Marine biological survey to establish the distribution and status of ...

3 RESULTS
Successful drop-down video recordings were made as a series of drifts over the seabed at
63 shallow water stations (of which seven stations were established specifically looking for
maerl - these were completed during the deeper video component of the sampling) and 60
deep water stations. The sampling locations are illustrated in Figures 6, 7 and 8. Positional
information and summary notes for each video sample (including biotope assignments and
alignment with MPA search features / PMFs) are provided in Tables A1.1 and A1.2
(Appendix 1). The species recorded during the two phases of the video work are tabulated
in Tables A1.5 and A1.6 for the shallow water and deep water stations respectively (all
tables within Appendix 1).
The distribution of the grab stations is illustrated in Figure 9 and the detailed infaunal
analyses are provided in Appendix 2.
The 15 dive locations are illustrated in Figure 10 and detailed in Table A1.3. Habitat
descriptions from the dive sites are given in Table A1.4 and the species recorded during the
diving work are tabulated in Table A1.7 (all tables within Appendix 1). The detailed results of
the infaunal survey of the seagrass beds are included in Appendix 3.
Logs of photographs and video footage collected during the 2010 survey are included in
Appendix 4.
3.1 Biotope composition and distribution within the Sound of Canna
The 52 biotopes recorded during the survey in 2010 are listed in Table 2 (overleaf). Two of
the MPA search features recorded within the Sound of Canna in 2010 are not classified as
discrete biotopes within the current version of the national biotope classification (Connor et
al., 2004). For the purposes of this report, the following provisional biotopes have been
assigned to the northern featherstar and fan mussel aggregation search features
respectively:
Aggregations of the northern feather star Leptometra celtica on mixed muddy
sediments (SS.SMu.CSaMu.Lcelt); and
Aggregations of the fan mussel Atrina fragilis in poorly sorted mixed muddy
sediments (SS.SBR.SMus.Afrag).
Figures 11 and 12 show the distribution of all of the stations sampled in 2010, coded at the
biotope complex level (colouring aligns with Table 2).
Infralittoral kelp biotopes were restricted to suitable habitat along the coastal margins on
either side of the sound, primarily within the 20 m depth contour (with Laminaria hyberborea
kelp forests IR.HIR.KFaR.LhypFa and IR.HIR.KFaR.LhypR recorded to ~18.5 m and
individual kelp plants down to ~24 m). The kelp with cushion fauna and/or foliose red
seaweeds (IR.HIR.KFaR) and sediment-affected or disturbed kelp and seaweed
communities (IR.HIR.KSed) biotope complexes were present on the more exposed, high
energy areas of coastline to the south and west of Canna and Sanday and along the west
coast of Rum. The moderate and low energy kelp dominated biotope complexes
(IR.MIR.KR and IR.LIR.K) were restricted to shallower water or areas afforded protection
from wave action by virtue of geographical aspect (e.g. north-east of Sanday), nearshore
rocks or within small embayments. In the lower infralittoral, in areas of high energy below
the kelp zone, foliose red seaweeds were present on bedrock and mixed boulder and cobble
substrates (IR.HIR.KFaR.FoR).
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