The Manacles Marine Conservation Zone (MCZ) Characterisation Report 2015

MPA Monitoring Programme Contract Reference: MB0129 Report Number: 2 Version 4 August 2018

Project Title: Marine Protected Areas (MPA) Monitoring Programme Report No 2. Title: The Manacles MCZ Characterisation Report 2015 Defra Project Code: MB0129 Defra Contract Manager: Carole Kelly Funded by: Department for Environment, Food and Rural Affairs (Defra) Marine Science and Evidence Unit Marine Directorate Nobel House 17 Smith Square London SW1P 3JR

Authorship

Anna Downie Centre for Environment, Fisheries and Aquaculture Science (Cefas) [email protected]

Jacqueline Eggleton Centre for Environment, Fisheries and Aquaculture Science (Cefas) [email protected]

Paul McIlwaine Centre for Environment, Fisheries and Aquaculture Science (Cefas) [email protected]

Ross Bullimore Centre for Environment, Fisheries and Aquaculture Science (Cefas) [email protected]

Acknowledgements

We thank the Marine Protected Areas Group (MPAG) representatives for reviewing earlier drafts of this report.

Disclaimer: The content of this report does not necessarily reflect the views of Defra, nor is Defra liable for the accuracy of information provided, or responsible for any use of the reports content. Although the data provided in this report have been quality assured, the final products - e.g. habitat maps – may be subject to revision following any further data provision or once they have been used in Statutory Nature Conservation Body (SNCB) advice or assessments.

Cefas Document Control

Title: The Manacles MCZ Characterisation Report 2015

Submitted to: Marine Protected Areas Group (MPAG) Date submitted: February 2018 Portfolio Lead: Clare Leech Project Manager: Mark Etherton Principal Investigator: Sue Ware MPA Programme Science Lead: Joanna Murray, Tammy Noble-James, Ross Bullimore Report compiled by: Anna Downie, Jacqueline Eggleton, Paul McIlwaine Quality control by: Sue Ware, Silke Kröger Approved by & date: Ross Bullimore 08/08/2018 Version: 4

Version Control History Author Date Comment Version Downie et al. 21/12/2016 Draft submitted for MPAG and external review V1 Downie et al. 31/08/2017 Revised draft following MPAG and external review V2 Downie et al. 20/01/2018 Draft submitted following internal QC V3 Downie et al. 08/08/2018 Revised following final MPAG review V4

Contents Contents ...... i Tables ...... iii Figures ...... iv Executive Summary ...... 1 1 Introduction ...... 3 1.1 Site overview ...... 3 1.2 Aims and objectives ...... 7 1.2.1 High-level conservation objectives ...... 7 1.2.2 Definition of favourable condition ...... 7 1.2.3 Report aims and objectives ...... 8 1.2.4 Feature attributes and supporting processes ...... 10 2 Methods ...... 11 2.1 Data sources ...... 11 2.2 Survey design ...... 11 2.3 Data acquisition and processing ...... 13 2.3.1 Acoustic data ...... 13 2.3.2 Seabed imagery ...... 13 2.3.3 Seabed sediments ...... 14 2.4 Data preparation and analysis...... 14 2.4.1 Habitat map ...... 14 2.4.2 Sediment particle size distribution ...... 15 2.4.3 Tidal modelling ...... 15 2.4.4 Physico-chemical properties ...... 16 2.4.5 Biological community data preparation ...... 16 2.4.6 Statistical analyses ...... 17 3 Results and Interpretation ...... 19 3.1 Site overview ...... 19 3.2 Subtidal rock BSH: Physical structure and biological communities ...... 21 3.2.1 A3.1/3.2 High/Moderate energy infralittoral rock ...... 26 3.2.2 A4.1/4.2 High/Moderate energy circalittoral rock ...... 26 3.3 Subtidal sedimentary BSH: Sediment composition and biological communities ...... 30 3.3.1 Subtidal coarse sediment ...... 33 3.3.2 Subtidal sand ...... 34

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3.3.3 Subtidal mixed sediments ...... 37 3.3.4 Subtidal macrophyte-dominated sediment...... 40 3.4 Habitat Features of Conservation Importance (FOCI) ...... 42 3.4.1 Maerl beds ...... 42 3.5 Species Features of Conservation Importance (FOCI) ...... 46 3.5.1 Pink Sea-Fan (Eunicella verrucosa) ...... 46 3.5.2 Other Species FOCI ...... 50 3.6 Non-indigenous species (NIS) ...... 50 3.7 Supporting processes ...... 52 3.7.1 Hydrodynamics: tidal energy and exposure ...... 52 3.7.2 Water quality parameters ...... 52 3.7.3 Sediment quality parameters ...... 53 3.8 Additional monitoring requirements ...... 53 3.8.1 Marine litter ...... 53 4 Discussion ...... 54 4.1 Subtidal rock BSH: Extent, distribution, physical structure and biological communities ...... 54 4.2 Subtidal sedimentary BSH: Extent, distribution, sediment composition and biological communities ...... 55 4.3 Habitat Features of Conservation Importance (FOCI) ...... 56 4.4 Species Features of Conservation Importance (FOCI) ...... 58 4.5 Non-indigenous species (NIS) ...... 58 4.6 Supporting processes ...... 58 4.7 Additional monitoring requirements ...... 58 5 Recommendations for future monitoring ...... 59 6 References ...... 61 Annex 1. Infauna data truncation protocol...... 63 Annex 2. Epifauna data truncation protocol applied to seabed imagery data...... 64 Annex 3. Rationale for using counts of individuals and taxa from still images in condition monitoring...... 68 Annex 4. Marine litter ...... 70 Annex 5. Non-indigenous species (NIS)...... 71

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Tables Table 1. The Manacles MCZ site overview, including General Management Approach (GMA) for designated features...... 6

Table 2. Feature attributes and supporting processes addressed to achieve report objective 1, for The Manacles MCZ...... 10

Table 3. Number of samples collected in each BSH...... 19

Table 4. ANOSIM results for subtidal rock BSH ...... 23

Table 5. The total number of taxa found within and outside of the site boundary for each sedimentary Broadscale Habitat...... 30

Table 6. Top ten taxa contributing to similarity (38.8%) within the ‘A5.4 Subtidal mixed sediments’ group (n=41)...... 37

Table 7. Number of still images with Maerl recorded in each Broadscale Habitat (BSH)...... 42

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Figures Figure 1. Location of The Manacles MCZ in the context of Marine Protected Areas and management jurisdictions proximal to the site...... 5

Figure 2. Location of ground truth samples collected at The Manacles MCZ between 2012 and 2016...... 12

Figure 3. Habitat map of The Manacles MCZ and surrounding area (only subtidal areas included)...... 20

Figure 4. Example images of the rock features acquired at The Manacles MCZ. ... 21

Figure 5. Substrate composition recorded for each video transect segment in 2012, 2015 and 2016...... 22

Figure 6. MNCR habitat classes assigned to each still image acquired for subtidal rock features...... 25

Figure 7. Example images of biotopes observed to be associated with the infralittoral rock feature at The Manacles MCZ...... 27

Figure 8. Example images of biotopes observed to be associated with the circalittoral rock feature at The Manacles MCZ...... 29

Figure 9. Classification of particle size distribution (half phi) information for each sampling point (closed black circles) into one of the sedimentary Broadscale Habitats (coloured areas) plotted on a true scale subdivision of the Folk triangle into the simplified classification for UKSeaMap (Long, 2006; Folk, 1954)...... 31

Figure 10. Distribution of sediment fractions at grab sample locations...... 32

Figure 11. Example images of fauna observed to be associated with the coarse sediment feature at The Manacles MCZ...... 34

Figure 12. Example images of fauna observed to be associated with the subtidal sand feature at The Manacles MCZ...... 36

Figure 13. Example images of fauna observed to be associated with the subtidal mixed sediments feature at The Manacles MCZ...... 39

Figure 14. Example images of the subtidal macrophyte-dominated sediment feature at The Manacles MCZ...... 41

Figure 15. Percentage cover of dead and live Maerl observed in still images...... 43

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Figure 17. Side-scan sonar data acquired around The Manacles MCZ by CIFCA, overlain on multibeam echosounder backscatter data from CCO. Locations of sediment waves identified in the imagery are outlined, indicating whether Maerl has been observed in images...... 46

Figure 18. Mean counts per station of Eunicella verrucosa individuals per still image for each BSH...... 47

Figure 19. Density of Eunicella verrucosa (individuals/m2) in video segments for each BSH...... 47

Figure 20. Number of Eunicella verrucosa individuals observed in each still image...... 48

Figure 21. Abundance of Eunicella verrucosa in video transect segments represented using the SACFOR abundance scale...... 49

Figure 22. Location of grab samples where non-native species were observed. .... 51

Figure 23. Physical environment at The Manacles Marine Conservation Zone. The maps show depth and current conditions (main direction of tidal flow during the flood phase as well as maximum velocity and mean bed shear stress over a spring-neap tidal cycle) in and around the MCZ...... 52

Figure 24. Locations of litter classified by MSFD categories from still imagery, within The Manacles MCZ...... 53

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Executive Summary This report is one of a series of Marine Protected Area (MPA) characterisation and monitoring reports delivered to Defra by the Marine Protected Areas Group (MPAG). The purpose of the report series is to provide the necessary information to allow Defra to fulfil its obligations in relation to MPA assessment and reporting, currently in relation to OSPAR, the UK Marine & Coastal Act (2009) and other relevant Directives (e.g., Marine Strategy Framework Directive). This characterisation report is informed by data acquired during a number of dedicated surveys carried out at The Manacles Marine Conservation Zone (MCZ) (during the period 2012-2016) and will form part of the ongoing time series data and evidence for this MPA.

The Manacles MCZ is an inshore site located on the southern coast of Cornwall within the ‘Western Channel and Celtic Sea’ Charting Progress 2 (CP2) sea area. A number of features of conservation importance (FOCI), including both habitats and species, are designated for protection within The Manacles MCZ. This report provides a description of a number of the Broadscale Habitats (BSHs) ‘A3.1/3.2 High/Moderate energy infralittoral rock’, ‘A4.1/4.2 High/Moderate energy circalittoral rock’, ‘A5.1 Subtidal coarse sediment’, ‘A5.2 Subtidal sand’, A5.4 Subtidal mixed sediments’ and ‘A5.5 Subtidal macrophyte-dominated sediment’), habitat features of conservation importance (FOCI) (‘Maerl Beds’) and species FOCI (Pink Sea_Fan Eunicella verrucosa) designated within the MCZ.

The subtidal habitats within The Manacles MCZ consist of rock habitats surrounded by a mosaic of coarse and mixed sediments, interspersed with small localised patches of sand. The main biotopes observed in association with the infralittoral rock include ‘kelp and red seaweeds (moderate energy infralittoral rock)’ (IR.MIR.KR) and ‘foliose red seaweeds with dense Dictyota dichotoma and/or Dictyopteris membranacea on exposed lower infralittoral rock’ (IR.HIR.KFar.FoR.Dic). The main biotopes observed in association with the circalittoral rock’ include ‘echinoderms and crustose communities’ (CR.MCR.EcCr) and ‘Eunicella verrucosa and Pentapora foliacea on wave exposed circalittoral rock’ (CR.HCR.XFa.ByErSp.Eun).

The majority of the sedimentary habitats surrounding the rock features within the MCZ comprise a mosaic of ‘A5.1 Subtidal coarse sediment’ and ‘A5.4 Subtidal mixed sediments’, which include localised patches of ‘A5.5 Subtidal macrophyte-dominated sediment’. Within The Manacles MCZ these BSHs were mainly characterised by the biotopes ‘red seaweeds and kelps on tide-swept mobile infralittoral cobbles and pebbles’ (SS.SMp.KSwSS.LsacR.CbPb) and ‘Maerl beds’ (SS.SMp.Mrl). The relatively restricted distribution and spatial extent of live Maerl beds identified within the MCZ supports the consideration of a management approach that would facilitate their potential recovery.

