelves dominated by Desmophyllum cf. dianthus and discrete L. pertusa colonies. Several clumps of snagged fishing gear are encountered here. [03:27:00] [5] Proceed over the top of the carbonate escarpment feature, again meeting cobbles and boulders on coarse sediment with discrete L. pertusa colonies and urchins. The sediment quickly thins to mud/sand again and cobbles/boulders become sparse. [03:32:00] [6] Back to soft sediment with urchins and a brief encounter with a small octopus before the ROV comes off bottom at END VIDEO B [03:34:00]/06:28.

Progression Start Duration Code Name
1[00:00:00]00:34:42M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand
2[00:00:00]02:02:40M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand
3[00:19:06]00:58:14M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand
4[01:17:21]00:08:52M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand
5[01:26:14]00:01:47M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand
5[01:28:02]00:03:25M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand
6[01:31:28]00:02:05M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand

Porifera
Porifera encrusting sp. 1 (white) : 1 : R
Porifera encrusting sp. 15 (yellow) : 58 : R
Porifera encrusting sp. 18 (cream) : 105 : R
Blue Porifera encrusting : 800 : R
Cnidaria
Cerianthidae sp. 1 : 2 : O
Pachycerianthus multiplicatus : 458 : R
Actiniaria sp. 1 : 4 : O
Actiniaria sp. 13 (pink/purple) : 478 : O
Bolocera tuediae : 12 : F
Phelliactis sp. 1 : 255 : R
Corallimorphidae sp. 2 : 43 : R
Desmophyllum cf. dianthus : 335 : O
Lophelia pertusa : 250 : C
Madrepora oculata : 251 : C
Anthomastus grandiflorus : 278 : R
Hydrozoa (bushy) : 50 : R
Pliobothrus sp. : 207 : F
Annelida
Bonellia viridis : 267 : R

Sabellidae sp. 1 : 54 : R
Serpulidae sp. 1 : 106 : O
Arthropoda
Chaceon affinis : 254 : R
Paguridae sp. : 205 : R
Pandalus borealis : 57 : R
Cirripedia sp. 1 : 82 : O
Mollusca
Octopoda (indet.) : 659 : R
Anomiidae sp. 1 : 32 : O
Teuthida sp. 1 : 1017 : R
Bryozoa
Reteporella sp. : 204 : R
Echinodermata
Koehlermetra porrecta : 315 : R
Pseudarchaster sp. 1 : 433 : R
Henricia sanguinolenta : 208 : R
Ceramaster/Peltaster/Plinthaster sp. 2 : 388 : R
Echinus sp. : 445 : R
Cidaris cidaris : 211 : F
Araeosoma fenestratum : 188 : F

Psolus squamatus : 252 : O
Chordata
Ascidiacea sp. 2 : 20 : R
Galeus melastomus : 1005 : R
Chimaera monstrosa : 265 : O
Hydrolagus cf. mirabilis : 1024 : O
Synaphobranchus kaupii : 440 : F
Beryx decadactylus : 1025 : R
Merlangius melangus : 1019 : R
Molva molva : 654 : R
Nezumia aequalis : 1003 : O
Coelorinchus caelorhincus : 303 : O
Lepidion eques : 249 : F
Mora moro : 349 : O
Phycis blennoides : 1020 : O
Lophius piscatorius : 273 : R
Trichiurus lepturus : 1016 : O
Helicolenus dactylopterus : 227 : O
Actinopterygii sp. 4 : 1006 : R

Number of species = 53

© Marine Institute, MERC Consultants, Bernard Picton 2022