The Sizewell C Project 6.3 Volume 2 Main Development Site Chapter 22 Marine Ecology and Fisheries Appendix 22C - Sizewell Benthic Ecology Characterisation Revision: 1.0 Applicable Regulation: Regulation 5(2)(a) PINS Reference Number: EN010012 May 2020 Planning Act 2008 Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations 2009 Sizewell benthic ecology characterisation TR348 Sizewell benthic ecology NOT PROTECTIVELY MARKED Page 1 of 122 characterisation TR348 Sizewell benthic ecology NOT PROTECTIVELY MARKED Page 2 of 122 characterisation Table of contents Executive summary ................................................................................................................................. 10 1 Context ............................................................................................................................................... 13 1.1 Purpose of the report................................................................................................................ 13 1.2 Thematic coverage ................................................................................................................... 13 1.3 Geographic coverage ............................................................................................................... 14 1.4 Data and information sources ................................................................................................... 17 1.4.1 BEEMS intertidal survey .................................................................................................. 17 1.4.2 BEEMS subtidal surveys ................................................................................................. 17 1.4.3 The wider marine environment ........................................................................................ 20 2 Overview of the features of interest onshore ................................................................................... 21 2.1 Intertidal benthic assemblages ................................................................................................. 21 2.2 Coastal saline lagoons ............................................................................................................. 22 2.3 Coastal vegetated shingle ........................................................................................................ 24 3 Overview of the subtidal macrobenthos ........................................................................................... 25 3.1 Are there discrete benthic communities in the Greater Sizewell Bay? ....................................... 26 3.1.1 Infauna............................................................................................................................ 26 3.1.2 Epifauna ......................................................................................................................... 31 3.2 How is the physical environment shaping the distribution of the benthic fauna? ........................ 34 3.2.1 Infauna............................................................................................................................ 35 3.2.2 Epifauna ......................................................................................................................... 38 3.3 What is the natural variability of the benthic invertebrate populations? ...................................... 39 3.3.1 Infauna............................................................................................................................ 40 3.3.2 Epifauna ......................................................................................................................... 47 3.4 What are the dominant biological traits of the benthic macrofauna? .......................................... 55 3.4.1 Infauna............................................................................................................................ 56 3.4.2 Epifauna ......................................................................................................................... 56 3.5 Which are the key benthic taxa in Sizewell Bay? ...................................................................... 61 3.5.1 Selection process ............................................................................................................ 61 3.5.2 Key benthic taxa ............................................................................................................. 61 3.5.3 Molluscs .......................................................................................................................... 63 3.5.4 Crabs and lobsters .......................................................................................................... 70 3.5.5 Shrimps and prawns ....................................................................................................... 72 3.5.6 Polychaetes .................................................................................................................... 77 3.5.7 Echinoderms ................................................................................................................... 82 4 Potential Habitats of conservation interest ...................................................................................... 83 4.1 The Coralline crag .................................................................................................................... 83 4.2 Sizewell-Dunwich Bank (sandbank) .......................................................................................... 86 5 Notes on the future baseline ............................................................................................................. 87 References ............................................................................................................................................... 89 A.1 Technical Reports .................................................................................................................... 94 A.2 Characterisation reports ........................................................................................................... 95 TR348 Sizewell benthic ecology NOT PROTECTIVELY MARKED Page 3 of 122 characterisation A.3 Science Position Papers .......................................................................................................... 95 B.1 Map of the subtidal sampling station ......................................................................................... 96 B.2 Grab surveys (infauna) ............................................................................................................. 97 B.3 2 m-beam Trawl survey (epifauna) ........................................................................................... 98 B.4 Commercial Otter Trawl survey ................................................................................................ 98 B.5 Comprehensive impingement programme (CIMP) .................................................................... 99 C.1 Infauna................................................................................................................................... 100 C.2 Epifauna ................................................................................................................................ 106 C.3 CIMP ..................................................................................................................................... 109 D.1 Environmental parameter ....................................................................................................... 111 D.2 Seabed morphology ............................................................................................................... 113 D.3 Sabellaria spinulosa in the Greater Sizewell Bay .................................................................... 114 D.4 Infaunal Quality Index - reference condition ............................................................................ 116 D.5 Biological trait definitions ........................................................................................................ 117 D.6 Functional traits of the key benthic taxa .................................................................................. 118 D.7 Sabellaria spinulosa reef ........................................................................................................ 121 TR348 Sizewell benthic ecology NOT PROTECTIVELY MARKED Page 4 of 122 characterisation List of Tables and Figures Tables Table 1: Overview of the Key benthic taxa of the Greater Sizewell Bay. ..................................................... 12 Table 2: The BEEMS Sizewell subtidal benthic invertebrate survey series up to 2014. .............................. 18 Table 3: Summary statistics on macro- and meiofauna structural parameters. ........................................... 22 Table 4:Coastal vegetated shingle habitat along the Greater Sizewell Bay coastline. Description, extent (ha) and conservation status obtained from Murdock et al., (2010) and the JNCC website. .............. 24 Table 5: Summary data collected in the Greater Sizewell Bay over the monitoring period 2008-2014 used for the characterisation report. .................................................................................................. 25 Table 6: List of the taxa contributing the most by their abundance to the formation of each of the cluster groups determined by the similarity percentages routine (SIMPER). ........................................