The species FOCI Pink Sea-Fan (Eunicella verrucosa) was present primarily in association with the ‘A4.1/4.2 High/Moderate energy circalittoral rock’ features located within and adjacent to the MCZ. Observations were also made of the

The Manacles MCZ Characterisation Report 2015 1 species FOCI Sea-Fan Anemone (Amphianthus dohrnii) in two still images acquired within the MCZ.

Three Non-Indigenous Species (NIS) were also present in the infaunal samples collected within The Manacles MCZ and these included the polychaete worm Goniadella gracilis, the barnacle Hesperibalanus fallax and the gastropod mollusc Crepidula fornicata.

A number of supporting processes were considered as part of this report. Results of tidal modelling indicated that the MCZ faces away from the prevailing westerly winds and mainly has moderate (0.5-1.5 m s-1) to weak (<0.5 m s-1) tidal currents flowing on a southwest-northeast axis. Water and sediment quality assessments were not included as part of the surveys carried out at The Manacles MCZ. However, ten incidences of marine litter were observed in the seabed imagery data and these included fragments of rope and plastic sheet.

A number of recommendations for future assessment and monitoring of designated features within The Manacles MCZ (and other comparable sites) are provided.

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1 Introduction The Manacles Marine Conservation Zone (MCZ) is part of a network of sites designed to meet conservation objectives under the Marine and Coastal Access Act (2009). These sites will also contribute to an ecologically coherent network of Marine Protected Areas (MPAs) across the North-east Atlantic agreed under the Oslo Paris (OSPAR) Convention and other international commitments to which the UK is signatory.

Under the UK Marine & Coastal Access Act (2009), Defra is required to provide a report to Parliament every six years that includes an assessment of the degree to which the conservation objectives set for MCZs are being achieved. In order to fulfil its obligations, Defra has directed the Statutory Nature Conservation Bodies (SNCBs) to carry out a programme of MPA monitoring. The SNCB responsible for nature conservation inshore (between 0 nm and 12 nm from the coast) is Natural England (NE) and the SNCB responsible for nature conservation offshore (between 12 nm and 200 nm from the coast) is the Joint Nature Conservation Committee (JNCC). Where possible, this monitoring will also inform assessment of the status of the wider UK marine environment; for example, assessment of whether Good Environmental Status (GES) has been achieved, as required under Article 11 of the Marine Strategy Framework Directive (MSFD).

This characterisation report primarily explores data acquired from the first dedicated monitoring survey of The Manacles MCZ, which will form the initial point in a monitoring time series against which feature (and site) condition can be assessed in the future. The specific aims of the report are discussed in more detail in section 1.2. 1.1 Site overview The Manacles MCZ is an inshore site on the southern coast of Cornwall (Figure 1). The Manacles MCZ was recommended as an MCZ by the ‘Finding Sanctuary’ regional stakeholder group project. It is located in the jurisdictional area of the Cornwall Inshore Fisheries Conservation Authority (IFCA) and falls within the wider ‘Charting Progress 2’ (CP2) area ‘Western Channel and Celtic Sea’. The site is neighboured by Mounts Bay and Runnel Stone (Land’s End) designated MCZs as well as the Fal and Helford Special Area of Conservation (SAC), the Land’s End and Cape Bank SAC and the Lizard Point SAC (Figure 1).

The MCZ extends 2 km from the shoreline, ranging from the intertidal to a water depth of ~60 metres below sea level (chart datum). The site encompasses a series of large underwater rocky outcrops known as The Manacles, which are located within a mosaic of large boulders and muddy shell gravel, with sand deposits in the more sheltered bays along the coast.

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The site was designated due to the presence of high quality reef features and a number of associated species of conservation interest1. The rocky reef habitat, which is covered in a hydroid/bryozoan turf, supports dense populations of Pink Sea- Fans (Eunicella verrucosa), small Sea-Fan Anemones (Amphianthus dohrnii) and the Stalked Jellyfish (Haliclystus auricula), as well as the commercially important European Lobster (Homarus gammarus) and the Spiny Lobster (Palinurus elephas).

The sedimentary habitats that surround the area support Maerl beds, which create structures for urchins, anemones and sea cucumbers to burrow in to (Lieberknecht et al., 2011). The spatial extent of The Manacles MCZ is less than the minimum required, as described in the Ecological Network Guidance (ENG) (Natural England, 2010), for the protection of Broadscale Habitats (i.e., minimum diameter of 5 km with mean size 10-20 km in diameter). Therefore, the presence of sedimentary Broadscale Habitats (BSH) was not a primary reason for the recommendations for designation of this site (Lieberknecht et al., 2011). However, The Manacles MCZ Designation Order 2013, and a subsequent Manacles MCZ Designation (Amendment) Order 2016, lists three sedimentary subtidal BSHs as protected features: ‘A5.1 Subtidal coarse sediment’, ‘A5.2 Subtidal sand’ and ‘A5.4 Subtidal mixed sediments’. Table 1 lists the BSHs and Features of Conservation Importance (FOCI) that have been reported at the site in the Site Assessment Document (SAD) (Lieberknecht et al., 2011) and the Site Report (Brown and Mitchell, 2016) based on a dedicated site verification survey. The features afforded protection in the site designation order and the General Management Approach (GMA) to be applied to each feature are also provided in Table 1.

1 http://www.legislation.gov.uk/ukmo/2013/13/pdfs/ukmo_20130013_en.pdf [accessed 06/02/2018]

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Figure 1. Location of The Manacles MCZ in the context of Marine Protected Areas and management jurisdictions proximal to the site.

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Table 1. The Manacles MCZ site overview, including General Management Approach (GMA) for designated features.

Site Details Charting Progress 2 Region2 Western Channel & Celtic Sea Spatial Area (km2) 3.5 Water Depth Range (m) 0-60 Existing Data & Information Brown, L., and Mitchell, P. (2016). The Manacles MCZ Post-Survey Site Report. 90 pp. Godsell. N. et al. (2013). The Manacles rMCZ Survey Report. 60 pp. Arnold, K. (2016). The Manacles MCZ 2015 Survey Report. 136 pp. Naylor, H. et al. (2016). Manacles MCZ Drop Down Video (20160516_CIFCA_MCZ_MAN_DDV) Survey Field Report. 20 pp. Trundle, C. et al. (2016). Manacles MCZ Sidescan (20160303_MCZ_MAN_SSS) Survey Field Report. 17 pp.

Current & Proposed Management Measures CIFCA Byelaw-Prohibition of bottom towed gear with The Manacles MCZ3 Features Present (BSH) Designated GMA A1.2 Moderate energy intertidal rock* ✓ Maintain A2.1 Intertidal coarse sediment* ✓ Maintain A2.2 Intertidal sand and muddy sand*  N/A A2.3 Intertidal mud*  N/A A2.4 Intertidal mixed sediments*  N/A A3.1 High energy infralittoral rock  N/A A3.2 Moderate energy infralittoral rock ✓ Maintain A4.2 Moderate energy circalittoral rock ✓ Maintain A5.1 Subtidal coarse sediment ✓ Recover A5.2 Subtidal sand ✓ Maintain A5.4 Subtidal mixed sediments ✓ Recover A5.5 Subtidal macrophyte dominated sediment ✓ Recover Features Present (Habitat FOCI) Maerl Beds ✓ Recover Features Present (Species FOCI) Sea-Fan Anemone (Amphianthus dohrnii)** ✓ Maintain Spiny Lobster (Palinurus elephas)** ✓ Recover Pink Sea-Fan (Eunicella verrucosa)** ✓ Recover Stalked Jellyfish (Haliclystus auricular)** ✓ Maintain Sunset Cup Coral (Leptosammia pruvoti)**  N/A * The characterisation survey reported here did not extend into the intertidal. **The characterisation survey was not specifically designed to target species FOCI.

2http://webarchive.nationalarchives.gov.uk/20141203170558tf_/http://chartingprogress.defra.gov.uk/ [accessed 06/02/2018] 3https://secure.toolkitfiles.co.uk/clients/17099/sitedata/Byelaws%20and%20orders/Cornwall_IFCA/Ma nacles-MCZ-byelaw.pdf [accessed 06/02/2018]

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1.2 Aims and objectives

1.2.1 High-level conservation objectives High-level site-specific conservation objectives serve as benchmarks against which the efficacy of the GMA in achieving the conservation objectives (i.e., maintaining designated features at, or recovering them to, ‘favourable condition’) can be assessed and monitored.

As detailed in The Manacles MCZ designation order1, the conservation objectives for the site are that the designated features:

a) So far as already in favourable condition, remain in such condition; and

b) So far as not already in favourable condition, be brought into such condition, and remain in such condition.

It should be noted that the ‘maintain’ GMAs have been applied based on a proxy assessment, as opposed to being based on empirical monitoring evidence (i.e., direct observations). As such, the vulnerability assessment took into account the level of exposure of the features to those pressures to which they are perceived to be sensitive.

1.2.2 Definition of favourable condition For habitat features, a number of attributes4 are assessed and monitored to determine whether or not features are in favourable condition.

Favourable condition, with respect to a habitat feature, means that:

a) Its extent and distribution is stable or increasing;

b) Its structures and functions, including its quality, and the composition of its characteristic biological communities, are such as to ensure that it remains in a condition which is healthy and not deteriorating; and

c) Its natural supporting processes are unimpeded.

The extent of a habitat feature refers to the total area in the site occupied by the qualifying feature and must also include consideration of its distribution. A reduction in feature extent has the potential to alter the physical and biological functioning of sedimentary habitat types (Elliott et al., 1998). The distribution of a habitat feature influences the component communities present and can contribute to the condition and resilience of the feature (JNCC, 2004).

The assessment and monitoring of extent is only appropriate for those features with a discrete boundary, which are likely to be affected by pressures that can be regulated as part of the management approach. Examples of such features are,

4https://designatedsites.naturalengland.org.uk/Marine/SupAdvice.aspx?SiteCode=UKMCZ0018&Site Name=manacles&SiteNameDisplay=The+Manacles+MCZ&countyCode=&responsiblePerson=&SeaA rea=&IFCAArea= [accessed 06/02/2018]

The Manacles MCZ Characterisation Report 2015 7 among others, biogenic reefs and Maerl beds. The spatial extent of most Broadscale Habitats is not likely to change in response to most pressures. Exceptions to this include activities such as dredging and disposal of dredged materials, which will directly impact the type of seabed habitat present. The other components (i.e., feature structure and function) are more appropriate measures of favourable condition for most habitat features. Feature and sub-feature specific targets (and details of their supporting processes) are provided in the supplementary advice4 for designated sites.

Structure encompasses the physical components of a habitat type and the key and influential species present. Physical structure refers to topography, sediment composition and distribution. Physical structure can have a significant influence on the hydrodynamic regime operating a varying spatial scales in the marine environment, as well as influencing the presence and distribution of associated biological communities (Elliott et al., 1998). The function of habitat features includes processes such as: sediment reworking (e.g., through bioturbation) and habitat modification, primary and secondary production and recruitment dynamics. Habitat features rely on a range of supporting processes (e.g., hydrodynamic regime, water quality and sediment quality), which act to support their functioning as well as their resilience (e.g., ability to recover following impact).

For species features, favourable condition means that:

a) The quality and quantity of its habitat are such as to ensure that the population is maintained in numbers which enable it to thrive;

b) The composition of its population in terms of number, age and sex ratio are such as to ensure that the population is maintained in numbers which enable it to thrive; and

c) Its natural supporting processes are unimpeded.

1.2.3 Report aims and objectives The primary aim of this report is to explore and describe the attributes of the designated features within The Manacles MCZ, to enable future assessment and monitoring of feature condition. The results presented will be used to develop recommendations for future monitoring, including the operational testing of specific metrics which may indicate whether the condition of the feature has been maintained, is improving or is in decline.

The specific objectives of this monitoring report are provided below:

1. Provide a description of the extent5, distribution, structural and (where possible) functional attributes, and the supporting processes, of the designated features within and adjacent to the site (see Table 2 for

5 Note that where current habitat maps are not available, extent will be described within the limits of the available data.

