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 January 2013 (unpublished).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 .....................................................................................................