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Notes on new benthic invertebrates from the southern Irish Sea

ISSN 1466-0369
Winter 2009/10 Number 27
Mackie, A.S.Y., Darbyshire, T., Bamber, R.N. & Turner, J.A. 2010.
Notes on new benthic invertebrates from the southern Irish Sea.
Porcupine Marine Natural History Society Newsletter 27: 24-27.
PMNHS Newsletter No.27 Winter 2009/10
Haploniscidae, Mictosomatidae, Ischnomesidae.
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5, 15-27.
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Report, Vol. 6: 1-320, pl. 1-19.
Notes on new benthic
invertebrates from the southern
Irish Sea
Andrew S.Y. Mackie1, Teresa Darbyshire1, Roger N.
Bamber2 & James A. Turner1
1 Amgueddfa Cymru — National Museum Wales,
Cathays Park, Cardiff CF10 3NP
2 ARTOO Marine Biology Consultants LLP, Ocean
Quay Marina, Belvidere Road, Southampton SO14
A number of new, or potentially new, benthic
invertebrates were found during the recently
published Habitat mapping for conservation
and management of the Southern Irish Sea
(HABMAP) study (Robinson et al. 2009a,
b; Mortimer and Wilson 2009). Several of
these were additionally remarkable from a
distribution and biogeography viewpoint.
HABMAP was a four-year seabed mapping
project covering the southern part of the Irish
Sea. The project was partly funded by the
European Union INTERREG IIIA programme
for Welsh-Irish collaboration (www.habmap.
org), and led by the Countryside Council for
Wales and Trinity College Dublin. Biologists,
geologists and modellers worked closely
together to characterize, map and model
seabed habitats in the study area.
The four species included in this account
comprise two polychaetes, one echiuran and
one pycnogonid. Recent molecular studies
(e.g., Struck et al. 2007) contradict traditional
classification schemes and the polychaetes
and echiurans are considered annelids, along
with the clitellates (oligochaetes, leeches)
and sipunculans. Relationships within the
Annelida are still uncertain.
Darbyshire and Mackie (2009) described a
new species of Diplocirrus (Flabelligeridae),
D. stopbowitzi (Fig. 1). This species had
been recognized in previous BIOMÔR surveys
(e.g., Mackie et al. 1995), but additional
material collected in the HABMAP study and
subsequently (Blyth-Skyrme et al. 2008)
helped facilitate a detailed description. The
retractable gills were found to be very similar
to the same two forms present in D. glaucus
(Malmgren), the species most commonly found
in UK waters. The two species differ in the
appearance of the epidermal papillation, and
in the lack of elongated anterior bristles in D.
Fig. 1. Diplocirrus stopbowitzi, lateral view (gills and palps
retracted). Note small ‘globular’ epidermal papillae.
Furthermore, the two species inhabited different
sediments and did not co-occur. Diplocirrus
glaucus was mainly recorded from muddy sand,
PMNHS Newsletter No.27 Winter 2009/10 25
though present in sediments ranging from mud
to sandy gravel (18-145 m). In contrast, the
new species was common in coarser sediments,
particularly the sandy gravels and gravelly
sands found in the St George’s Channel area
in the middle of the southern Irish Sea (Fig.
4). Diplocirrus stopbowitzi has subsequently
been recorded from the Isles of Scilly (pers.
obs.), southwest Ireland (McCormack, pers
comm.) and northwest Scotland (Hamilton,
pers. comm.)
The other new polychaete considered here is
currently being described as part of a larger
revision (Darbyshire and Mackie) and is, as
yet, unnamed. It belongs to Uncispio, a poorly
known spioniform genus with characteristically
large hooked bristles on the last few tail
segments. At present, the genus is placed in
its own family, the Uncispionidae.
The only known species U. hartmanae Green,
1982 occurs in the Pacific, off California (clay,
222 m), and was described from three small
specimens less than 5 mm long. Specimens of
the new Irish Sea species are up to about 15 mm
in length. They were found in abundance (up
to 251/0.2 m2) at two of the deeper locations
(127 and 169 m) to the west of Anglesey (Fig.