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more detail), to enable subsequent condition monitoring and assessment;

2. Note observations of any Habitat or Species FOCI not covered by the Designation Order as features of the site;

3. Present evidence relating to marine litter (Descriptor 10), to satisfy requirements of the Marine Strategy Framework Directive;

4. Present evidence relating to non-indigenous species (Descriptor 2), to satisfy requirements of the Marine Strategy Framework Directive;

5. Provide practical recommendations for appropriate future monitoring approaches for both the designated features and their natural supporting processes (e.g., metric selection, survey design, data collection approaches) with a discussion of their requirements.

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1.2.4 Feature attributes and supporting processes To achieve report objective 1, the report will present evidence on a number of feature attributes and supporting processes, as defined in the supplementary advice on conservation objectives developed by Natural England for the designated features within The Manacles MCZ6. It should be noted that it was not possible to address all feature attributes in the monitoring characterisation survey, given the comprehensive nature of the attribute list for each feature. The feature attributes were therefore rationalised and prioritised, resulting in a smaller sub-set.

The list of selected feature attributes and supporting processes considered in this report is presented in Table 2, alongside the generated outputs for each.

Table 2. Feature attributes and supporting processes addressed to achieve report objective 1, for The Manacles MCZ.

Feature attributes Features Outputs Extent and distribution A3.2 Moderate energy infralittoral rock Habitat map A4.2 Moderate energy circalittoral rock A5.1 Subtidal coarse sediment A5.2 Subtidal sand A5.4 Subtidal mixed sediments A5.5 Subtidal macrophyte dominated sediment

Physical structure of rocky A3.2 Moderate energy infralittoral rock Habitat map substrate A4.2 Moderate energy circalittoral rock Sediment composition and A5.1 Subtidal coarse sediment Habitat map and PSA distribution A5.2 Subtidal sand derived from seabed A5.4 Subtidal mixed sediments sediment samples Presence and spatial distribution A3.2 Moderate energy infralittoral rock Biological communities of biological communities A4.2 Moderate energy circalittoral rock (and biotopes) derived A5.1 Subtidal coarse sediment from ground truth Presence and abundance of key A5.2 Subtidal sand samples structural and influential species A5.4 Subtidal mixed sediments A5.5 Subtidal macrophyte dominated sediment Species composition of component communities Non-indigenous species (NIS) The Manacles MCZ Location of samples where NIS were recorded Presence and distribution of the Pink Sea-Fan (Eunicella verrucosa) Presence and species abundance of individuals observed in seabed imagery data Extent of supporting habitats Pink Sea-Fan (Eunicella verrucosa) Habitat map Energy/exposure The Manacles MCZ Tidal model

6https://designatedsites.naturalengland.org.uk/Marine/MarineSiteDetail.aspx?SiteCode=UKMCZ0018 &SiteName=fal&countyCode=&responsiblePerson=&SeaArea=&IFCAArea= [accessed 06/02/2018]

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2 Methods

2.1 Data sources

Data used to inform this characterisation report have been compiled from surveys carried out at The Manacles MCZ between 2012 and 2016 by the Environment Agency (EA) (Godsell et al., 2013; Arnold, 2016) and the Cornwall Inshore Fisheries and Conservation Authority (CIFCA) (Naylor et al., 2016; Trundle et al., 2016). Locations of video tows and grab samples collected during these surveys are shown in Figure 2.

2.2 Survey design

Forty-two stations located within the MCZ boundary were planned for survey in September 2012 by the EA to support the verification of feature presence and distribution. The station positions were selected using a triangular lattice spaced 200 m apart. Of the 42 planned stations, 35 were successfully sampled using the drop-down camera system with viable grab samples also acquired at 17 of the planned stations. These sampling stations were revisited and expanded upon during a second survey in 2015, to support a more detailed characterisation of the features designated within the MCZ along with comparable features present within the wider environment adjacent to the site. As such, in order to collect additional habitat data beyond the MCZ boundary, the grid was extended to include an additional 42 stations to the north and south of the MCZ boundary, within the 50 m depth contour (Figure 1).

For vessel safety reasons, 200 m buffer zones around The Manacles rocks were incorporated into the survey plan (Arnold, 2016). Eleven additional transects of still images (no video acquired) were previously acquired in July 2014 by the CIFCA to specifically target the Maerl features within the MCZ, identified during an earlier scoping study (Naylor et al., 2016). Still images and video from an additional eight transects, comprising five stations (two stations were split into multiple tows) were collected in May 2016 in the previously un-surveyed area close to The Manacles rocks.

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Figure 2. Location of ground truth samples collected at The Manacles MCZ between 2012 and 2016.

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2.3 Data acquisition and processing 2.3.1 Acoustic data Multibeam echosounder (MBES) bathymetry and backscatter data for the MCZ and surrounding area exists as three distinct layers. Block 1 and Block 2 acoustic data were commissioned by the Maritime Coastguard Agency (MCA) and collected by Netsurvey in 2013 aboard MV Ping using a Simrad Kongsberg EM3002D multibeam Echosounder. The layers were downloaded from the UK Hydrographic Office (UKHO) INSPIRE Portal website. Nearshore acoustic data (Block 3) were collected on behalf of the Channel Coastal Observatory (CCO) in 2013 aboard MV Wessex Explorer using a Simrad Kongsberg EM3002D multibeam echosounder. Block 3 was downloaded from the CCO website. Bathymetry data for Block 1 were gridded at 5 m resolution, and Blocks 2 and 3 data were gridded at 2 m resolution. The backscatter layers were gridded at 1 m. However, the area of backscatter data, which coincided with the bathymetry data at 5 m resolution, was gridded up to 5 m resolution for analysis. Full details on the acquisition and processing of acoustic data can be found in the Manacles site verification report (Brown and Mitchell, 2016).

The Cornwall Inshore Fisheries Conservation Authority (CIFCA) shared Edgetech 4200 dual frequency sidescan was used to carry out an acoustic survey of the central part of The Manacles MCZ during the 2016 CIFCA survey (Trundle et al., 2016). Due to the size and the complex bathymetry of the site, the sidescan unit was towed continuously for the duration of the survey at a constant depth. Data were acquired at both the 300 and 600 kHz frequencies using Edgetech’s Discover software and data were recorded in .jsf and .xtf file formats. Position of the towed sidescan system was estimated by recording the deployment point height above the water, the length of cable out and the distance aft of the vessel where the cable entered the water. Positions (in WGS84) and times (UTC), were both recorded using a Furuno GP 32 GPS receiver.

2.3.2 Seabed imagery Seabed imagery data were collected using a drop-down video system which consisted of a digital stills and video camera mounted on a frame. The seabed imagery data were intended to contribute to the characterisation of epifaunal communities associated with both the rock and sedimentary habitat features. All data were collected following MESH Recommended Operating Guidelines (ROG) (Coggan et al., 2007). In the 2012 and 2015 EA surveys, video and still images were collected using a Seaspyder drop camera system. Real time navigation data acquisition and manual position fixing was captured via Trimble® HYDROpro™ software. Full details can be found in the survey reports (Godsell et al., 2013; Arnold, 2016). Images of the seabed were acquired every 10-15 m over a distance of ~150 m. Additional images were collected in heterogeneous areas of BSH and if particular habitats or species FOCI were observed, to ensure, as far as possible, that the habitats and species were adequately sampled and accurately identified.

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The CIFCA surveys used a drop camera system with a Kongsberg OE14-208 stills camera in 2014 and a Seaspyder Subsea camera system in 2016. Start and end positions of transects were recorded using Olex track recording and a still image was taken at the start of the tow with the positions of individual stills images recorded separately. Video was collected continuously with still images captured at 60 second intervals. During both surveys, the camera was landed onto the seabed for every still to ensure the highest quality images were obtained (Naylor et al., 2016).

2.3.3 Seabed sediments Seabed sediment samples for particle size distribution and benthic infauna analyses were collected using a 0.1 m2 Hamon Grab (also known as a ‘mini’ Hamon Grab).

A 500 ml sub-sample was taken from each grab sample and stored at -20°C prior to determining the particle size distribution. Sediment samples were processed by National Laboratory Service following the recommended methodology of the North East Atlantic Marine Biological Analytical Quality Control (NMBAQC) scheme (Mason, 2011). The less than 1 mm sediment fraction was analysed using laser diffraction and the greater than1 mm fraction was dried, sieved and weighed at 0.5 phi (ϕ) intervals. Sediment distribution data were merged and used to classify samples into sedimentary Broadscale Habitats.

The faunal fraction was sieved over a 1 mm mesh, photographed then fixed in buffered 4% formaldehyde. Faunal samples were processed by APEM Ltd to extract all fauna present in each sample. Fauna were identified to the lowest taxonomic level possible, enumerated and weighed (blotted wet weight) to the nearest 0.0001 g following the recommendations of the NMBAQC scheme (Worsfold et al., 2010).

2.4 Data preparation and analysis 2.4.1 Habitat map A habitat map showing the distribution of BSH in and around The Manacles MCZ was produced for the Site Verification Report. Full details on the acquisition and processing of acoustic data and a detailed description of mapping methodology can be found in this report: Brown and Mitchell, 2016.

The habitat map is based on object-based image analysis (OBIA) and statistical modelling of acoustic and ground truth data. This process was undertaken separately for three Blocks of acoustic data. Bathymetry data for Block 1 were gridded at 5 m resolution, and Blocks 2 and 3 data were gridded at 2 m resolution. The backscatter layers were gridded at 1 m. However, the area of backscatter data which coincided with the bathymetry data at 5 m resolution was gridded up to 5 m resolution for analysis.

Segmentation of the acoustic blocks was carried out in eCognition (vs9.1) using the multiresolution segmentation algorithm on varying combinations of GIS layers consisting of bathymetry, backscatter, BPI, slope and rugosity. In each case, the segmentation was undertaken at the pixel level with a scale parameter of 5.

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Conditional Inference (CI) analysis (Hothorn et al., 2006) run in R (R Core Team, 2015) was used to identify the acoustic and derivative variables that most successfully differentiated between the BSH observed in the ground truth datasets, and to establish the best cut-off values for those variables. The analysis was completed in two stages, first separating areas of rock from areas of sediment and, in a second step, further classifying inside those categories.

The habitat map was further extended to cover inshore sections outside the MCZ that were not covered by the verification map. The sections were not mapped as part of the original habitat map because backscatter data were not available for those sections. In the added sections, rock and sediment were separated based on bathymetric rugosity (VRM10 > 0.0005).

All sediments were initially classified as ‘A5.1/5.4 Subtidal coarse/mixed sediments’. In the absence of backscatter data, it is not possible to rule out the presence of patches of sand. To the south of the site, the presence of sand is unlikely on the basis that observed sand occurred in current velocities that are weaker than indicated in that area. In the north of the site, however, a boundary conflict with the verification map was observed, where sand was identified from the backscatter data. Through comparison of the bathymetry and backscatter data available, it was possible to manually extend the patches of sand into the area outside the backscatter data following bathymetric relief, to give a more accurate border between the two sediment types.

Rock was split into infralittoral and circalittoral categories according to a depth boundary (21 m) identified using the ground truth data. All of the instances of ‘infralittoral rock’ and ‘circalittoral rock’ have been incorporated into composite habitats ‘A3.1/3.2 High/Moderate energy infralittoral rock’ and ‘A4.1/4.2 High/Moderate energy circalittoral rock’. Although still images from the ground truth data were initially classified to high or moderate energy levels investigation of the communities present and the available modelling of prevailing energy conditions conclude that at this site it is not feasible to resolve the fine scale changes in energy regime in this site (see Section 3.2 for detail of the rationale applied).

2.4.2 Sediment particle size distribution Sediment particle size distribution data (half phi classes) were grouped into the percentage contribution of gravel, sand and mud derived from the classification proposed by Folk (1954). In addition, each sample was assigned to one of four sedimentary Broadscale Habitats using a modified version of the classification model produced during the Mapping European Seabed Habitats (MESH) project (Long, 2006).

