ALCATEL SUBMARINE NETWORK Havhingsten Appendix I3- Benthic Characterisation Report - Ireland P2228_R4693_Rev0 App I3| June 2019 Intertek Energy & Water Consultancy Services Exchange House, Station Road, Liphook, Hampshire GU30 7DW, United Kingdom Benthic Characterisation Report Havhingsten Cable Route Ireland Fugro Document No.: 181275-R-015(02) 4 July 2019 Alcatel Submarine Networks UK Limited Final report Fugro Document No. 181275-R-015(02) Page 1 of 63 Benthic Characterisation Report Havhingsten Cable Route Ireland Fugro Document No.: 181275-R-015(02) 4 July 2019 Final report Prepared by: Fugro GB Marine Limited Trafalgar Wharf, Unit 16, Hamilton Road Portchester, Portsmouth, PO6 4PX United Kingdom T +44 (0)2392 205 500 www.fugro.com Prepared for: Alcatel Submarine Networks UK Limited Telegraph House 10 Telecon Way Greenwich London SE10 0AG United Kingdom G. Harris-Bryant S. Brittain 02 Final report D. McLaren L. Bush C. Barrett 4 July 2019 J. Lusted J. Hunt G. Harris-Bryant S. Brittain 01 Draft report D. McLaren L. Bush C. Barrett 23 May 2019 J. Lusted J. Hunt Issue Document Status Prepared Checked Approved Date Fugro GB Marine Limited. Registered in England No. 1135456. VAT No. GB 579 3459 84 A member of the Fugro Group of Companies with offices throughout the world Fugro Document No. 181275-R-015(02) ALCATEL SUBMARINE NETWORKS UK LIMITED HAVHINGSTEN CABLE ROUTE, IRELAND BENTHIC CHARACTERISATION REPORT FRONTISPIECE Fugro Document No. 181275-R-015(02) Page i of ix ALCATEL SUBMARINE NETWORKS UK LIMITED HAVHINGSTEN CABLE ROUTE, IRELAND BENTHIC CHARACTERISATION REPORT EXECUTIVE SUMMARY Introduction On the instruction of Alcatel Submarine Networks UK Limited, Fugro performed a benthic characterisation survey for the installation of a telecommunications cable along the Irish section of the proposed Havhingsten cable route. The offshore survey was conducted using the RV Prince Madog during the survey period 23 to 24 February 2019. The nearshore survey was conducted using the MV Fastnet Petrel during the period 21 to 22 March 2019. The benthic characterisation survey was conducted to establish the presence of any sensitive habitats or species within the cable route corridor, specifically habitats listed under Annex I of the European Commission (EC) Habitats Directive and habitats or species considered threatened and/or declining under the Oslo-Paris (OSPAR) convention (OSPAR, 2008). Grab samples were also collected to establish physico-chemical and biological properties of the sediment. Survey Strategy A total of six environmental stations were selected along the Irish section of the Havhingsten cable route. At each of these stations, drop-down camera was undertaken prior to grab sampling. Sediment Characterisation The sediments within the Irish section of the Havhingsten cable route demonstrated moderate variability in mean diameter and low to high variability for the proportions of sand, gravel and fines, indicating the presence of varied sediments. Using the Wentworth description, sediments varied from fine sand to coarse silt across the survey area. Sediment Chemistry The gas chromatographic profiles shared a common underlying hydrocarbon distribution, characterised by a ‘hump’ of unresolved material (UCM) peaking late in the chromatogram window and a range of low-level resolved n-alkanes. Variation in total hydrocarbon content (THC) concentrations was moderate (RSD 43 %). Higher concentrations of THC were generally found at stations with a greater total organic matter content. The total 2 to 6 ring polycyclic aromatic hydrocarbon (PAH) concentrations across the survey area were below the effects range low (ERL) value. The United States Environmental Protection Agency 16 (US EPA 16) PAH concentrations were below their respective effects range low (ERL) values at all stations. When normalised to 2.5 % total organic carbon (TOC), the US EPA 16 PAH concentrations (individual and total) exceeded background assessment concentration (BAC) values, for naphthalene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene and benzo(a)pyrene at all stations and benzo(ghi)perylene at one station. However, TOC levels were low and may lead to overestimation of normalised PAH values. Variability of metals concentrations across the survey area ranged from low to moderate (≤ 47 %), with the highest variability observed for aluminium. All metals concentrations were below their respective ERL value. Fugro Document No. 181275-R-015(02) Page ii of ix ALCATEL SUBMARINE NETWORKS UK LIMITED HAVHINGSTEN CABLE ROUTE, IRELAND BENTHIC CHARACTERISATION REPORT Macrofauna There was a low to moderate degree of infaunal similarity between the stations sampled. The most nearshore of the stations sampled a community dominated by the