4) and are a major component of a newly
recognized boulder clay habitat (Robinson et al
2009a). A single specimen was recorded from
the same area during an earlier survey carried
out by Unicomarine (Worsfold, pers. comm).
The two posterior fragments collected from
HABMAP station 13, Arklow Bank (28 m), off
the Irish east coast (Fig. 4) were from a sample
recorded as slightly gravelly sand. At first
sight this appears at variance with the Uncispio
dominated habitat off Anglesey. However, it
must be noted that, the boulder clay there
occurred in close proximity to coarser sandy
sediments; grabs would collect sand, clay, or
a mixture of both. In some Sediment Profile
Imagery (SPI) photographs the sand was shown
overlying the clay. It may well be that the new
Uncispio is more widespread than presently
known and can occur wherever boulder clay
is exposed on the seabed.
The echiuran is unusual and appears to belong
to the genus Prometor Fisher, known for 4
species described from the Pacific Ocean (see
Stephen and Edmonds 1972). In life the
specimens are white and translucent with
strap-like proboscises that are characteristically
expanded as shallow somewhat scalloped
funnels (Fig. 2).
Fig. 2. Prometor sp., anterior showing paired hooked
chaetae and scalloped funnel-like base of proboscis.
The species was found in the same boulder
clay samples off Anglesey as Uncispio (Fig.
4) and shows some similarity to P. procula
Hartman, 1960 known from stiff clay, in
deep water (1821 m) off southern California.
However, the Irish Sea material was generally
small (up to about 1.5 cm long; proboscis
variable, up to twice body length) compared
to the large (19 cm) Californian species. The
largest specimen (lacking the proboscis) was
2.7 cm long. Biseswar (2006) described a
single unnamed specimen of this genus from
the Porcupine Abyssal Plain (4844 m). The
Irish Sea specimens share the same lobed
cup at the base of the proboscis as this small
specimen, but the paired hooks are much more
curved. Additional material may be necessary
to resolve the taxonomy.
The new sea spider, Sericosura conta Bamber,
2009 (Fig. 3), represents the first discovery of
the genus in European waters. Sericosura Fry
& Hedgpeth is a genus of the Ammotheidae
obligately-associated with chemically-reduced
seabed habitats, including hydrothermal vents
and cold-seeps. The species are generally
robust, with the cephalon characteristically
flared anteriorly, and the chelifores (when
present) mounted on the anterior face of the
cephalon. The palps are either 7- or 9-articled.
PMNHS Newsletter No.27 Winter 2009/10
The cement gland in the male is mostly
mounted proximally on the femur, although
mesially in one species, and its presence has
not been discovered in one other (despite
its being extremely common): in all other
ammotheids, the cement gland is distal on
the femur. Sexual dimorphism is marked in
the ovigers, and in the posterior walking legs
in one species. S. conta is distinguished from
its congeners by its very compact chelifores,
and by the auxiliary claw on the walking legs
being as long as the main claw (shorter in all
other species).
Fig. 3. Sericosura conta, lateral view. Note presence of
short chelifores and 9-articled palps, respectively dorsal
and lateral to the stout proboscis. First leg present, others
now detached.
The type species, S. mitrata Gordon, from
the Antarctic, was previously the shallowest
species known (recorded depth range 106-2154
m). However, the new Irish Sea species occurs
in very shallow water (20 m). The other eight
recognized species are from the mid-Atlantic
Ridge (1), Antarctic (1) and Pacific Ocean
(6). The genus is usually found associated
with deeper hydrothermal-vent or seep areas
associated with oceanic ridges, at depths of
850-2600 m. The seabed at the type locality
off Wicklow Head (Fig. 4) was stony, though it
is possible that a gas seep is present there: gas
seeps are known to occur at various locations
in the Irish Sea (Croker 1995; Croker et al.