2.4.3 Tidal modelling Mean and maximum tidal current velocities (m s-1) at the seabed and mean and maximum bed shear stress were obtained from a hydrodynamic model built for the study area. The depth-averaged model of The Manacles MCZ is nested with a

The Manacles MCZ Characterisation Report 2015 15 larger English Channel model and has been built using an unstructured triangular mesh, using the hydrodynamic software Telemac2D (v7p1). The model domain extends 48.01°N – 52.48°N and 2.23°E – 9.51°W. The unstructured mesh was discretised with 292,630 nodes and 571,260 elements. The mesh has a resolution of approximately 3 km along the open boundary. In the area of interest, the resolution is refined to approximately 25 m. Bathymetry for the model was sourced from the Defra Digital Elevation Model (Astrium, 2011). The resolution of the dataset is 1 arc second (~30 m). In the area of the MCZ, the MBES bathymetry from the area was used, gridded to a 2 m resolution. The hydrodynamics are forced along the open boundaries using 11 tidal constituents (M2, S2, N2, K2, K1, O1, P1, Q1, M4, MS4 and MN4) from the OSU TPXO European Shelf 1/30° regional model [2]. After a spin up period of 5 days, the model was run for 30 days to cover a full spring- neap cycle. Bed shear stress (N/m2) was calculated according to Soulsby (1997), based on current speed and local sediment characteristics (derived from the habitat map and sediment samples). It should be noted that this model does not include wave or wind energy, and therefore does not provide a complete indication of hydrodynamics. In particular it is acknowledged that wave action at shallower depths will be altering the energy conditions experienced by the communities present and therefore this modelling will not resolve these small scale changes in energy regime.

2.4.4 Physico-chemical properties No water or sediment quality parameters were acquired as part of the surveys at The Manacles MCZ included in this report. Observations of marine litter on the seabed were recorded (using the protocol provided in Annex 5) as part of the analyses of video and still image data.

2.4.5 Biological community data preparation Benthic macrofauna data sets were checked to ensure consistent nomenclature and identification policies. Any discrepancies identified were resolved using expert judgement following the truncation steps presented in Annex 2. Invalid taxa and fragments of countable taxa were removed from the data set, while the presence of colonial taxa was changed to a numerical value of one. Records were combined where a species was identified correctly both by using its binomial name and by using its binomial name with a qualifier e.g. Lumbrinereis cingulata ‘aggregate’. Records labelled as ‘juvenile’ were combined with adults of the same genus/species/family.

Three of the four still image data sets (2012, 2014 and 2015) included abundance records for taxa identified in the images. A considerable difference was evident in the taxonomic detail between the analysis of stills acquired in 2012 and 2014-2015. Consequently, two community data sets were created with different levels of truncation following the steps provided in Annex 3. In both datasets, fish and uncertain identification at the level of Animalia were removed. All taxa observed were combined to the lowest common taxonomic level. As the 2012 dataset was

The Manacles MCZ Characterisation Report 2015 16 less taxonomically resolute, a combined dataset was produced where by sponges, bryozoans as well as red and brown algae (other than Laminarians, which are very conspicuous and have been identified in both datasets) were simplified to a morphological category. The data preparation and truncation resulted in 55 taxa included in the 2012-2015 dataset and 95 taxa in the 2014-2015 dataset.

Different modes of recording abundance (percent cover vs. individual counts) prevented the aggregation of observed abundances across the taxa combined in the truncation step. In order to retain some information relating to abundance for the subsequent community analyses, SACFOR scores were converted to a numerical ordinal scale from 1 (rare) to 6 (superabundant). No additional transformations were applied to these data ahead of the multivariate analyses, as the 1-6 numerical transformation of the SACFOR score is already considered to be a log-transformed and scaled dataset. Furthermore, as ordinal scores cannot be added or averaged, the maximum score of the combined taxa was adopted for each truncated entry.

The infaunal and epifaunal species abundance data (generated from the infaunal samples and seabed imagery data respectively) were cross-referenced against a list of 49 non-indigenous target species which have been selected for assessment of Good Environmental Status in GB waters under MSFD Descriptor 2 (Stebbing et al., 2014; Annex 5). The list includes two categories; species which are already known to be present within the assessment area (present) and species which are not yet thought to be present but have a perceived risk of introduction and impact (horizon). An additional list of taxa, which were identified as invasive in the ‘Non-native marine species in British waters: a review and directory’ (Eno et al., in 1997) was also used to cross reference against all taxa observed (Annex 5).

2.4.6 Statistical analyses The truncated macrofauna abundance and biomass data were imported into PRIMER v6 (Clarke and Gorley, 2006) to enable multivariate analysis and the derivation of various metrics for univariate analysis. Species classification information and a number of relevant factors/indicators were also assigned to the data at this stage. The number of taxa (S), Margalef’s species richness (d), total abundance of enumerable individuals (N) and Shannon (Loge) and Hills (N1) diversity metrics were derived for each sample using the DIVERSE function within PRIMER v6. These metrics can be considered as a standard suite of ecologically meaningful measures of diversity and were selected to assess differences between 1) designated habitat features and 2) biological community characteristics of comparable features located inside and outside of the MCZ boundary. Non-metric multidimensional scaling (MDS) ordination plots, analysis of similarity between (ANOSIM) and within (SIMPER) groups were produced in PRIMER v6 to explore potential differences in biological community composition between the habitat features and also between examples of comparable features located within and out with the site boundary.

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Summary statistics, data interpretation/manipulation and non-parametric Wilcoxon tests were performed on the sample level metrics to test for and explain any significant differences between groups (R core team, 2015). This non-parametric test does not require the data to be normally distributed and yields equivalent results to the parametric t-test on normally distributed data. A probability value (p) of 0.05 or less was considered to be statistically significant.

The same analyses were conducted on the epifauna ordinal abundance data, with the distinction of number of taxa (S) being the only generated diversity metric, and the inclusion of all Broadscale Habitat types.

Abundance of the species FOCI Eunicella verrucosa was recorded as the number of individuals observed in each still for all four datasets (e.g., collected in 2012, 2014, 2015 and 2016). In the absence of consistent image area and number of images, the abundance per station in still images was represented by the mean count per image for each tow. The averaging approach assumes a similar variability in image area for each tow and is explained in detail in Annex 3. Each still was allocated to a Broadscale Habitat type and location (i.e., inside or outside of the MCZ boundary). Some transects crossed the MCZ boundary. In these cases, stills within 5 m of the boundary were classified as being inside the site. For each station (transect) abundance was averaged across stills in each BSH type (to account for the effect of habitat association of the species). The mean abundance at each station formed the sample unit for comparison of abundance in BSH strata located inside and outside the MCZ (see Annex 4 for further details).

Eunicella verrucosa abundance was recorded from video transects for three of the four datasets. Individual counts per video segment (change in habitat type begins a new segment) were recorded using the 2015 and 2016 datasets. In the 2012 video dataset, abundance values were only available as a SACFOR score. Individual counts were converted to densities (individuals m-2) by estimating the area covered by each transect as ‘segment length (m) x 0.6 m’. Densities in the 2015 and 2016 data sets were converted to SACFOR according to MNCR (1990) for consistent illustrative purposes. Segments were assigned a location inside and outside the MCZ based on the centroid of the transect. Comparisons of mean abundance in each BSH located inside and outside of the MCZ were calculated using the density values derived from the 2015 and 2016 data.

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3 Results and Interpretation

3.1 Site overview

The Manacles MCZ subtidal habitats consist of rock habitats surrounded by a mosaic of coarse and mixed sediments interspersed by small pockets of sand (Figure 3). It was not possible to delineate the coarse and mixed sediments in the habitat map due to their acoustically indistinct properties. Variability was also observed in sediment classifications at a given station between sampling occasions (for both seabed imagery and sediment particle size distributions), with stations visited twice alternating between coarse or mixed sediments classifications. However, because surveys in 2012 and 2015 were conducted at different times of year (March vs. September), it is not possible to establish whether the differences are due to seasonal variability in siltation, or longer temporal changes in the composition and distribution of the seabed sediments. Also, although samples have been collected nominally at the same station, there is often up to 60 m variation in spatial location of the seabed sampled. Consequently, fine-scale spatial variability may also be the cause of the observed differences in sediment type at a given station between sampling occasions.

Habitats observed inside and outside the MCZ cover a similar range of substrata, water depths and prevailing energy conditions (Figure 3). However, as a habitat map was not available at the time of designing the surveys, grab sampling is very biased towards the mixed sediments (Table 3). Sand only occurs in localised patches and, because of this, is not comprehensively sampled. No records of Maerl or macrophyte-dominated sediment exist from outside of the MCZ. The imbalance in sample numbers across BSH means that the univariate metrics derived to assess feature condition cannot be compared across all designated habitats and any comparisons between time intervals will not be statistically robust. As such, it is recommended that additional stations need to be identified and sampled to achieve a more comprehensive and robust experimental design for the next phase of monitoring.

Table 3. Number of samples collected in each BSH.

Broadscale Habitat (BSH) Grab – PSA Grab – PSA Video Stills & Infauna only In Out In Out In Out In Out A3.1 High energy infralittoral rock N/A N/A N/A N/A 6 5 3 16 A3.2 Moderate energy infralittoral N/A N/A N/A N/A 11 2 87 19 rock A4.1 High energy circalittoral rock N/A N/A N/A N/A 20 13 70 56 A4.2 Moderate energy circalittoral N/A N/A N/A N/A 4 0 42 1 rock A5.1 Subtidal coarse sediment 7 5 - - 29 8 304 75 A5.2 Subtidal sand 3 3 - - 13 4 129 39 A5.4 Subtidal mixed sediments 18 23 - - 31 33 404 198 A5.5 Macrophyte-dominated - - - - 5 0 87 0 subtidal sediment

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Figure 3. Habitat map of The Manacles MCZ and surrounding area (only subtidal areas included).

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3.2 Subtidal rock BSH: Physical structure and biological communities

The rock feature at the site comprises bedrock overlain by boulders and cobbles (Figure 4 and Figure 5). The main biotopes initially identified upon review of still images include ‘Kelp and red seaweeds (moderate energy infralittoral rock)’ (IR.MIR.KR) and ‘Foliose red seaweeds with dense Dictyota dichotoma and/or Dictyopteris membranacea on exposed lower infralittoral rock’ (IR.HIR.KFaR.FoR.Dic) in the infralittoral, and ‘Echinoderms and crustose communities’ (CR.MCR.EcCr) and ‘Eunicella verrucosa and Pentapora foliacea on wave-exposed circalittoral rock’ (CR.HCR.XFa.ByErSp.Eun) in the circalittoral (Figure 4 and Figure 6).

High energy infralittoral rock Moderate energy infralittoral rock

High energy circalittoral rock Moderate energy circalittoral rock

Figure 4. Example images of the rock features acquired at The Manacles MCZ.

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Figure 5. Substrate composition recorded for each video transect segment in 2012, 2015 and 2016.

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Initial investigation of the community data and classification of individual still images indicated that both high and moderate energy infralittoral and circalittoral rock Broadscale Habitats were present at the site. Statistical analysis of the biological data however does not support any delineation between energy categories within these data.

Biological community characteristics observed in the still images assigned to ‘A3.1 High energy infralittoral rock’ and ‘A3.2 Moderate energy infralittoral rock’ do not significantly differ from each other and similarly, ANOSIM analyses of the biological community composition in still images indicate very little or no significant difference between ‘A4.1 High energy circalittoral rock’ and ‘A4.2 Moderate energy circalittoral rock’ (Table 4.).

Table 4. ANOSIM results for subtidal rock BSH

ANOSIM results

Large dataset pairwise Small dataset pairwise

‘A3.1 High energy infralittoral rock’ and R = 0.028, p = 0.3 R = -0.01, p = 0.57 ‘A3.2 Moderate energy infralittoral rock’

‘A4.1 High energy circalittoral rock’ and R = 0.115, p = 0.007 R = 0, p = 0.49 ‘A4.2 Moderate energy circalittoral rock’

‘A3.1/3.2 High/Moderate energy R = 0.537, p = 0.001 R = 0.571, p = 0.001 infralittoral rock’ and ‘A4.1/4.2 High/Moderate energy circalittoral rock’

The classification of some still images to ‘high energy’ BSH categories has arisen from application of the MNCR and EUNIS habitat classifications’ strict hierarchical structure to each individual still image. The still images that have been assigned to the ‘high energy’ infralittoral biotope (IR.HIR.KFaR.FoR.Dic) tend to lack kelp and have more associated fauna, but otherwise the biological communities observed are largely the same. Classification into the ‘high energy’ circalittoral biotope (CR.HCR.XFa.ByErSp.Eun) results from the presence of Eunicella verrucosa and Pentapora foliacea among fauna that are otherwise similar to the biological communities observed to be associated with the rock feature assigned as ‘moderate energy’. However, whilst the biotopes IR.HIR.KFaR.FoR.Dic and CR.HCR.XFa.ByErSp.Eun are both assigned as ‘high energy’, a more detailed examination of the descriptions given for the two biotopes indicates both also occur at moderate wave exposure and current conditions. This further investigation of the communities present further does not support delineation between energy categories within these data.

