Marine Institute
SeaRover Dive Video

D673 Transect 23 Notable ophiuroid bed on mud veneered bedrock. P1. Water depth: 143m Feature: VMS data and local fisher knowledge

Highlights: Brittlestar bed - Ophiothrix fragilis Octopus - Eledone cirrhosa Pollack Demosponges - Axinella infundibuliformis?

Of note: A lot of octopuses.

Initially soft sediment with very little visible fauna apart from some hermit crabs and a few anemones. Crabs, octopuses and ophiuroids occur on hard ground. Large numbers of fish, particularly pollack, are present.

START VIDEO [00:00:00]/21:32. Notable colony of orange ophiuroid bed (Ophiothrix fragilis) on mud veneered bedrock. No samples . [1] [00:01:00] Soft sediment with scattered epifauna and occasional mobile species, including hermit crabs. Small gastropod shells (>1cm) found on sediment. ROV is moving upwards on moderate hill incline . [2] [00:06:00] Dense bed of orange ophiuroids (O. fragilis) on mud veneered bedrock. Marine snow throughout the dive. [00:13:00] Pollack aggregations appear more often. [00:19:00] Here substrata continue as mud veneered bedrock with sparse epifauna. Pollack are encountered frequently. [00:22:00] Pollack become abundant in this part of the transect. [3] [00:23:00] Here biotope changes into soft sediment. [00:28:00] Fields of cup coral on soft sediment. VIDEO END [00:28:39]/22:00.

Progression Start Duration Code Name
1[00:00:00]00:06:21SS.SMuSublittoral cohesive mud and sandy mud communities
2[00:06:22]00:17:00CR.LCRLow energy circalittoral rock
3[00:23:23]00:08:31SS.SMuSublittoral cohesive mud and sandy mud communities

Porifera
Porifera encrusting globose (pale) : 75 : F
Cnidaria
Pachycerianthus multiplicatus : 458 : R
Bolocera tuediae : 12 : R
Actinoscyphiidae sp. 1 (pink) : 1047 : R
Adamsia sp. : 1066 : R
Caryophyllia sp. 2 : 6 : F
Annelida
Lanice sp. 1 : 262 : R
Arthropoda
Chaceon affinis : 254 : R
Paguridae sp. : 205 : R

Munidopsis sp. : 1126 : R
Mollusca
Eledone cirrhosa : 1311 : R
Margarites sp. 1 : 277 : R
Hypsogastropoda sp. : 621 : R
Echinodermata
Heliometra glacialis : 216 : R
Crinoidea sp. : 1072 : R
Ophiothrix fragilis : 451 : A
Stichastrella rosea : 198 : R
Luidia sp. : 448 : O
Pseudarchaster sp. 1 : 433 : R
Ceramaster/Peltaster/Plinthaster sp. 1 : 234 : R

Echinoidea sp. 1 : 279 : R
Chordata
Scyliorhinus canicula : 1304 : R
Argentinidae sp. 1 : 1188 : R
Gadus morhua : 1316 : R
Pollachius pollachius : 1302 : F
Lepidorhombus boscii : 441 : R
Helicolenus dactylopterus : 227 : R
Neocyttus helgae : 563 : R

Number of species = 28

© Marine Institute, MERC Consultants, Bernard Picton 2022