2005). Intriguingly, S. conta is most similar to
S. verenae (Child), recorded from the Northern
Pacific vent systems of Juan de Fuca, Gorda
and Explorer Ridges, the Endeavour Segment,
Axial Seamount and off northern California.
The new species has a body about 4 mm across
with legs over 15 mm long (Fig. 3).
We gratefully acknowledge the contributions
of all those involved in the HABMAP project.
We are grateful also to Sue Hamilton (Marine
Consultant, Currie, Scotland), Eddie McCormack
(Aqua-Fact International, Galway, Ireland)
and Tim Worsfold (Unicomarine, Letchworth,
England) for additional distributional
Bamber, R.N. 2009. Two new species of
Sericosura Fry & Hedgpeth, 1969 (Arthropoda:
Pycnogonida: Ammotheidae), and a
reassessment of the genus. Zootaxa 2140:
Biseswar, R. 2006. Additions to the deep-sea
echiuran (Echiura) fauna of the North-East
Atlantic. Zoosystema 28: 853-864.
Blyth-Skyrme, V., Lindenbaum, C., Verling, E.,
Van Landeghem, K., Robinson, K., Mackie, A.
and Darbyshire, T. 2008. Broadscale biotope
mapping of potential reefs in the Irish Sea
(northwest of Anglesey). JNCC Report 423:
210 pp.
Croker, P.F. 1995. Shallow gas accumulation
and migration in the western Irish Sea. In:
The Petroleum Geology of Ireland’s Offshore
Basins (Eds P.F. Croker and P. M. Shannon).
Geological Society of London Special Publication
No. 93: 41-58.
Croker, P. F., Kozachenko, M. and Wheeler,
A.J. 2005. Gas-related seabed structures in
the western Irish Sea (IRL-SEA6). Technical
report produced for Strategic Environmental
Assessment - SEA6. 120 pp. [www.offshore-sea.
Darbyshire, T. and Mackie, A.S.Y. 2009.
Two new species of Diplocirrus (Polychaeta:
Flabelligeridae) from the southern Irish Sea
and South Africa. In: Proceedings of the 9th
International Polychaete Conference, Portland,
PMNHS Newsletter No.27 Winter 2009/10 27
Maine 2007 (Eds N.J. Maciolek and J.A. Blake).
Zoosymposia 2: 91-103. [
Green, K.D. 1982. Uncispionidae, a new
polychaete family (Annelida). Proceedings
of the Biological Society of Washington 95:
Hartman, O. 1960. Systematic account of some
marine invertebrate animals from the deep
basins off southern California. In: The benthic
fauna of the deep basins off southern California,
Part II (O. Hartman & J. L. Barnard). Allan
Hancock Pacific Expeditions 22(2): 69-215.
Mackie, A.S.Y., Oliver, P.G. & Rees, E.I.S. 1995.
Benthic biodiversity in the southern Irish Sea.
Studies in Marine Biodiversity and Systematics
from the National Museum of Wales. BIOMÔR
Reports 1: 263 pp.
Mortimer, K. and Wilson, H. 2009. HABMAP:
Habitat mapping for conservation and
management of the southern Irish Sea
Searchable Data Facility and Resources.
Countryside Council for Wales & Amgueddfa
Cymru — National Museum Wales. DVD-ROM.
Robinson, K. A., Darbyshire, T., Van Landeghem,
K., Lindenbaum, C., McBreen, F., Creaven, S.,
Ramsay, K., Mackie, A.S.Y., Mitchell, N. C.,
Wheeler, A., Wilson, J. G. and O’Beirn, F.
2009a. Habitat mapping for conservation
and management of the southern Irish Sea
(HABMAP). I: Seabed surveys. Studies in
Marine Biodiversity and Systematics from the
National Museum of Wales. BIOMÔR Reports
5(1): 234 pp.