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The tidal modelling available for the site suggests that the site is subject to only moderate energy levels. Average current speeds derived from the tidal model (mean current speed over a spring-neap cycle) do not exceed 1.5 m/s and, although fairly open, the site faces away from prevailing westerly winds. This tidal modelling alone however must be treated with caution. This modelling does not include wave action which at shallower depths will be altering the energy conditions experienced by the communities present and therefore is not able to resolve these small scale changes in energy regime. At this site it is not feasible to delineate the infralittoral or circalittoral rock habitats into component features defined by energy regime.

Consequently, all of the instances of ‘infralittoral rock’ and ‘circalittoral rock’ have been incorporated into composite habitats ‘A3.1/3.2 High/Moderate energy infralittoral rock’ and ‘A4.1/4.2 High/Moderate energy circalittoral rock’ for the purposes of further analysis in this report.

ANOSIM analysis of the biological communities associated with these composite habitats ‘A3.1/3.2 High/Moderate energy infralittoral rock’ and ‘A4.1/4.2 High/Moderate energy circalittoral rock’ indicates this represents a statistically valid delineation with a significant difference between these two habitats (Table 4). Both rock habitats support a faunal turf of bryozoans and hydroids, as well as a diverse echinoderm fauna. The foliose red and brown seaweeds and Laminarian kelp species forming the dominant taxa in the infralittoral, are replaced in the circalittoral by a multitude of epifauna, including caryophyllids, Eunicella verrucosa, Alcyonium sp. and various other sponge and anthozoan species, with locally abundant feather stars (Antendonidae).

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Figure 6. MNCR habitat classes assigned to each still image acquired for subtidal rock features.

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3.2.1 A3.1/3.2 High/Moderate energy infralittoral rock The habitat ‘A3.1/3.2 High/Moderate energy infralittoral rock’ is characterised by a mixture of kelp, foliose red and brown algae along with filamentous red algae, encrusting coralline algae, cup corals and faunal turf (Figure 7). The most common taxa observed included Laminaria sp., Dictyopteris polypodioides, Bonnemaisonia sp., Cheilostomatida, Smittinoidea, Polyclinidae and Serpulidae.

An ANOSIM analysis comparing community composition in still images acquired from the infralittoral rock habitat during 2014-2015, inside and outside the MCZ, indicated very little difference (Global R = 0.082, p = 0.002).

Similarly, no significant difference was observed in the number of taxa (S) between the infralittoral rock feature located inside and outside the MCZ [푥̅In = 9.2 (range 5 – 14.7), 푥̅Out = 8.9 (range 6 – 12); W = 79, p = 0.79].

3.2.2 A4.1/4.2 High/Moderate energy circalittoral rock The habitat ‘A4.1/4.2 High/Moderate energy circalittoral rock’ is characterised by caryophyllids, Alcyonium sp., Eunicella verrucosa, feather stars (Antedonidae), Serpulidae and arborescent sponges on a mixed faunal turf (Figure 8). Commonly observed taxa include bryozoans Cellaria sp., Pentapora foliacea, Celleporidae, Crisiidae and Smittinoidea, hydroids Nemertesia spp., and Aglaopheniidae as well as the jewel anemone Corynactis viridis. The arborescent sponges comprise a number of species including Axinellidae, Raspailia sp. and Stelligera sp. However, the three sponge taxa are very difficult to identify from images and for this reason should be treated as a morphospecies in this context.

An ANOSIM analysis comparing community composition in still images acquired from the circalittoral rock habitat during 2014-2015 inside and outside the MCZ indicated a small but significant difference (Global R = 0.039, p = 0.002).

No differences were observed however in the number of taxa (S) between still images acquired across the circalittoral rock habitats inside and outside the MCZ [푥̅In = 9.2 (range 4 – 15), 푥̅Out = 9.2 (range 6 – 12.7); W = 181.5, p = 0.88].

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Kelp and red seaweeds (moderate energy infralittoral rock) (IR.MIR.KR)

Foliose red seaweeds with dense Dictyota dichotoma and/or Dictyopteris membranacea on exposed lower infralittoral rock (IR.HIR.KFaR.FoR.Dic)

Figure 7. Example images of biotopes observed to be associated with the infralittoral rock feature at The Manacles MCZ.

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Echinoderms and crustose communities (CR.MCR.EcCr)

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Eunicella verrucosa and Pentapora foliacea on wave-exposed circalittoral rock (CR.HCR.XFa.ByErSp.Eun)

Figure 8. Example images of biotopes observed to be associated with the circalittoral rock feature at The Manacles MCZ.

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3.3 Subtidal sedimentary BSH: Sediment composition and biological communities

Results are presented for sediment samples where both particle size distribution and infaunal community analyses were conducted (n = 59; 2015 survey). Table 3 shows the number of samples collected from the sedimentary Broadscale Habitats to which they were assigned. Too few samples were acquired from the ‘A5.1 Subtidal coarse sediment’ and ‘A5.2 Subtidal sand’ features to allow robust comparisons within and between treatments, thus descriptive statistics are presented in the absence of statistical analyses.

The percentage contribution of gravel, sand and mud for each sediment sample is presented in Figure 9. Each sediment distribution is labelled with its assigned sedimentary Broadscale Habitat. The distribution of sediment samples collected at The Manacles MCZ, along with their percentage contribution of gravel, sand and mud is illustrated in Figure 10.

In total, 615 taxa were identified from sediment samples collected in 2015. 84 % of infauna taxa were found within the site boundary and 129 taxa were solely found there. The total number of taxa identified from sediment samples assigned to each BSH is presented in Table 5 below.

Table 5. The total number of taxa found within and outside of the site boundary for each sedimentary Broadscale Habitat.

Broadscale Habitat (BSH) Number of taxa present In Out A5.1 Subtidal coarse sediment 281 247 A5.2 Subtidal sand 104 88 A5.4 Subtidal mixed sediments 442 416

ANOSIM analysis indicated that the epifaunal community observed in still images acquired from the ‘A5.2 Subtidal sand’ feature differs from that observed in association with both the ‘A5.1 Subtidal coarse sediment’ feature (large dataset pairwise R = 0.667, p = 0.001, small dataset R = 0.451, p = 0.001) and the ‘A5.4 Subtidal mixed sediments’ feature (large dataset pairwise R = 0.485, p = 0.001, small dataset R = 0.423, p = 0.001). However, there was no significant difference in the epifaunal communities associated with the ‘A5.1 Subtidal coarse sediment’ feature compared to that associated with the ‘A5.4 Subtidal mixed sediments’ feature (large dataset pairwise R = 0.034, p = 0.002, small dataset R = 0.033, p = 0.093). The main differences in epifaunal communities between the sand and coarse/mixed sediment features were due to the occurrence of ophiuroid and amphiurid brittle stars as well as polychaete casts observed almost exclusively in association with ‘A5.2 Subtidal sand’, whilst ‘A5.1 Subtidal coarse sediment’ and ‘A5.4 Subtidal mixed sediments’ were largely characterised by a variety of encrusting bryozoan and hydroid fauna, which were largely absent from ‘A5.2 Subtidal sand’.

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Figure 10. Distribution of sediment fractions at grab sample locations.

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3.3.1 Subtidal coarse sediment There were too few benthic macrofauna grab samples collected from the ‘A5.1 Subtidal coarse sediment’ feature to allow a robust statistical analysis to be carried out (12 samples in total; seven within and five outside of the MCZ boundary). It is therefore not possible to list characterising species of this BSH. Average within- group similarity was low, at 35.0%. 41% (256/620) of the taxa encountered in 2015 were present in ‘A5.1 Subtidal coarse sediment’ samples inside the site boundary. Similarly, 38% (233/620) of taxa were present outside the site.

Epifauna observed in still images acquired from the ‘A5.1 Subtidal coarse sediment’ feature include encrusting bryozoans and coralline algae, bryozoan and hydroid turf serpulid and chaetopterid worms, and occasional observations of red algae (Figure 11).

Infralittoral coarse sediment (SS.SCS.ICS)

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Circalittoral coarse sediment (SS.SCS.CCS)

Figure 11. Example images of fauna observed to be associated with the coarse sediment feature at The Manacles MCZ. An ANOSIM analysis comparing epifaunal community composition of ‘A5.1 subtidal coarse sediment’ stills collected during 2014-2015 from locations inside and outside the MCZ showed a slight difference (Global R = 0.237, p = 0.001). This is due to differences in the relative abundances of the main characterising taxa associated with this sedimentary feature.

A small, but significant increase was also observed in the average number of taxa recorded per still image acquired from the coarse sediment feature located inside the MCZ compared to those located outside [푥In = 6.4 (range 1.5 – 12.9), 푥̅Out = 4.2 (range 1 – 8.4); W = 417, p = 0.009]. The number of coarse sediment stations sampled inside the MCZ is, however, over twice that sampled outside (38 and 15 respectively), therefore the higher number of taxa observed in samples acquired inside the MCZ may be a result of the imbalance of sampling effort between the two treatments.

3.3.2 Subtidal sand There were too few grab samples assigned to ‘A5.2 Subtidal sand’ to allow robust statistical analyses to be carried out on benthic macrofauna (six samples in total; equal split within and outside of the designated boundary). The samples were also

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extremely variable, with the average within-group similarity being 18.6%. It is therefore not possible to list characterising species of this BSH. 13% (83/620) of all taxa present in 2015 were represented in ‘A5.2 Subtidal sand’ within the site boundary and 13% (82/620) outside.

Epifauna observed in still images of the ‘A5.2 Subtidal sand’ feature include Amphiuridae (Ophiuroidea), bivalves, occasional bryozoan turf and serpulid worms, and a number of unidentified wormcasts. However, many stills of clean sand contained no epifauna (Figure 12).

Subtidal sand (SS.SSa)

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Arenicola marina in infralittoral fine sand or muddy sand (SS.SSa.IMuSa.AreISa)

Amphiura brachiata with Astropecten irregularis and other echinoderms in circalittoral muddy sand (SS.SSa.CMuSa.AbraAirr)

Figure 12. Example images of fauna observed to be associated with the subtidal sand feature at The Manacles MCZ.

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There is, however, no observed difference in the average number of taxa (S) recorded per still between those acquired from the ‘A5.2 Subtidal sand’ feature located inside and outside the MCZ [푥̅In = 2.3 (range 1 – 8), 푥̅Out = 2.9 (range 1.5 – 6); W = 32, p = 0.22].

An ANOSIM analysis comparing the epifaunal community composition of ‘A5.2 Subtidal sand’ derived from still images collected during 2014-2015 inside and outside the MCZ showed a difference in observed taxa (Global R = 0.315, p = 0.001). The difference is due to sand inside the MCZ being mainly characterised by Amphiuridae (Ophiuroidea) and bivalves, with the ‘A5.2 Subtidal sand’ feature located outside the MCZ, which comprised slightly coarser sediment fractions, being characterised by areas of bryozoan turf along with serpulid worms and no observations of ophiuroids.

3.3.3 Subtidal mixed sediments 81% of benthic infaunal taxa encountered in the grab samples collected in 2015 were represented in samples from ‘A5.4 Subtidal mixed sediments’ (n = 41). 67% (415/620) of all taxa present were found in ‘A5.4 Subtidal mixed sediments’ within the site boundary and 64% (394/620) were found outside. The top ten taxa contributing to within-group similarity are listed in Table 6, however it should be noted that the similarity was low (38.8%), and therefore these taxa should not be considered to definitively characterise this BSH.

