Appendix O: Ecology: Benthic Appendix O.1: Benthic Survey Fugro Invergordon Ground Investigation Benthic Report Pre-Construction Benthic Survey Cromarty Firth Fugro Document No.: 160868_01rev1 06 April 2017 Fugro Geoservices Fugro Document No. 160868_01rev1 Page 1 of 39 FUGRO GEOSERVICES INVERGORDON GROUND INVESTIGATION BENTHIC REPORT PRE-CONSTRUCTION BENTHIC SURVEY Invergordon Ground Investigation Benthic Report Pre-Construction Benthic Survey Cromarty Firth 24 to 25 February 2017 Fugro Document No.: 160868_01rev1 Volume 1 of 1 Prepared for: Fugro Geoservices Bickland Industrial Park Falmouth Cornwall TR11 4TA United Kingdom 01 Draft E. Capasso S. De Gregorio J. Greig 06 April 2017 Issue Report Status Prepared Checked Approved Date Fugro Document No. 160868_01rev1 FUGRO GEOSERVICES INVERGORDON GROUND INVESTIGATION BENTHIC REPORT PRE-CONSTRUCTION BENTHIC SURVEY EXECUTIVE SUMMARY The Port of Cromarty Firth required to undertake a pre-construction benthic survey of the Phase 4 area (Berth 6 and 7) of the Invergordon Service Base. The aim of the survey was to gain a better understanding of the benthic environment within the proposed development area. The survey comprised seabed video transects, covering the length and width of the development area, and grab sampling at seven stations within the area. All samples were collected successfully. Analysis of the video footage showed the presence of one habitat within the survey area, characterised by highly heterogeneous seabed sediment, comprising a mix of mud and sand with gravel and shells, including pebbles and cobbles. The epibenthic communities reflected this sediment complexity, with sessile epifauna ranging from abundant to common in areas with high percentage of hard substrate, and less so in sandier areas, which, consequently, showed less diverse communities. The epibenthic communities recorded by the seabed video footage included taxa from each major taxonomic group and were broadly comparable to those reported for the shallower sediment areas of the Cromarty Firth and similar coastal areas of the North Sea. Taxa encountered included Laminaria sp. (kelp), the common starfish Asterias rubens, the brittlestar Ophiura albida and the edible-sea-urchin Echinus esculentus. The polychaete Spirobranchus sp. was also common and the molluscs recorded included mainly unidentified gastropods and the blue mussel Mytilus edulis. Crustacea recorded included the hermit crab Pagurus bernhardus and the common shore crab Carcinus maenas. The plumose anemone Metridium dianthus and the anthozoan Alcyonium digitatum were recorded within the survey area as well as turf forming species which included Hydroid/Bryozoan taxa, which were not possible to identify at a lower taxonomic level. Fragments of Lithothamnion sp. (maerl) were also present along each transect, and the only two fish taxa encountered included the European plaice Pleuronectes platessa and the dragonet Callionymus sp. The sediment data included field description of the grab samples only, as no grab samples for sediment particle size analysis were collected during this survey. The results of the video analysis and photographic records were also used to support the assessment. All samples were described as gravelly muddy sand (gmS) with shells and shell fragments; the shells were mainly Mytilus edulis and at one grab site also oyster shells were identified. The video analysis showed that the surface of the seabed appeared as coarse mixed sediment gravelly, muddy sand, with varying amounts of shells, pebbles and cobbles. Results of the biological analyses indicated that, in terms of species diversity, most stations hosted a moderately rich community, whilst few stations were characterised by a less diverse community. In terms of abundances (i.e. total number of individuals per stations), these were generally high and related to infaunal taxa such as Nematoda, Pholoe inornata and Scoloplos (Scoloplos) armiger. To the higher species diversity and, particularly, abundances contributed the presence of epibenthic species (e.g. the ascidian Dendrodoa grossularia and the polychaete Spirobranchus lamarki) that, with the presence of more heterogeneous sediment including large fraction of shells and shell fragments, finds hard substrate suitable for the settlement. This sediment type is also suitable for the attachment of kelp species (Laminaria sp.) which in turn provide suitable habitat for a number of epibenthic species. The observed biological diversity and distribution, together with granulometry, are typical of the shallow depth areas of the North Sea. This is in line with the literature which refers to bathymetry and sediment type as being the major physical variables affecting macrofaunal occurrence and distribution in the