Robinson, K. A., Ramsay, K., Lindenbaum, C.,
Frost, N., Moore, J., Petrey, D. and Darbyshire,
T. 2009b. Habitat mapping for conservation
and management of the southern Irish Sea
(HABMAP). II: Modelling & Mapping. Studies
in Marine Biodiversity and Systematics from
the National Museum of Wales. BIOMÔR Reports
5(2): 210 pp.
Stephen, A. C. & Edmonds, S. J. 1972. The Phyla
Sipuncula and Echiura. The British Museum
(Natural History), London. 528 pp.
Struck, T.H., Schult, N., Kusen, T., Hickman,
E., Bleidorn, C., McHugh, D. and Halanych,
K.M. 2007. Annelid phylogeny and the status
of Sipuncula and Echiura. BMC Evolutionary
Biology 7-57: 11 pp. [www.biomedcentral.
Fig. 4. Distribution of Diplocirrus stopbowitzi,
Uncispio n.sp. and Sericosura conta in the
southern Irish Sea area.
CONFERENCE 2010 — Changing Seas 2
FIELD MEETING 2010 Porcupine Marine Natural History Society Annual Field Meeting 2010
Isles of Scilly 4
Spring field trip 2009 – Plymouth 7
Autumn Field trip 2009 – St. Abbs and Eyemouth VMNR 9
The NMBAQC Scheme – Setting the record straight. Myles O’Reilly (NMBAQC Committee) 15
Some notes on an unusual mollusc, Serpulorbis arenarius (Linné, 1767)
– The giant worm shell Peter Barfield and Evelina Capasso 18
Rediscovery, redescription and resurrection of Metamunna typica Tattersall, 1905 (Peracarida,
Isopoda, Asellota, Paramunnidae). Roger N. Bamber & Roni S. Robbins 21
Notes on new benthic invertebrates from the southern Irish Sea Andrew S.Y. Mackie,
Teresa Darbyshire, Roger N. Bamber & James A. Turner 24
PORCUPINE PROBLEMS - Information Requests and Observations 28
A further note on mass stranding of hyperiid amphipods on northeast beaches.
Frank Evans 28
Reproduction and habitat of the marine alga Padina pavonica (Dictyotales, Phaeophyceae)
in the British Isles. Roger Herbert, Bill Farnham & Ian Tittley 28
Blue-rayed limpets (var. laevis) Jon Moore and Christine Howson 29
The Silent Landscape: In the wake of HMS “Challenger” 1872-1876. Review by Frank Evans 31
A field guide to the marine fishes of Wales and adjacent waters Review by John Lancaster 33
Instructions to Authors 35
Full-text available
A new species of Uncispio Green, 19827. Green , KD. 1982. Uncispionidae, a new polychaete family (Annelida). Proceedings of the Biological Society of Washington, 95: 530–536. View all references is described from a boulder clay habitat in the southern Irish Sea. Uncispio reesi n. sp. can be separated from Uncispio hartmanae Green, 19827. Green , KD. 1982. Uncispionidae, a new polychaete family (Annelida). Proceedings of the Biological Society of Washington, 95: 530–536. View all references by the size and shape of the occipital antenna, the arrangement of the posterior parapodial lobes, the number of anal lobes and the position and shape of thickened anterior neuropodial chaetae. The other two species of Uncispionidae, Uncispio hartmanae and Uncopherusa bifida, are re-examined and their descriptions expanded. The family status of Uncispionidae is discussed with respect to the other families in Spionida.