Table 6. Top ten taxa contributing to similarity (38.8%) within the ‘A5.4 Subtidal mixed sediments’ group (n=41). Average Average % Cumulative % Taxon Similarity/ Abundance Similarity St. Dev. Contribution Contribution Lumbrineris 4.75 2.86 3.24 7.37 7.37 cingulate (agg) Mediomastus 4.60 2.56 2.35 6.58 13.95 fragilis Timoclea ovata 3.28 1.15 1.16 2.95 16.9 Notomastus 2.05 1.06 1.72 2.72 19.62 Nemertea 1.91 1.00 2.11 2.58 22.2 Ampelisca spinipes 1.73 0.96 1.40 2.46 24.67 Polycirrus 1.92 0.94 1.73 2.41 27.08 Epizoanthus couchii 2.64 0.76 0.80 1.94 29.02 Scalibregma 1.73 0.74 0.87 1.91 30.93 inflatum Glycera lapidum 1.70 0.72 1.25 1.84 32.77

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Significantly more taxa were present in ‘A5.4 Subtidal mixed sediments’ grab samples collected from within the MCZ compared to those collected outside the site [푥̅In = 110 (range 56 – 149), 푥̅Out = 82 (range 56 – 120); W = 313, p = 0.006]. This was supported by similar observations of Margalef’s species richness being significantly higher for ‘A5.4 Subtidal mixed sediments’ sampled within the MCZ relative to those sampled outside the site boundary [푥̅In = 13.55 (range 8.45 – 17.44), 푥̅Out = 10.96 (range 7.58 – 13.29); W = 327, p = 0.001. Furthermore, there were significantly more individuals present in ‘A5.4 Subtidal mixed sediments’ samples collected from the mixed sediments feature located inside the designated site boundary compared to those collected outside [푥̅In = 458 (range 184 – 1251), 푥̅Out = 244 (range 132 – 439); W = 322, p = 0.0003]. There was no significant difference in the Shannon (Loge) diversity index values derived from ‘A5.4 Subtidal mixed sediments’ samples collected from inside the MCZ boundary when compared to those collected from the same ‘A5.4 Subtidal mixed sediments’ feature located outside the MCZ [푥̅In = 3.6 (range 2.8 – 4.1), 푥̅Out = 3.4 (range 2.7 – 3.7); W = 279, p = 0.06]. However, the Shannon diversity metric appears slightly higher in ‘A5.4 Subtidal mixed sediments’ samples collected from within the site boundary. Similarly, Hill’s diversity index (N1), although not significant, appears higher in ‘A5.4 Subtidal mixed sediments’ samples collected from within the site boundary [푥̅In = 37 (range 15.7 – 59.4), 푥̅Out = 31 (range 14.2 – 40.1); W = 279, p = 0.06].

Epifaunal communities observed in still images acquired in association with the ‘A5.4 Subtidal mixed sediments’ do not differ from those observed in association with ‘A5.1 Subtidal coarse sediments’ at the site (Figure 11 and Figure 13).

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Infralittoral mixed sediment (SS.SMx.IMx)

Circalittoral mixed sediment (SS.SMx.CMx)

Figure 13. Example images of fauna observed to be associated with the subtidal mixed sediments feature at The Manacles MCZ.

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An ANOSIM analysis comparing community composition derived from still images acquired from the ‘A5.4 Subtidal mixed sediment’ feature during 2014-2015 located inside and outside the MCZ showed no significant difference in observed taxa (Global R = 0.023, p = 0.059).

A comparison of the average number of taxa (S) recorded per still image shows there is on average one more taxon observed per still outside the MCZ than inside. [푥̅In = 4.5 (range 1 – 9), 푥̅Out = 5.6 (range 1.3 – 11); W = 616.5, p = 0.03].

3.3.4 Subtidal macrophyte-dominated sediment The subtidal macrophyte-dominated sediment EUNIS habitat classification includes ‘Seaweed dominated mixed sediments’, ‘Seagrass beds’, ‘Lagoonal angiosperm communities’ and ‘Maerl beds’. Two components of this Broadscale Habitat classification were observed at The Manacles MCZ, ‘Red seaweeds and kelps on tide-swept mobile infralittoral cobbles and pebbles’ (SS.SMp.KSwSS.LsacR.CbPb , 42 stills) and ‘Maerl beds’ (SS.SMp.Mrl, 45 stills) (Figure 14). ‘A5.5 Subtidal macrophyte dominated sediment’ and its constituent biotopes were only recorded as present inside the MCZ.

However, a closer investigation of the data indicates a difference between assignation of the two biotopes and ‘A5.5 Subtidal macrophyte-dominated sediment’ in the various data sets. In both the 2012 and 2016 datasets, the ‘Maerl beds’ biotope and BSH ‘A5.5 Subtidal macrophyte-dominated sediment’ has been assigned to stills with dead and live Maerl on coarse or mixed sediments. In the 2014 and 2015 data sets these are included in coarse and mixed sediment biotopes and assigned the corresponding BSH. Similarly, ‘Red seaweeds and kelps on tide- swept mobile infralittoral cobbles and pebbles’ have only been recorded in the 2015 and 2016 datasets. In the 2014 and 2015 data sets a distinction between ‘algae present’ and ‘frequent to abundant algae’ has been made by classifying the former into ‘Infralittoral coarse sediment’ and latter into ‘Red seaweeds and kelps on tide- swept mobile infralittoral cobbles and pebbles’. No stills with the higher abundance of algae were present in the 2014 data set. In the 2012 dataset, all coarse substrate with algae, regardless of abundance, has been recorded as ‘Infralittoral coarse sediment’, and hence grouped into ‘A5.1 Subtidal coarse sediment’. No abundance data exists for the 2016 data set.

No further analysis has been carried out on the ‘Red seaweeds and kelps on tide- swept mobile infralittoral cobbles and pebbles’ as a result of the inconsistency in classification of the seabed imagery data. A more detailed analysis of the distribution and status of the Maerl feature within The Manacles MCZ is provided in the following section of the report.

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Red seaweeds and kelps on tide-swept mobile infralittoral cobbles and pebbles (SS.SMp.KSwSS.LsacR.CbPb)

Maerl beds (SS.SMp.Mrl)

Figure 14. Example images of the subtidal macrophyte-dominated sediment feature at The Manacles MCZ.

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3.4 Habitat Features of Conservation Importance (FOCI)

3.4.1 Maerl beds Maerl was observed in 236 still images acquired across the BSH. The majority of the Maerl observed in images is dead, with live Maerl recorded in 88 stills. The percentage cover of Maerl in single images also consists primarily of dead Maerl (1- 79%), with the percentage cover of live Maerl observed ranging from 1-8%. Combined Maerl coverage over 20% is observed almost exclusively in association with the ‘A5.5 Subtidal macrophyte-dominated sediment’ and ‘A5.4 Subtidal mixed sediments’ (Table 7). Figure 15 illustrates the locations where Maerl was observed in still images.

Table 7. Number of still images with Maerl recorded in each Broadscale Habitat (BSH). Values are provided for observations of dead Maerl, live Maerl and where the total percentage cover of Maerl exceeds 20%.

Number of records in still images

A3.2 A4.2 A5.1 A5.2 A5.4 A5.5 Dead Maerl 0 7 40 0 139 45 Live Maerl 0 0 13 0 26 49 Total Maerl >20 % coverage 0 0 1 0 17 37

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Figure 15. Percentage cover of dead and live Maerl observed in still images.

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Figure 16. Acoustic signatures in side-scan sonar data identified in conjunction with Maerl. Symbols indicate relative percentage cover of live (pink) and dead Maerl (brown) in the still images acquired in association with the sidescan sonar data. The side-scan sonar data acquired around The Manacles were plotted in GIS together with Maerl observations in the still images. Acoustic signatures were investigated in locations where Maerl (dead and alive) was observed. The analysis revealed that although some live Maerl was observed in association with more consolidated coarse sediments, deposits of (mainly dead) Maerl fragments were

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associated with visible sediment wave formations (Figure 16, note the sandwave bedforms illustrated are oriented horizontally, whilst a number of artefacts in the acoustic data are also visible, which are oriented perpendicular to the sandwave features). Hence, it was possible to identify regions of possible Maerl deposits by outlining the sediment waves observable in the side-scan sonar imagery. Not all areas with sediment waves were observed to contain Maerl, however. Figure 17 shows areas where sediment waves are present. The sediment wave fields have further been classified according to presence or absence of Maerl in co-occurring still images and where no still images were available.

It was not possible to carry out a comparison of the infaunal communities associated with the subtidal sediments containing live or dead Maerl using the grab sample data as the presence of dead Maerl was not recorded consistently as part of the grab sample processing. Lithothamnion glaciale was present in the sediment samples collected from two stations (MNCL053 ‘A5.1 Subtidal coarse sediment’ and MNCL021 ‘A5.4 Subtidal mixed sediments’). The species Lithothamnion glaciale is listed as a Maerl species on the Marine Life Information Network (MarLIN) online resource. However, L. glaciale is not included in Table 8 of the ENG which lists two different Maerl species; Lithothamnion corallioides, which is nationally scarce, and Phymatolithon calcareum.

Figure 15 and Figure 17 indicate potential locations for future, targeted assessment and monitoring of the habitat FOCI ‘Maerl bed’ should it be required to improve our understanding of the current status of the ’Maerl bed’ feature present within The Manacles MCZ in the context of its wider distribution (and condition) across the south-west coast of England.

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3.5.1 Pink Sea-Fan (Eunicella verrucosa) At The Manacles MCZ the species FOCI Eunicella verrucosa is primarily present in association with the ’A4.1/4.2 High/Moderate energy circalittoral rock’ feature, with individuals observed to be attached to cobbles and boulders in stable coarse and mixed sediments. E. verrucosa was also observed in three still images that were classified as infralittoral rock. These were, however, at a depth greater than 21 m, where other rock is classified as circalittoral. The infralittoral rock classification is a result of brown algae observed to be present in the still images. However, it is not

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clear if the algae are attached. Consequently, for the purposes of this analysis the samples were treated as being representative of circalittoral rock. For monitoring purposes, it is sufficient to evaluate the occurrence and abundance of E. verrucosa in association with the ‘A4.1/4.2 High/Moderate energy circalittoral rock’ feature.

The maximum number of individuals observed in a single still image was ten. The highest mean number of individuals per still image at a station was six. The mean number of individuals per still image is significantly higher outside of the MCZ than inside [푥̅In = 0.87 (range 0 – 6), 푥̅Out = 1.57 (range 0 – 4.2); W = 156, p = 0.04].

Figure 18. Mean counts per station of Eunicella verrucosa individuals per still image for each BSH. The maximum density observed in a single video segment was 3.3 individuals m-2. There is no significant difference in E. verrucosa density observed between stations located inside and outside of the MCZ [푥̅In = 0.6 (range 0 – 3.3), 푥̅Out = 0.3 (range 0 – 0.99); W = 55.5, p = 0.8]. The high mean value from video segments acquired inside the MCZ is due to three transects located in the northern part of the MCZ having very high densities of E. verrucosa (Figure 21). Those high densities are not captured in the still images collected from the same transects (Figure 20).

Figure 19. Density of Eunicella verrucosa (individuals/m2) in video segments for each BSH.

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Figure 20. Number of Eunicella verrucosa individuals observed in each still image.

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Figure 21. Abundance of Eunicella verrucosa in video transect segments represented using the SACFOR abundance scale.

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3.5.2 Other Species FOCI Sea-Fan Anemone (Amphianthus dohrnii) were observed in two stills. No observations of the Spiny Lobster (Palinurus elephas) or Stalked Jellyfish (Haliclystus auricula) were made in any of the samples collected as part of the surveys reported here. The surveys reported here were not designed to specifically monitor (or identify the presence of) species FOCI. As such, this should not be interpreted as an absence of these species FOCI from the site.