bivalve mollusc Abra alba. Slightly further offshore, a diverse and densely populated community characterised by the brittlestar Amphiura filiformis and bivalve Kurtiella bidentata was identified. The stations located along the offshore, easterly end of the route were shown to have variably rich communities of bivalves and polychaetes. Benthic Habitats and Biotopes Two European Nature Information System (EUNIS) biotopes and two biotope complexes were recorded along the route. One biotope complex was associated with bedrock and/or boulder habitat adjacent to Loughshinny Bay and the remainder were sediment biotopes/biotope complexes. Due to the occurrence of sea pens and faunal burrows on the offshore section of the route, these were assessed to determine their resemblance to the OSPAR threatened and/or declining habitat ‘sea pens and burrowing megafauna communities’. None of the stations/transects assessed were thought to strongly resemble this priority habitat. Boulder and/or cobble substrata identified adjacent to Loughshinny Bay (station LS_ST01) were assessed to determine their resemblance to ‘stony reef’ habitat listed under Annex I of the EC Habitats Directive. While the results of this assessment suggested that these areas only demonstrated a ‘low’ level of resemblance to this priority habitat, bedrock substrata, which could be considered Annex I ‘bedrock reef’, were also thought to be present in this area. There are currently no guidelines available for the assessment of the potential conservation importance of ‘bedrock reef’ habitats. No other OSPAR threatened and/or declining species and habitats, Annex I habitats or Annex II species were observed within the survey area. Fugro Document No. 181275-R-015(02) Page iii of ix ALCATEL SUBMARINE NETWORKS UK LIMITED HAVHINGSTEN CABLE ROUTE, IRELAND BENTHIC CHARACTERISATION REPORT CONTENTS 1. INTRODUCTION 1 1.1 Background 1 1.2 Scope of Work 1 1.3 Environmental Legislation 1 1.4 Protected Sites and Potentially Sensitive Habitats 2 1.5 Regional Standards for Sediment Chemical Concentrations 6 1.6 Coordinate Reference System 6 2. ENVIRONMENTAL SURVEY METHODS 7 2.1 Survey Strategy 7 2.2 Survey Methods 7 2.2.1 Sediment Grab Sampling 7 2.2.2 Seabed Video/Photography 8 2.3 Analytical Strategy 8 3. FIELD OPERATIONS 9 3.1 Seabed Sampling 9 3.2 Seabed Video/Photography 9 4. SEDIMENT CHARACTERISATION 12 4.1 Introduction 12 4.2 Results 12 5. SEDIMENT CHEMISTRY 17 5.1 Introduction 17 5.2 Sediment Hydrocarbons 17 5.2.1 Gas Chromatography–Flame Ionisation Detection (GC-FID) Hydrocarbon Profiles 17 5.2.2 Total Hydrocarbon and n-Alkane (nC12 to nC36) Content 18 5.2.3 Sediment Aromatic Hydrocarbon Content 19 5.3 Sediment Metals 20 6. SEDIMENT MACROFAUNA 23 6.1 Introduction 23 6.2 Results 23 6.2.1 Investigation of Faunal Similarities 23 6.2.2 Phyletic Composition 25 6.2.3 Characteristic Taxa 28 6.2.4 Community Statistics 29 7. BENTHIC HABITATS AND BIOTOPES 32 7.1 Introduction 32 7.1.1 Seabed Habitats Classification 32 7.1.2 Sensitive Habitats and Species Assessments 32 7.2 Results 34 Fugro Document No. 181275-R-015(02) Page iv of ix ALCATEL SUBMARINE NETWORKS UK LIMITED HAVHINGSTEN CABLE ROUTE, IRELAND BENTHIC CHARACTERISATION REPORT 7.2.1 Benthic Habitat and Biotope Classification 34 7.2.2 Biotope Descriptions 36 7.2.3 Potentially Sensitive Habitats and Species 41 8. DISCUSSION 47 8.1 Introduction 47 8.2 Sediment Characterisation 47 8.3 Sediment Chemistry 48 8.3.1 Total and Aliphatic Hydrocarbons 48 8.3.2 Aromatic Hydrocarbons 49 8.3.3 Heavy and Trace Metals 50 8.4 Macrofaunal Communities 51 8.5 Seabed Habitats and Biotopes 52 9. CONCLUSIONS 55 10. REFERENCES 57 APPENDICES A. GUIDELINES ON USE OF REPORT B. METHODOLOGIES B.1 SURVEY B.2 LABORATORY ANALYSIS B.3 STATISTICAL ANALYSIS C. LOGS C.1 SURVEY LOG C.2 GRAB LOG C.3 VIDEO AND PHOTOGRAPHIC LOG D. SEDIMENT PARTICLE SIZE E. SEDIMENT CHEMISTRY E.1 GAS CHROMATOGRAPHY TRACES E.2 INDIVIDUAL N-ALKANE CONCENTRATIONS E.3 US EPA 16 PAH CONCNETRATIONS E.4 TOTAL 2 TO 6 RING PAH CONCENTRATIONS E.5 DISTRIBUTION OF AROMATIC HYDROCARBONS E.6 5 % ALUMINIUM-NORMALISED HEAVY AND TRACE METAL CONCENTRATIONS Fugro Document No. 181275-R-015(02) Page v of ix ALCATEL SUBMARINE NETWORKS UK LIMITED HAVHINGSTEN CABLE ROUTE, IRELAND BENTHIC CHARACTERISATION REPORT F. MACROFAUNAL ANALYSIS G. SEABED PHOTOGRAPHS H. SENSITIVE HABITAT ASSESSMENT H.1 STONY REEF ASSESSMENT TABLES IN THE MAIN TEXT Table 1.1: Relevant Sensitive Habitats, Havhingsten Cable Route, Ireland 4 Table 1.2: Project Geodetic and Projection Parameters 6 Table 2.1: Proposed Environmental Stations, Havhingsten Cable Route, Ireland 7 Table 3.1: Completed Environmental Survey Sampling Stations, Havhingsten Cable Route, Ireland 9 Table 3.2: Completed Environmental Survey Camera Transects,