Full-text available
This report describes the results of a survey of four areas of potential Annex I reef in the Irish Sea, north and west of Anglesey. The survey aimed to improve understanding of the habitats and communities present within areas identified as potentially containing Annex I reef habitat according to the Habitats Directive, and to assess the suitability of these areas for future designation as an offshore SAC. Acoustic and biological survey was undertaken during a survey in 2005. Biological communities were identified and mapped upon the underlying acoustic information. Data was assessed to interpret whether any of the habitats found fit within the interpretation of Annex I reef according to the Habitats Directive. The survey was undertaken as part of two Memorandums of Understanding, the first phase of the project (survey and initial data analysis) was funded through a Memorandum of Agreement between the JNCC, CCW and the UCC. The second phase of the project (further analysis, interpretation and reporting) was funded through a Memorandum of Agreement between the JNCC, CCW and the NMW. Part of the funding for this project was supplied by the MESH project. Cleaning, processing, and interpretation of multibeam bathymetry data was carried out by the University College Cork, under contract to JNCC, and funded by the MESH project. The lead partner for the project was the JNCC.
Full-text available
Surveys of the benthic invertebrates of the southern Irish Sea were carried out in 1989 and 1991. Both quantitative (grab) and qualitative (trawl and dredge) samples were taken for faunal and sediment analysis. The fauna is very rich with some 1030 species recorded. Polychaete worms dominate the fauna followed by the Crustacea and Mollusca. The fauna is not only diverse but is also very abundant, reaching 17,348 individuals per square metre. Many taxonomic problems were encountered, indicating that there remains much basic work to be undertaken. Over twenty polychaete species are possibly new to science and a new species of solenogastre mollusc has already been described. In addition there are many records of species new to British waters as well as to the Irish Sea. The southern Irish Sea can be said to be part of the “Boreal” zoogeographic province but there are also more southern “Lusitanian” influences in the area of the Celtic Deep. Three major faunal assemblages are defined which coincide with general sediment distributions relative to depth. ''Assemblage A" occurred in the deeper mud and sandy mud regions of the Celtic Deep; "Assemblage B" was found in the inshore sandy and muddy sand areas, and "Assemblage C" coincided with the offshore gravelly sediments. The traditional view of fixed communities is not supported here, rather there occurs a mosaic of looser assemblages overlapping in their responses to changing environmental conditions. Species diversity was measured and showed that the gravelly sediments supporting "Assemblage C" were the richest with an average of 145 taxa per station. Diversity indices were calculated and a Shannon- Wiener value of 6.34 is the highest yet recorded from British waters. The high species richness values from the southern Irish Sea compare well with those reported from the very diverse deep-sea benthos. The southern Irish Sea can be regarded as a significant pool of marine biodiversity warranting care and further investigation.
Full-text available
Annelida comprises an ancient and ecologically important animal phylum with over 16,500 described species and members are the dominant macrofauna of the deep sea. Traditionally, two major groups are distinguished: Clitellata (including earthworms, leeches) and "Polychaeta" (mostly marine worms). Recent analyses of molecular data suggest that Annelida may include other taxa once considered separate phyla (i.e., Echiura, and Sipuncula) and that Clitellata are derived annelids, thus rendering "Polychaeta" paraphyletic; however, this contradicts classification schemes of annelids developed from recent analyses of morphological characters. Given that deep-level evolutionary relationships of Annelida are poorly understood, we have analyzed comprehensive datasets based on nuclear and mitochondrial genes, and have applied rigorous testing of alternative hypotheses so that we can move towards the robust reconstruction of annelid history needed to interpret animal body plan evolution. Sipuncula, Echiura, Siboglinidae, and Clitellata are all nested within polychaete annelids according to phylogenetic analyses of three nuclear genes (18S rRNA, 28S rRNA, EF1alpha; 4552 nucleotide positions analyzed) for 81 taxa, and 11 nuclear and mitochondrial genes for 10 taxa (additional: 12S rRNA, 16S rRNA, ATP8, COX1-3, CYTB, NAD6; 11,454 nucleotide positions analyzed). For the first time, these findings are substantiated using approximately unbiased tests and non-scaled bootstrap probability tests that compare alternative hypotheses. For echiurans, the polychaete group Capitellidae is corroborated as the sister taxon; while the exact placement of Sipuncula within Annelida is still uncertain, our analyses suggest an affiliation with terebellimorphs. Siboglinids are in a clade with other sabellimorphs, and clitellates fall within a polychaete clade with aeolosomatids as their possible sister group. None of our analyses support the major polychaete clades reflected in the current classification scheme of annelids, and hypothesis testing significantly rejects monophyly of Scolecida, Palpata, Canalipalpata, and Aciculata. Using multiple genes and explicit hypothesis testing, we show that Echiura, Siboglinidae, and Clitellata are derived annelids with polychaete sister taxa, and that Sipuncula should be included within annelids. The traditional composition of Annelida greatly underestimates the morphological diversity of this group, and inclusion of Sipuncula and Echiura implies that patterns of segmentation within annelids have been evolutionarily labile. Relationships within Annelida based on our analyses of multiple genes challenge the current classification scheme, and some alternative hypotheses are provided.