3.6 Non-indigenous species (NIS)

Three non-indigenous species were identified from the infaunal samples. A total of 221 individuals of the polychaete worm Goniadella gracilis, were identified from 61% (36/59) of infaunal samples. A small barnacle (Hesperibalanus fallax) native to the Atlantic coast of tropical Africa, which is considered to have extended its range as far north as the Netherlands and has been recorded from the southwest coast of England and Wales, was also present in 13 samples. Finally, five juveniles of the slipper limpet (Crepidula fornicata), which is a gastropod mollusc first introduced to the UK in association with imported oysters (Crassostrea virginica) between 1887 – 1890 (Eno et al., 1997), were found in four samples. The average biomass (blotted dry wet weight) of these individuals was 0.0005 g (range 0.0001 – 0.0016 g). Figure 22 shows the location of grab samples with non-indigenous fauna.

There were no non-indigenous taxa observed in the still images.

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Figure 22. Location of grab samples where non-native species were observed.

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3.7 Supporting processes 3.7.1 Hydrodynamics: tidal energy and exposure The site faces away from the prevailing westerly winds and mainly has moderate (0.5-1.5 m s-1) to weak (< 0.5 m s-1) tidal currents flowing on a southwest-northeast axis (Figure 23). The tidal model of The Manacles MCZ area highlights the sheltered nature of the shallow bays and indicates the highest mean current velocities and mean bed shear stress at the site occur in association with the shallow, rock features within the site. The outputs of the model indicate that the rock habitat occurs in an area of moderate energy. A high energy environment, characterised by strong (1.5- 3 m s-1) currents, is only present at maximum velocities over the spring-neap tidal cycle in a very limited area. It should be noted that this model does not include wind and wave energy, and therefore does not provide a complete indication of hydrodynamics. In particular it is acknowledged that wave action at shallower depths will be altering the energy conditions experienced by the communities present and therefore this modelling will not resolve these small scale changes in energy regime.

3.7.2 Water quality parameters No water quality parameters were monitored at this site during the surveys reported here.

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3.7.3 Sediment quality parameters No sediment quality parameters were monitored at this site during the surveys reported here.

3.8 Additional monitoring requirements

3.8.1 Marine litter Observations of marine litter in the seabed imagery data were categorised and recorded according to the protocol provided in Annex 4. Incidences of litter present on the seabed were observed in the seabed imagery at five stations, consisting of the MSFD litter categories Plastic Sheet (A2), Synthetic Rope (A7), Plastic Pipe (A14), and Other (F5) unidentified litter. The locations of the litter are shown in figure 24.No marine litter assessment was carried out on the sediment samples collected at The Manacles MCZ.

Figure 24. Locations of litter classified by MSFD categories from still imagery, within The Manacles MCZ.

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4 Discussion This baseline monitoring report provides the initial temporal characterisation of designated features within The Manacles MCZ along with a similar characterisation of comparable features out with the site boundary. Any statements or interim conclusions on feature condition or ecological status provided in this report are underpinned by the evidence collected, collated and analysed herein. Formal assessment of the condition status of designated features is carried out for this MCZ by Natural England using all available data. 4.1 Subtidal rock BSH: Extent, distribution, physical structure and biological communities The physical structure of the subtidal rock features in The Manacles MCZ comprise bedrock overlain by boulders and cobbles. The biological communities of the subtidal rock habitats in The Manacles MCZ are typical for this region of the southwest coast. Although two BSHs were identified during analysis of the still imagery (i.e., moderate and high energy regimes assigned to the rock features), the physical information from the site and results of the biological community analysis does not support any delineation between energy categories within these data. The majority of the instances of ‘high energy’ BSH were classified based on the presence of a small number of key fauna characteristic of higher energy regimes within communities otherwise statistically indistinguishable from those classified as ‘moderate energy’.

As it has been shown not to be feasible to delineate the fine scale changes in energy regimes within the infralittoral or circalittoral rock habitats the subtidal rock BSH in the Manacles MCZ should not be split by energy regime into component features for characterisation and future monitoring purposes. All instances of ‘infralittoral rock’ and ‘circalittoral rock’ have instead been incorporated here into the composite habitats ‘A3.1/3.2 High/Moderate energy infralittoral rock’ and ‘A4.1/4.2 High/Moderate energy circalittoral rock’.

No significant differences in community composition or the number of taxa were observed between the infralittoral and circalittoral rock features located inside and outside of the MCZ boundary. This indicates that the selected ‘control’ sites outside the MCZ are suitable for the purpose of future monitoring of these features. As a result of not having a detailed habitat map available at the planning stage of the characterisation survey, the large majority of video transects intended to target the rock features were placed on sedimentary habitats. The habitat map presented as part of this report, will enable the subsequent placement of additional video transects which more effectively target the rock BSH if required for future assessment and monitoring.

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4.2 Subtidal sedimentary BSH: Extent, distribution, sediment composition and biological communities As with the rock features, the biological communities of the subtidal sediments in The Manacles MCZ are typical for this region of the southwest coast. Sediment samples collected within and outside of the site boundary were assigned to one of three sedimentary broad scale habitats: ‘A5.1 Subtidal coarse sediment’, ‘A5.2 Subtidal sand’ or ‘A5.4 Subtidal mixed sediments’. Biological characterisation was possible only using samples collected during the 2015 survey, which were processed for macrofauna as well as for sediment particle size. The majority of sediment samples collected during the 2015 survey were classified as ‘A5.4 Subtidal mixed sediments’.

The results of statistical testing indicated that the ‘A5.4 Subtidal mixed sediments’ sampled within the MCZ were characterised by a higher number of infaunal taxa and had a higher abundance of enumerable infauna than those sampled outside of the MCZ boundary. Both diversity metrics assessed also indicated slightly higher values inside the MCZ, but the results of statistical testing showed the differences to be insignificant at a P<0.05. High within Broadscale Habitat variability was also observed for the ‘A5.4 Subtidal mixed sediments’ present in and around The Manacles MCZ.

Results from the analysis of still image data indicated slightly higher numbers of epifaunal taxa to be associated with ‘A5.4 Subtidal mixed sediments’ located outside the MCZ when compared to those located inside. Conversely, a higher number of taxa were recorded in association with ‘A5.1 Subtidal coarse sediment’ located inside the MCZ in comparison to those located outside the site. It should be noted that, both for infauna and epifauna, observed differences in the derived values of a number of univariate diversity metrics may be attributable to an imbalance in the level of survey effort carried out across features located within the site relative to that conducted outside the MCZ. The use of sediment classifications as a proxy for epifaunal communities (e.g., coarse and mixed sediments) is also questionable as community characteristics are observed to vary considerably within a single BSH category. The similarity of epifaunal communities across ‘A5.1 Subtidal coarse sediment’ and ‘A5.4 Subtidal mixed sediments’ further indicates that the differences observed may be artefacts of an imbalanced survey design.

Still images indicate at least three different sand biotopes to be present within The Manacles MCZ. These comprise a clean sand, and two muddy sand biotopes, one with burrowing brittle stars, the other with large polychaete casts. In order to comprehensively characterise the ‘A5.2 Subtidal sand’ feature, more targeted and extensive sampling is required. The habitat map presented in this report will help to achieve this by allowing a more targeted and balanced statistical design to be applied for future assessment and monitoring. ‘A5.1 Subtidal coarse sediment’ and ‘A5.4 Subtidal mixed sediments’ were too acoustically similar to separate reliably in

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the habitat map. Hence, it is not possible to identify separate locations for additional future sampling of these two sedimentary BSH. Sediment samples collected at the same stations in 2012 and 2015 also suggest that the two habitats may not be temporally stable and as such may not be suited as sentinel stations for long term monitoring. Out of eleven stations, six exhibited sufficiently different particle size distributions between 2012 and 2015 samples to be classified as different BSH. However, without representative replication of samples at each station, it is not possible to determine if the change is a result of temporal change or fine scale spatial variability. For example, whilst the samples collected during the two sampling occasions were considered to be representative of the same station, in reality the two samples were collected from two different areas of seabed, approximately 76 m apart. 4.3 Habitat Features of Conservation Importance (FOCI) The habitat FOCI ‘Maerl Beds’ observed to be present at this site comprises part of the subtidal mixed sediment BSH feature (Figure 15). The GMA for this habitat FOCI within this site is to recover it to favourable condition. Abrasion pressure, in the form of demersal trawling and scallop dredging, has been shown to result in the removal of living Maerl from the seabed and a reduction in habitat stabilising algae. This has been shown to negatively affect the associated biological community structure (Hall-Spencer, 1995; Hall-Spencer, 1998). The Manacles MCZ is not believed to have been heavily fished historically. A low intensity of scallop dredging by small (<12 m) vessels is known to have occurred across the eastern half of the site, mostly located east of Maen Garrick and south of Maen Voes (pers. comm. Colin Trundle, CIFCA). A byelaw prohibiting the use of all bottom towed fishing gear within the MCZ is currently in place. The cessation of use of all bottom fishing gear within the MCZ is expected to help the Maerl feature recover.

Whilst the surveys, that provided the data reported here, were not designed to specifically assess and monitor the condition of the Maerl habitat feature, the evidence provided of a relatively locally restricted distribution of the Maerl bed within the MCZ, which is comprised primarily of dead Maerl, supports the consideration of a management approach that would facilitate its potential recovery.

A number of studies have explored the characteristics of biological communities associated with Maerl features. Studies into the food web dynamics of Maerl beds off the coast of Brittany demonstrated that live Maerl beds in good condition, which exhibit a high degree of structural complexity, increase both the local diversity and the availability of prey species for higher trophic levels (Grall et al., 2006). The nearby Fal and Helford SAC contains the largest Maerl bed in England and the most south-westerly example in Britain. The two species of Maerl listed in the ENG are present within the Fal and Helford SAC alongside what is described as an ‘exceptionally diverse’ biological community (Natural England, 2000).

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The data in this report is not sufficient to fully evaluate the condition of the Maerl feature or to assess its value in The Manacles MCZ in the context of the Maerl present in the wider environment of the southwest of England. However, a number of approaches may be considered for future monitoring, which will allow a more effective assessment of the condition of the Maerl feature. These include: 1) reliable estimation of the spatial extent and distribution of the Maerl bed features within the MCZ, 2) investigation of the composition and condition of the Maerl species population of which the Maerl beds are comprised, and 3) assessment of the functional role of the Maerl beds and their ability to support a locally diverse associated faunal assemblage.

The Maerl beds within The Manacles MCZ have not been specifically sampled to identify the Maerl species which comprise the Mearl bed feature. Sediment samples collected from two stations were found to contain the Maerl species Lithothamnion glaciale, which is not included in the list of Maerl species associated with this habitat FOCI in the ENG document. However, this does not exclude the presence of the other species of Maerl, which are listed in the ENG. A more extensive sampling campaign may be required to confirm the full range of Maerl species present. Any destructive sampling of Maerl may have deleterious impacts and must be risk assessed prior to any survey operations commencing. However, comparison of the percent coverage of dead and live Maerl in still images acquired over the known Maerl features will enable some assessment of the condition of the Maerl. For future monitoring, the application of a sufficiently comprehensive and targeted survey design for the collection of seabed imagery data in association with the Maerl bed features may allow a more effective assessment of the condition of these features in the context of background natural variability.

In order to assess the functioning of the Maerl features present within The Manacles MCZ (e.g., as a habitat resource for colonisation by other taxa), a specific sampling design is required to compare the composition and diversity of the fauna associated with the Maerl features relative to those present in association with the surrounding mixed sediments.

Whilst acoustic signatures can be identified in the sidescan sonar data which are coincident with areas of Maerl identified in the seabed imagery, it is not possible to use these remote sensing data to reliably estimate the distribution and spatial extent of the feature within the MCZ. Furthermore, it is not possible to determine how stable the Maerl occurrences are at The Manacles MCZ. More detailed investigation (e.g., using diver transects traversing known occurrences, or potentially photo- mosaics on specific identifiable sections of the Maerl bed) would be required to define the edges of the patches and effectively monitor changes in their spatial extent over time.

