Page 383 - Alderney Regional Environmental Assessment of Renewable Energy: Environmental Report

Alderney Regional Environmental Assessment of Renewable Energy:
Environmental Report
Appendix B. Biotopes Recorded Around Alderney
Table B1. Seasearch biotopes and features of interest recorded around Alderney
Site Area Habitat Community Types Features of Interest Main Biotopes
1a Longis Bay and
Raz Island
Fine sand (up to
7.5m depth)
Extensive eelgrass beds
cover most of the entrance to
the Bay (3-7.5m)
Burrowing worms and
anemones, and two- spot
gobies Gobiosculus
flavescens, were abundant.
46 species of seaweeds were
present, including the
peacock’s tail, Padina
pavonica, which is very
scarce in British waters
IR.MIR.KR.Lhyp Laminaria
hyperborea and foliose red
seaweeds on moderately
exposed infralittoral rock
SS.SSa.IFiSa infralittoral fine
sand
SS.SMp.SSgr.Zmar Zostera
marina/angustifolia beds on
lower shore or infralittoral
clean or muddy sand
Rocky slopes and
ridges
Two species of forest kelps,
the widespread cuvie
Laminaria hyperborea, and
the southerly golden kelp
Laminaria ochroleuca.
A small amount of the
invasive japweed Sargassum
muticum was present but it
did not appear to be
becoming dominant
Rich understorey of red
seaweeds, and an extensive
mixed algal community were
present in the more sheltered
rocky areas
2a Baie du Grounard Steep sided rocky
reefs
Most surfaces were seaweed
dominated with thongweed
Himanthalia elongata on
upper surfaces, and
occasional kelps, cuvie L.
hypberborea and furbelows
Saccorhiza polyschides.
Notable at this site were
scour tolerant anemones,
daisy anemone, Cereus
pedunculatus and gem
anemone, Aulactinia
verrucosa
LR.HLR.FR.Him Himanthalia
elongata and red seaweeds
on exposed to moderately
exposed lower eulittoral rock
Vertical and
overhanging rock
faces
Encrusting coralline algae
and a short animal turf
consisting mainly of
bryozoans and sea squirts.
3a St Esquere Bay Medium to large
boulders on
bedrock (9-10m
depth)
Kelp forest and a dense
understorey of foliose and
filamentous red seaweeds
The more shallow habitats
were notable for the lack of
fauna, either sessile or
mobile and whilst there was a
little more animal life present
in the deeper habitat it was
still relatively impoverished.
IR.HIR.KFaR.LhypR
Laminaria hyperborea with
dense foliose red seaweeds
on exposed
infralittoral rock
IR.HIR.KFaR.LhypR.Loch
Mixed Laminaria hyperborea
and Laminaria ochroleuca
forest on exposed infralittoral
rock
Flat cobble and
pebble seabed (9-
12m)
Kelp park of Laminaria
ochroleuca and an
understorey of red seaweeds
Larger boulders
(11-13m)
Kelp cover and an
understorey of dense oaten
pipes hydroid, Tubularia
indivisa, a typical inhabitant
of current swept areas
4a Cats Bay, Quenard
Point and Fort
Homeaux Florains
Rocky margins Seaweed dominated, with
large brown seaweeds,
thongweed Himanthalia
elongata, furbelows
Saccorhiza polyschides and
cuvie Laminaria hyperborea
all dominating different areas
and always with an
understorey of other mixed
red and brown seaweeds.
55 species of seaweed
recorded Two very
characteristic Channel lsland
species were present, the
ormer Haliotis tuberculata
and the black face blenny
Tripterygion deleasi. The
ormer does not occur on the
north side of the English
Channel and the black face
blenny has a restricted
distribution from Dorset to the
south coast of Cornwall.
IR.HIR.KFaR.LhypR.Loch
Mixed Laminaria hyperborea
and Laminaria ochroleuca
forest on exposed infralittoral
rock
IR.MIR.KR.Lhyp Laminaria
hyperborea and foliose red
seaweeds on moderately
exposed infralittoral rock
IR.FIR.IFou Infralittoral
fouling seaweed communities
SS.SSa.IFiSa.IMoSa
infralittoral mobile clean sand
with sparse fauna
Gully bottoms were
filled with boulders
or cobbles
Dominated by green
seaweeds, limited fauna on
the steeper gully sides
Tide-swept rocks Kelp forest of golden kelp
Laminaria orchroleuca below
10m, becoming kelp park with
pod weed, Halidrys siliquosa
also common.
R/4001/7 B.1 R.2129