During analysis of the benthic pycnogonid fauna of the Irish Sea collected by the HABMAP project, a specimen representing an hitherto undescribed species of the genus Sericosura was discovered, representing the shallowest record for the genus, and the first Atlantic record away from oceanic ridges. The new species, Sericosura conta, is more compact than the seven species previously described, and has a much shorter chelifore scape. It is the only species of Sericosura outside the Pacific Ocean to have a nine-articled palp. Three specimens of a second new species, Sericosura hedgpethi, were collected by NIWA from a cold-seep site on the Hikurangi Margin. This New Zealand species has a seven-articled palp, and, uniquely for the genus, is entirely without chelifora. The genus is reviewed, Ammothea verenae is reassigned to Sericosura, and an identification key to males and females of the nine known species is given.
Bag x54001, Durban 4000 (Republic of South Africa) KEY WORDS Echiura, deep-sea fauna, North-East Atlantic, new genus, new species. Biseswar R. 2006. — Additions to the deep-sea echiuran (Echiura) fauna of the North-East Atlantic. Zoosystema 28 (4) : 853-864. ABSTRACT Th is report contains descriptions of 10 species of deep-sea bonelliids from the North-East Atlantic of which three are indeterminate species. Th e specimens were collected during the BENGAL cruises that were undertaken between September 1996 and October 1998 in the Porcupine Abyssal Plain. A new monotypic genus Bengalus n. gen. is erected to accommodate B. longiductus n. gen., n. sp. and another new species, Jakobia densopapillata n. sp., is here described. Th e main distinguishing features of B. longiductus n. gen., n. sp. include the presence of a single, elongated, tubular gonoduct on the right side of the nerve cord with a stalked gonostome located near the distal end of the gonoduct; a thick integu-ment covered with microscopic papillae; tubular anal vesicles and the absence of ventral setae. Jakobia densopapillata n. sp. is distinguished by possessing a thick integument that is densely covered with prominent papillae over the entire surface of the trunk; a truncate proboscis with the lateral margins uniting proximally to form a funnel around the mouth; a single V-shaped gonoduct on the right side of the nerve cord with an anteriorly directed gonostome; tubular anal vesicles and the absence of ventral setae. Th e paper includes the fi rst records of the occurrence of Zenkevitchiola brevirostris Murina, 1978 and Achaetobonellia maculata Fisher, 1953 from the North Atlantic Ocean.
