Marine Institute
SeaRover Dive Video

D476 Transect 34 Sand with patches of pebbles, urchins dominate, dropstones in depressions with a Bolocera & a fish each. Features of Interest: canyon, escarpments Water Depth: 862-687 m

Highlights: Red sea urchins Bolocera anemone & fish

The substrate is predominantly rippled sand with some stones and pebbles. No obvious fauna is visible on the very steep incline (730 m). Echinoids are present at the base of the canyon with c.f. Echinus sp. being common. Epizoanthus pagurophilus and its symbiotic hermit crab Parapagurus pilosimanus are evident at the base of the canyon but are not observed on the side of the canyon. White smooth column hormathiid anemones occur regularly. Further up the slope, large anemones are present on the sand. A distinct dense patch of the small dark anemones are evident here; this is different from other sites were they tend to be scatter widely over a large area. Northern cut-throat eels are present throughout but are more common at the base of the slope. Greater forkbeards are recorded on the mid to upper slope. The hydroid Pliobothrus symmetricus occurs on the stony ground towards the top of the canyon. An unusual depression feature was noted at this site.

START VIDEO [00:00:00]/23:05 [1] Rippled sand and pebbles with mixed urchins (especially pink Echinidae sp. , OTU194). The ROV stops and starts several times. [00:03:00] interesting footage of a Synaphobranchus kaupii with a juvenile Trichiurus lepturus in its mouth (despite its prey being 2/3 its own body length). [00:09:00] Start properly. Pebbles are scattered and occur patchily on the rippled sand (e. g. no pebbles [00:15:00]-[00:21:00], [00:24:00]-[00:27:00], sparse [00:33:00]-[00:36:00], none [00:36:00]-[00:39:00]). [00:15:00]-[00:19:00] There are many hermit crabs (Paguridae spp.) with associated Epizoanthus sp . in this area. [01:04:00] [2] rippled sand with no dominant species and sparse epifauna, mainly encountering only small S. kaupii eels. [01:10:00] More consistent occurrence of sparsely encrusted pebbles and rare cobbles/boulders are mosaicked with the rippled sand, serpulid worms dominate the hard substrate. [01:15:00]-[01:16:00]. A dense patch of Pachycerianthus multiplicatus. [01:19:00] fewer pebbles but sparse/rare cobbles/boulders, often as a solitary dropstone in a depression [01:19:52] are colonised by serpulids and a Bolocera tuediae anemone. These usually have one large fish associated, either a Brosme brosme or a Phycis blennoides. [01:36:00] -[01:39:00] and [01:46:00]-[01:49:00] Stopped to sample Parastichopus tremulus. [01:51:00] - [01:53:00] moving right to investigate, stop, and image another depression and dropstone. Continue until END VIDEO [01:59:00]/01:05

Progression Start Duration Code Name
1[00:00:00]00:36:12M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand
1[00:36:13]00:28:15M.AtMB.Sa.UrcComUrchin dominated community on Atlantic mid bathyal sand
2[01:04:29]00:54:58M.AtMB.SaAtlantic mid bathyal sand

Cnidaria
Pachycerianthus multiplicatus : 458 : O
Actiniaria sp. 1 : 4 : O
Actiniaria sp. 27 : 976 : R
Sagartidae sp. (wide oral disc) : 1118 : R
Bolocera tuediae : 12 : O
Actiniidae sp. (sand Bolocera) : 41 : O
Actinauge richardi : 499 : O
Phelliactis sp. 1 : 255 : O
Epizoanthus sp. 1 (Paguridae associated) : 317 : O
Annelida
Serpulidae sp. 1 : 106 : R
Arthropoda
Chaceon affinis : 254 : R
Paguridae sp. : 205 : O
Mollusca

Colus sp. : 113 : R
Sepiolidae sp. : 1095 : R
Echinodermata
Crinoidea sp. : 1072 : R
Stichastrella rosea : 198 : O
Pseudarchaster sp. 1 : 433 : O
cf. Hymenaster (yellow) : 1174 : R
cf. Echinus (deep pink spine) : 1129 : R
Echinus sp. : 445 : R
Echinidae sp. (dark) : 1119 : R
Echinidae sp. (pink) : 194 : O
Cidaris cidaris : 211 : R
Elpidiidae (indet.) : 1122 : R
Parastichopus tremulus : 266 : O
Chordata
Synaphobranchus kaupii : 440 : O

Merlangius melangus : 1019 : O
Brosme brosme : 258 : O
Molva molva : 654 : R
Nezumia aequalis : 1003 : O
Lepidion eques : 249 : R
Mora moro : 349 : R
Phycis blennoides : 1020 : O
Polyacanthonotus rissoanus : 552 : R
Trichiurus lepturus : 1016 : O
Helicolenus dactylopterus : 227 : R
Actinopterygii sp. 3 : 930 : R
Actinopterygii sp. 4 : 1006 : R

Number of species = 38

© Marine Institute, MERC Consultants, Bernard Picton 2022