Marine Institute
SeaRover Dive Video

D473 Transect 26 Epifaunally rich sediment (cup corals, Acanella, xenophyophores, mixed burrowing anemones, & echinoids), a pink echinoid aggregation, pebbles/cobbles with trawl marks. Features of Interest: canyon, escarpments Water Depth: 1120-813 m

Highlights: Fish Sea urchins & anemones Black plastic Anemones Fish Epizoanthus pagurophilus Phelliactis anemone

The sediment is soft and the fauna is predominantly echinoids, cup corals, the bamboo coral Acanella arbuscula and occasionally the asteroid cf. Stichastrella rosea. Anemone assemblages are dense throughout, as well as cup corals these include cerianthids, halcampoids, hormathiid and interesting sun-shaped anemones. Large black solitary cf. hydroids are also present. The echinoid cf. Phormosoma placenta are plentiful as are sea pens; evidence of what is presumed to be crustacean burrows is widespread. Several large monkfish specimens were observed.

START VIDEO A [00:00:00]/ 18:21 [1]: Epifaunally rich flat /gently upsloping mud bottom with dense cup corals and xenophyophores, Acanella arbuscula is co-dominant, with diverse burrowing anemones among other fauna. [00:07:00] [2]: xenophyophores now occasional or absent, dominant cup corals and A. arbuscula, more occasional sea pens present. [00:08:00]: cup corals continue, now with Phormosoma placenta [00:15:00]: an aggregation of Zoroaster fulgens (robust morph) is encountered [00:17:00]: cup corals continue, no co-dominant species. [00:18:00] [3]: mixed burrowing anemones dominate, especially cf. Halcampoididae and Sagartiidae spp. The sediment may be becoming coarser, though it is hard to detect when the changes occur. [00:19:00] [4]: a few boulders host mainly barnacles, although several anemone species and corals are also present. Burrowing anemones continue on surrounding soft sediment. [00:19:00] [5]: continued mixed burrowing anemones (Halcampoididae, Sagartiidae, Ceriantharia), urchins frequent (Phormosoma placenta, dark Echinidae sp . (OTU1119)). Changing dominance in species, but assemblage consistent. [00:53:00] stop to view Epizoanthus/Paguridae spp. [00:57:00]: off bottom again. [01:05:00]: sediment now coarse sand/gravel, assemblage continues, although urchins now mainly Cidaris cidaris. [01:05:00]: stop, sediment disturbed, vision obscured. [01:08:00]: continue on, vision restored. [01:09:00] [6]: C. cidaris apparently dominates from the standard ROV viewing height, although up close halcampid anemones are clearly abundant. Added pebbles and cobbles host a sparse encrusting community dominated by serpulids. [01:10:00]: stop to view Epizoanthus/Paguridae spp. again, then for sampling C. cidaris (x3). 01:18: continue on. [01:19:00]: stop to photograph Phelliactis sp . [01:21:00]: continue. [01:25:00]: stop to sample C. cidaris (x5). [01:43:00]: continue. [01:46:00]: Epifauna becomes more sparse. [01:49:00] [7]: return to sand, rare pebbles, epifauna more sparse, urchins dominate still, here C. cidaris. [01:50:00]: dense aggregation of pink Echinidae sp. (OTU194) [01:51:00]: return to sparse urchins, again C. cidaris dominates. [01:51:00]: stopped for photography, vision obscured. [01:55:00]: continue, vision clear. [01:56:00]: stop, vision obscured. [01:56:00]: continue, clear vision. [01:57:00] [8]: patchy pebbles and cobbles/rare boulders again host sparse encrusting fauna dominated by serpulids, urchins on sand continue. END VIDEO A [02:00:00]/20:21.

START VIDEO B [02:00:00]/20:24. pebbles becomes denser, urchin/serpulid community continues. [02:02:00] [9]: Pachycerianthus multiplicatus becomes dominant in the sediment, although C. cidaris still present (serpulids still on rock). [02:05:00] [10]: back to C. cidaris dominance on sediment (serpulids still on rock). [02:08:00]: pebbles/cobbles becomes sparse, with rare boulders. [02:15:00]: sampling pushcores (x2) until [02:24:00]/ 20:49 END VIDEO B.

Progression Start Duration Code Name

Foraminifera
Syringammina fragilissima : 261 : O
Cnidaria
Cerianthidae sp. 1 : 2 : O
Pachycerianthus multiplicatus : 458 : O
Actiniaria sp. (large red) : 1120 : O
Actiniaria sp. 18 : 582 : F
Actiniaria sp. 20 : 605 : R
cf. Halcampoididae sp. : 984 : F
Sagartidae sp. (wide oral disc) : 1118 : O
Bolocera tuediae : 12 : O
Actiniidae sp. (sand Bolocera) : 41 : F
Halcampoididae sp. 1 : 23 : R
Actinauge richardi : 499 : R
Phelliactis sp. 1 : 255 : O
Hormathiidae sp. : 1098 : O
Caryophyllidae/Fabellidae (indet.) : 1058 : F
Caryophyllia sp. 5 (bullseye) : 584 : R
Epizoanthus sp. 1 (Paguridae associated) : 317 : O
Acanthogorgia cf. armata : 608 : O
Acanella arbuscula : 585 : F
Pennatulacea (indet.) : 1114 : R
Anthoptilum grandiflorum : 594 : O
Pennatula aculeata : 1046 : O
Pennatula cf. inflata : 1083 : R
Distichoptilum gracile : 1108 : O

Umbellula sp. : 581 : O
Branchiocerianthus norvegicus : 1069 : O
Corymorphidae sp. : 120 : R
Annelida
Bonellia viridis : 267 : R
Serpulidae sp. 1 : 106 : O
Arthropoda
Munida tenuimana : 339 : O
Paguridae sp. : 205 : O
Majoidea sp. : 1121 : R
Colossendeis sp. 1 : 1059 : O
Cirripedia sp. 1 : 82 : R
Mollusca
Colus sp. : 113 : R
Octopoda (indet.) : 659 : O
Teuthida sp. 1 : 1017 : R
Echinodermata
Crinoidea sp. : 1072 : R
Stichastrella rosea : 198 : R
Zoroaster fulgens : 988 : F
Pseudarchaster sp. 1 : 433 : R
Echinidae sp. (dark) : 1119 : F
Echinidae sp. (pink) : 194 : F
Echinidae sp. (white) : 559 : R
Cidaris cidaris : 211 : F
Phormosoma placenta : 555 : F

Araeosoma fenestratum : 188 : R
Echinothuroidea sp. : 1094 : R
Benthogone sp. : 432 : F
Mesothuria intestinalis : 536 : R
Chordata
Galeus melastomus : 1005 : R
Rajiformes sp. 1 (Neoraja caerulea?) : 652 : O
Hydrolagus cf. mirabilis : 1024 : O
Synaphobranchus kaupii : 440 : F
Brosme brosme : 258 : O
Molva dypterygia : 245 : O
Coryphaenoides guentheri : 577 : O
Coryphaenoides rupestris : 566 : O
Lepidion eques : 249 : O
Mora moro : 349 : O
Phycis blennoides : 1020 : O
Lophius piscatorius : 273 : O
Polyacanthonotus rissoanus : 552 : R
Notacanthidae sp. 1 : 1009 : R
Aphanopus carbo : 1097 : O
Zoarcidae sp. 1 : 259 : R
Actinopterygii sp. 3 : 930 : R
Myxine glutinosa : 383 : R

Number of species = 68

© Marine Institute, MERC Consultants, Bernard Picton 2022