The Irish Sea has long been known to contain extensive areas of shallow gas accumulation, particularly in the area southwest of the Isle of Man. More limited occurrences of seabed features associated with shallow gas migration, such as columnar disturbances, seabed doming and pockmarks, have also been reported. Until now this gas was generally assumed to be of biogenic origin. Recently acquired route survey data have provided new insights into the distribution of both gas accumulation and gas migration in this area, as well as identifying areas of active seepage. It is proposed that the gas originates as coalbed methane or thermogenic gas in the extensive Carboniferous deposits underlying this region. This has considerable significance for hydrocarbon exploration in this area. -Author
The HABMAP project aimed to provide seabed habitat maps that could be used for conservation and management. The project was carried out in the southern area of the Irish Sea and northeastern part of the adjoining Celtic Sea. It was a partnership between several organisations in Wales and Ireland, partly funded by the INTERREG IIIa European Regional Development Fund for cross border projects between Wales and Ireland. There were two main components to the project; collection of new survey data and mapping seabed habitats using data collation and predictive modelling. This volume of the report describes the survey work undertaken by the HABMAP project. Volume 2 of the report (Robinson et al. 2009) describes the predictive modelling work. Surveys using multibeam swath bathymetry, drop-down video, grab sampling and sediment profile imagery (SPI) were carried out in the summer of 2005. The areas surveyed were off Arklow, the Celtic Deep, Caernarfon Bay and two smaller areas off Cardigan Bay (in St George’s Channel). A further area to the west of Anglesey was also visited for the collection of sediment and faunal samples. The purpose of the survey work was two-fold: 1. to increase our knowledge of Irish Sea habitats 2. to collect data on a wide range of different habitats that could be used to validate the outputs of predictive modelling work (the results of which are presented in Volume 2 of this report (Robinson et al. 2009)). A variety of different seabed features and biotopes (the seabed habitat and its associated organisms) were recorded from each of the survey areas. Results from the Arklow survey area showed that a combination of relict and relatively modern seabed features were present. The strong tidal currents and coarse nature of the seabed in this area often made sampling with grabs and video equipment difficult. Faunal communities generally reflected these conditions, with coarse sediment and tide-swept communities being frequently recorded. Key features of the area included a deep trough to the north, and a rich blue mussel (Mytilus edulis) bed to the west of the trough. Data collected from the Celtic Deep survey area coincided with a known transition from mud in the Celtic Deep to coarser sediments in St George’s Channel (Tappin et al. 1994). Results reflected this transition, with grab samples and video tows showing that sediments were composed of mud in the south, progressing to coarse sediment in the north. Multibeam Echosounder (MBES) data from the area reflected this change in substrate type, with backscatter intensities increasing from south to north. Similar changes were noted in the benthic community, with muddy biotopes being recorded in the south, progressing to coarse and mixed sediment biotopes in the north. Two areas were surveyed in the St George’s Channel area (north and south), both of which were found to have similar sediment types, benthic communities and bedforms. They were characterised by mostly coarse or mixed sediments, with biotopes reflecting these. Of key interest in the two areas were a number of straight-crested ridge features noted on multibeam bathymetry data, with adjacent deep scour marks. Further investigation of these features using video tows, SPI and grabs showed their surfaces were composed of relatively coarse, mobile sand. It was thought that the ridges were derived from relict features, though were still playing an active role in characterising the benthic environment. Survey work carried out in Caernarfon Bay showed this area was very diverse in terms of both its seabed features and benthic communities. The location of a well-documented horse mussel (Modiolus modiolus) reef was clearly identified from multibeam bathymetry and backscatter data, and was sampled using video, SPI and grab samples. The area was rich in both infauna and epifauna, with a variety of different biotopes being recorded. Other features of the Caernarfon Bay survey area included an area of cobble and boulder ridges in the southwest with associated tide-swept epifaunal communities, and an area of muddy sediments in shallower waters to the east, with patches of stable cobbles that supported a rich seaweed and epifaunal community. Additional sampling work was also carried out in an area off the west coast of Anglesey, known to be associated with deep troughs. Unfortunately, no multibeam acoustic data was collected from this region, though video, SPI and grab samples were obtained. These showed that the sediments and habitats in the region were quite varied, with boulder clay being present in the southwestern part of the area. The boulder clay was found to support a rich benthic community that did not conform to any of the currently described sublittoral biotopes, and was dominated by a polychaete species that had not previously been recorded in UK or Irish waters. The results from the HABMAP survey work were used to validate outputs from predictive biotope modelling and mapping work carried out as part of the wider project, as presented in Volume 2 of this report (Robinson et al. 2009). Datasets arising from the HABMAP survey work are located on the Appendices DVD-ROM that accompanies this report.