North Sea. Fugro Document No. 160868_01rev1 Page i of vi FUGRO GEOSERVICES INVERGORDON GROUND INVESTIGATION BENTHIC REPORT PRE-CONSTRUCTION BENTHIC SURVEY Sessile, non-enumerated taxa recorded from the grab samples were largely represented by organisms belonging to the phylum Bryozoa, which was the more diverse. These included Escharoides coccinea, Schizoporella sp., Fenestrulina malusii, Celleporella hyalina, Membranipora membranacea, Conopeum reticulum, Electra pilosa, and Amphiblestrum auritum. The multivariate analysis was run excluding the juvenile taxa. Results highlighted the presence of three major benthic groups, however these were not considered to represent ecologically different communities, but rather variation of the same community. The main differences observed were related to differences in the average abundance of the same species, with differences in community composition being small by comparison. The group which encompassed the higher number of samples (group B) was characterised by a heterogeneous sandy sediment, hosting overall higher faunal richness and diversity, with fauna typical of communities adapted to withstand physical disturbance, such as crustacean amphipods and polychaete worms including P. inornata and S. armiger, as well as Abra alba and Mediomastus fragilis, which are typical of habitats with a certain degree of compactness and hence stability. Group A included the two samples from the two shallowest stations, described as gravelly muddy sand and characterised by the presence of boulders and pebbles. The fauna characterising the group was similar to the fauna of the other groups, but with a higher mean abundance of sessile species such as D. grossularia and S. lamarki. Group C encompassed samples from the three least diverse stations, with the sediment described as coarse mixed sediment where pebbles and cobbles were also present. These stations were also located along the existing sea wall of the port. The top three, most abundant, taxa included Nematoda and the polychaetes S. lamarki and S. armiger. Phylum Nemertea and the ascidian D. grossularia were also common within this group, although the abundances of the individual taxa were lower compared to the abundances of the same taxa within other groups. Within this group, station ST01 was characterised by the presence of the polychaete Phyllodoce mucosa, which occurred at particularly high abundance. This species is known to occur mainly on intertidal sand and mud but also at depths of up to 20 m, on seabed sediments comprising of stones and shell gravel. Thirty-two newly settled juveniles were recorded, largely represented by species of Mytilidae which occurred at all stations. The phylum Mollusca was the most diverse and numerically dominant in terms of juveniles, with species such as Mya sp. juv., Lucinoma borealis juv., Nuculidae juv. and Trochidae juv. being mostly represented. Of the Echinodermata, the family Ophiuroidea was the most abundant, followed by Echinoidea juv. and Cucumariidae juv. The remaining taxa belonged to the phyla ‘Annelida’, with species such as Polynoidae juv., Nephtyidae juv. and Arenicolidae juv. Juvenile ‘Crustacea’, included Ampelisca sp. juv., Paguridae juv., Carcinus maenas juv. and Atelecyclus rotundatus juv., ‘Echinodermata’, including Echinoidea juv. Cucumariidae juv., ‘Mollusca’, including Mya sp. juv., Lucinoma borealis juv., Nuculidae juv. Trochidae juv. and ‘Others’, including Ascidiacea juv. and Sipuncula juv. Using video and grab data, the biotope complex SS.SMX.IMx (Infralittoral mixed sediment) was identified as the most widespread across the survey area, together with the biotope complex SS.SSA.IMuSa (Infralittoral muddy sand), the latter being more localised. No species or habitats of conservation importance, nor non-indigenous species, were found within the survey area. Fugro Document No. 160868_01rev1 Page ii of vi FUGRO GEOSERVICES INVERGORDON GROUND INVESTIGATION BENTHIC REPORT PRE-CONSTRUCTION BENTHIC SURVEY CONTENTS 1. INTRODUCTION 1 1.1 Study Background 1 1.2 Environmental Context 1 1.3 Benthic Habitats and Communities 2 2. METHODOLOGIES 4 2.1 Survey Design 4 2.2 Sampling Survey 4 2.2.1 Seabed Drop-down Video (DDV) Footage and Photographic Stills Sampling 4 2.2.2 Sediment Grab Sampling for Macrofauna 4 3. SAMPLE ANALYSIS 6 3.1 Seabed Video Footage and Photographic Stills Analysis 6 3.2 Laboratory Analysis 6 3.2.1 Grab Macrofauna Abundance 6 4. DATA ANALYSES 7 4.1 Sediment Data 7 4.2 Macrofauna Data Analysis 7 4.2.1 Univariate Analysis 7 4.2.2 Multivariate Analysis 8 4.3 Biotope Classification 9 4.4 Habitats and Species of Nature Conservation Interest 9 5. RESULTS 10 5.1 Seabed Video Footage and Photographic Stills Analysis 10 5.2 Sediment Data 11 5.3 Macrofauna Data Analysis