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Argyll Array Windfarm Basking Shark Draft Chapter for Environmental Statement

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Argyll Array Windfarm Basking Shark Draft Chapter for Environmental Statement ARGYLL ARRAY WINDFARM BASKING SHARK DRAFT CHAPTER FOR ENVIRONMENTAL STATEMENT CORMAC BOOTH, STEPHANIE KING AND CLAIRE LACEY 07 January 2013 Report Code: SMRUL-WSP-2013-001 This report includes contributions from APEM Ltd: Victoria Alle, Heather Webb, Dr Christopher Cesar and Mark Jowett This report is to be cited as: Booth, C.G., King, S.L. & Lacey, C. (2013). “Argyll Array Wind farm Basking Draft Chapter for Environmental Statement”. SMRU Ltd report number SMRUL-WSP-2013- 001. January 2013 (unpublished). Approved by: Cormac Booth, Project Manager 1 CONTENTS 1 Introduction ................................................................................................................................ 6 2 Ecology & Conservation status ................................................................................................... 7 2.1 Geographic distribution .......................................................................................................... 7 2.2 Conservation status ................................................................................................................ 7 2.3 Feeding, foraging and diet ...................................................................................................... 8 2.4 Reproduction .......................................................................................................................... 9 2.5 Legislation ............................................................................................................................. 10 3 Site specific review of existing data/information ..................................................................... 10 3.1 Visual surveys of basking sharks – a cautionery note ........................................................... 10 3.2 Location and usage of sites in Scotland by basking sharks (Nicholson et al. 2000) .............. 11 3.2.1 Overview ........................................................................................................................... 11 3.3 Scottish National Heritage West Scotland basking shark survey (Speedie et al. 2009)........ 12 3.3.1 Introduction and methodology ......................................................................................... 12 3.3.1 Results ............................................................................................................................... 13 3.4 Marine Conservation Society: Basking shark watch reports ................................................ 15 3.4.1 Introduction ...................................................................................................................... 15 3.4.2 Results ............................................................................................................................... 15 3.5 Community Sightings Programme (Hebridean Whale and Dolphin Trust 2011) .................. 16 3.5.1 Introduction .......................................................................................................................... 16 3.5.2 Basking shark sightings ......................................................................................................... 17 3.6 Current research ................................................................................................................... 18 3.6.1 Scottish Natural Heritage and University of Exeter tagging study ....................................... 18 3.6.2 University of Aberdeen Genetics work (Reviewed in Drewery 2012) .............................. 18 3.6.3 Plymouth Marine Laboratory & Marine Biological Association (reviewed in Drewery 2012) 18 4 Review of Argyll Array Survey Data .......................................................................................... 18 2 4.1 Introduction .......................................................................................................................... 18 4.2 Survey methodology ............................................................................................................. 20 4.3 Data analysis ......................................................................................................................... 21 4.3.1 Investigating basking shark key environmental factors .................................................... 21 4.3.1.1 Statistical analysis ......................................................................................................... 21 4.3.1.2 Sources of covariate data .............................................................................................. 22 4.3.1.3 Investigating collinearity ............................................................................................... 23 4.3.1.4 Model Selection ............................................................................................................. 24 4.3.2 Argyll Array basking shark abundance estimation ............................................................ 24 4.3.2.1 Distance at detection .................................................................................................... 24 4.3.2.2 Detection function ......................................................................................................... 25 4.4 Visual survey Results ............................................................................................................. 26 4.4.1 Basking shark encounter rates .......................................................................................... 26 4.4.2 Basking shark size and group size ..................................................................................... 29 4.4.3 Basking shark key environmental factors ......................................................................... 29 Spatial distribution of basking sharks ............................................................................................ 31 4.4.4 Argyll Array basking shark abundance estimation ............................................................ 31 4.4.5 Review and identification of potential limitations of the Argyll Array survey data.......... 32 4.4.5.1 Temporal coverage ....................................................................................................... 32 5 Impact assessment .................................................................................................................... 33 5.1 Assessment methodology ..................................................................................................... 33 5.1.1 Impact scores .................................................................................................................... 34 5.1.1.1 Legislative sensitivity index ........................................................................................... 34 5.1.1.2 Population Status Sensitivity Index ............................................................................... 36 5.1.1.3 Severity of effect ........................................................................................................... 37 5.1.1.4 proportion of population affected ................................................................................ 38 5.1.1.5 Assessing Impact scores ................................................................................................ 39 3 5.1.2 Certainty ............................................................................................................................ 40 5.1.3 Example: Basking shark- Collision – Increased vessel presence ........................................ 40 5.2 Impact scores for Argyll Array wind farm ............................................................................. 42 5.2.1 Construction phase ........................................................................................................... 43 5.2.1.1 increased vessel activity – Collision Risk & Disturbance ............................................... 43 Assessment of Significance ............................................................................................................ 44 Mitigation ...................................................................................................................................... 44 5.2.1.2 Non-toxic contamination – Increase in suspended sediment ....................................... 44 Assessment of Significance ............................................................................................................ 45 5.2.1.3 Increased anthropogenic noise & vibration: Overview ................................................. 45 Increased anthropogenic noise & vibration: Piling........................................................................ 46 Increased anthropogenic noise & vibration: Vessel noise............................................................. 46 Assessment of Significance ............................................................................................................ 46 Mitigation ...................................................................................................................................... 47 5.2.1.4 Entanglement: Interaction with infrastructure (inter-array & export cabling) ............. 47 Assessment of Significance ............................................................................................................ 47 5.2.2 Operation phase................................................................................................................ 48 5.2.2.1 Presence of turbines .....................................................................................................
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