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4.4 Species Features of Conservation Importance (FOCI) The characterisation data reported here provides evidence of the presence and relatively high densities of the ‘Pink Sea-Fan (Eunicella verrucosa)’ in association with the ‘A4.1/4.2 High/Moderate energy circalittoral rock’ feature within The Manacles MCZ. The results in this report concur with the findings of a two-year study, which was carried out between 2001 to 2002 by Seasearch based on records of Sea-Fans provided by volunteer divers, which identified The Manacles MCZ as one of the areas with the densest populations in the south-west region of the UK (Wood, 2003). A method is also described by which recovery of this species FOCI could be monitored as part of an ongoing monitoring programme designed to assess the efficacy of management measures implemented at this site.

No observations were made of the other species FOCI designated for protection with this MCZ, namely the ‘Spiny Lobster (Palinurus elephas)’ and the ‘Stalked Jellyfish (Haliclystus auricula)’ in any of the samples collected as part of the surveys reported here. However, as the surveys were not designed to specifically monitoring species FOCI, this should not be interpreted as an absence of these species from the site.

4.5 Non-indigenous species (NIS)

Three non-indigenous species were identified from the infaunal samples. The polychaete worm Goniadella gracilis was the most prevalent non-indigenous species recorded in infaunal samples collected at The Manacles MCZ, with 221 individuals being recorded from 61% of the samples. The small barnacle Hesperibalanus fallax, native to the Atlantic coast of Africa, was also observed in 13 of the infaunal samples. Finally, five juveniles of the slipper limpet Crepidula fornicata, a NIS first observed in UK waters in 1887, when they were introduced in association with the imported oyster species Crassostrea virginica, were recorded from four infaunal samples.

4.6 Supporting processes

The results of hydrodynamic modelling indicated that The Manacles MCZ is subject to relatively moderate energy levels due to it being largely sheltered from the prevailing westerly winds, with maximum tidal currents of 1.5 m s-1. This modelling does not include wave action however which it is acknowledged that at shallower depths will be altering the energy conditions experienced by the communities present and therefore is not able to resolve these small-scale changes in energy regime. Water quality and sediment quality parameters were not included as part of the surveys which inform this report.

4.7 Additional monitoring requirements

Ten items of marine litter on the seabed were observed in the still images acquired at the site and these included fragments of rope and plastic sheets.

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5 Recommendations for future monitoring The report highlights the limitations of applying a survey design which is not informed by reliable information relating to the location and distribution of the conservation features of interest within and adjacent to the site (e.g., through use of a sufficiently resolute and accurate seabed habitat map).

• In this instance, the lack of availability of a habitat map for use in survey planning has resulted in the following limitations relating to subsequent data analyses and statistical testing which, in turn, can lead to misinterpretation of the results: - Insufficient sampling of all features of conservation interest present within and adjacent to the MCZ; and - Imbalance in sampling design between treatments (e.g., habitat features, protected versus unprotected examples of comparable features). Recommendations to mitigate against the limitations identified in the current report during future monitoring include:

• Future monitoring survey designs should be informed using a sufficiently accurate and resolute habitat map which covers the site and features of interest, along with comparable areas of seabed in the wider environment and adjacent to the site.

• Designated features within the MCZ should be prioritised for future monitoring using a risk based approach. Where all features within an MCZ are selected for monitoring, and time and budgets are limited, power of detection can be lost where resources are directed at monitoring across the entire site. - Future monitoring should consider a series of ‘sentinel’ monitoring stations for lower risk/lower priority features, with more targeted investigative monitoring for higher risk/higher priority features e.g., mixed/coarse sediments and/or Maerl beds in this instance. - Monitoring should, where possible, be aligned with other monitoring programmes (e.g., relating to WFD Ecological Quality assessment and SAC Favourable Conservation Status monitoring) on a regional basis to optimise synergies and achieve the necessary efficiencies.

• Further studies are required to improve our understanding of the observed variability (spatial and temporal) in biological assemblages found in association with given habitat features. For example, classification of infaunal communities in alignment with the four possible sedimentary BSHs is not necessarily ecologically relevant. This is because biological communities do not necessarily align with the same physical thresholds used in the classification of sedimentary BSHs according to EUNIS.

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• Specific recommendations for future monitoring of Eunicella verrucosa include: - The condition and recovery of this species could be assessed as part of an ongoing monitoring programme (using a BACI experimental approach) designed to assess the efficacy of the management measures implemented at this site. - The survey design applied should include consideration of methods for the effective sampling of patchy features (both habitats and species). For example, information on feature patchiness will act to improve both the design and analysis of future monitoring work, thereby reducing the potential for ‘Type I’ (‘false positive’) and ‘Type II’ (‘false negative’) errors in statistical hypothesis testing. - Standardisation of still and video imagery data to known area coverage (field of view and length of tow) is required for robust time-series comparison of abundance.

• Specific recommendations for future monitoring of Maerl features include: - Given the limitations of acoustic remote sensing approaches for delineating Maerl features from surrounding sediments, alternative approaches should be considered (e.g., acquisition of full coverage photo- mosaics). - Undertake specific studies to improve the understanding of differences between live/dead Maerl features as habitats for associated biological assemblages (e.g., how does the conservation status of the Maerl feature relate to its biological condition and ecological functioning)? - Ensure an assessment of the Maerl component of infaunal samples is included as part of the protocol for sample processing. For example, volume and status (live/dead at time of sampling) of Maerl present in the sample.

• Specific recommendations for monitoring of supporting processes include: - Make optimal use of wider monitoring data (e.g., acquired as part of existing integrated marine monitoring programmes) to provide the context in relation to wider ecosystem processes operating at a landscape or regional sea scale.

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6 References

Arnold, K. (2016). The Manacles MCZ 2015 Survey Report. 136 pp.

Astrium (2011). Creation of a high resolution Digital Elevation Model (DEM) of the British Isles continental shelf: Final Report. Prepared for Defra, Contract Reference: 13820. 26 pp.

Brown, L., and Mitchell, P. (2016). The Manacles MCZ Post-Survey Site Report. 90 pp.

Coggan, R., Mitchell, A., White, J. and Golding, N. (2007). Recommended operating guidelines (ROG) for underwater video and photographic imaging techniques www.searchmesh.net/PDF/GMHM3_video_ROG.pdf [Accessed 24/10/2016].

Clarke, K.R. and Gorley, R.N. (2006). PRIMER v6: User Manual/Tutorial. PRIMER- E, Plymouth, 192pp.

Elliott, M., Nedwell, S., Jones, N., Read, S.J., Cutts, N.D. and Hemingway, K.L., (1998). Volume II: Intertidal sand and mudflats and subtidal mobile sandbanks. An overview of dynamic and sensitivity characteristics for conservation management of marine SACs. UK Marine SACs project, Oban, Scotland. English Nature.

Eno, N.C., Clark, R.A. and Sanderson, W.G. (Eds.) (1997). Non-native marine species in British waters: a review and directory. Peterborough: Joint Nature Conservation Committee.

Folk, R.L. (1954). The distinction between grain size and mineral composition in sedimentary rock nomenclature. Journal of Geology, 62, 344-359.

Godsell. N., Fraser, M., and Jones, N. (2013). The Manacles rMCZ Survey Report. 60 pp.

Grall, J., Le Loc’h, F., Guyonnet, B. and Riera, P. (2006). Community structure and food web based on stable isotopes (δ15N and δ13C) analysis of a North Eastern Atlantic maerl bed. Journal of Experimental Marine Biology and Ecology, 338(1), 1- 15.

Hall-Spencer, J. M. (1995). The effects of scallop dredging on maerl beds in the Firth of Clyde. Porcupine Newsletter 6, 16-27.

Hall-Spencer, J. M. (1998). Conservation issues relating to maerl beds as habitats for molluscs. J. Conchology Special Publication, 2, 271-286.

Hothorn, T., Hornik, K. and Zeileis, A. (2006). Unbiased Recursive Partitioning: A Conditional Inference Framework. J. Comput. Graph. Stat. 15, 651–674.

JNCC (2004). Common standards monitoring guidance for littoral sediment habitats. Peterborough, JNCC.

Lieberknecht, L.M., Hooper, T.E.J., Mullier, T.M., Murphy, A., Neilly, M., Carr, H., Haines, R., Lewin, S. and Hughes, E. (2011). Finding Sanctuary final report and

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recommendations. A report submitted by the Finding Sanctuary stakeholder project to Defra, the Joint Nature Conservation Committee and Natural England. http://findingsanctuary.marinemapping.com/ Final report as one document (PDF, 43MB) - 14 September 2011 version [Accessed 18/02/2014].

Long, D. (2006). BGS detailed explanation of seabed sediment modified folk classification.

Mason, C. (2011). NMBAQC’s Best Practice Guidance Particle Size Analysis (PSA) for Supporting Biological Analysis.

MNCR (1990). SACFOR abundance scale used for both littoral and sublittoral taxa from 1990 onwards. http://jncc.defra.gov.uk/page-2684 [Accessed 07/02/2018].

MSFD GES Technical Subgroup on Marine Litter. (2013). Guidance on Monitoring of Marine Litter in European Seas. Publications Office of the European Union. EUR 26113. http://publications.jrc.ec.europa.eu/repository/handle/JRC83985 [accessed 19/2/2017]

Natural England (2000). Fal and Helford SAC Regulation Conservation Advice Package. 77pp. available http://publications.naturalengland.org.uk/publication/3048654 [Accessed 07/02/2018].

Natural England (2010). The Marine Conservation Zone Project: Ecological Network Guidance. 144pp. http://jncc.defra.gov.uk/PDF/100705_ENG_v10.pdf [Accessed 08/08/2017].

Naylor, H., Trundle, C., Jenkin, A., Street, K., and Matthews, R. (2016). Manacles MCZ Drop Down Video (20160516_CIFCA_MCZ_MAN_DDV) Survey Field Report. 20 pp.

R Core Team (2015). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R- project.org/. [accessed 07/02/2018]

Soulsby, R., 1997. Dynamics of marine sands: a manual for practical applications. Thomas Telford.

Stebbing, P., Murray, J., Whomersley, P. and Tidbury, H. (2014). Monitoring and surveillance for non-indigenous species in UK marine waters. Defra Report. 57 pp.

Trundle, C., Matthews, R., Street, K., Naylor, H., and Jenkin, A. (2016). Manacles MCZ Sidescan (20160303_MCZ_MAN_SSS) Survey Field Report. 17 pp.

Wood, C. (2003). Pink sea fan survey 2001/2. A report for the Marine Conservation Society.

Worsfold, T.M., Hall., D.J. and O’Reilly, M. (2010). Guidelines for processing marine macrobenthic invertebrate samples: a processing requirements protocol version 1 (June 2010). Unicomarine Report NMBAQCMbPRP to the NMBAQC Committee. 33 pp.

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Annex 1. Infauna data truncation protocol. Raw taxon abundance and biomass matrices can often contain entries that include the same taxa recorded differently, erroneously or differentiated according to unorthodox, subjective criteria. Therefore, ahead of analysis, data should be checked and truncated to ensure that each row represents a legitimate taxon and they are consistently recorded within the dataset. An artificially inflated taxon list (i.e., one that has not had spurious entries removed) risks distorting the interpretation of pattern contained within the sampled assemblage.

It is often the case that some taxa have to be merged to a level in the taxonomic hierarchy that is higher than the level at which they were identified. In such situations, a compromise must be reached between the level of information lost by discarding recorded detail on a taxon’s identity and the potential for error in analyses, results and interpretation if that detail is retained.

Details of the data preparation and truncation protocols applied to the infaunal datasets acquired at The Manacles MCZ ahead of the analyses reported here are provided below:

• Where there are records of one named species together with records of members of the same genus (but the latter not identified to species level) the entries are merged and the resulting entry retains only the name of the genus.

• Taxa are often assigned as ‘juveniles’ during the identification stage with little evidence for their actual reproductive natural history (with the exception of some well-studied molluscs and commercial species). Many truncation methods involve the removal of all ‘juveniles’. However, a decision must be made on whether removal of all juveniles from the dataset is appropriate or whether they should be combined with the adults of the same species where present. For the infaunal data collected at The Manacles MCZ: where a species level identification was labelled ‘juvenile’, the record was combined with the associated species level identification, when present or the ‘juvenile’ label removed where no adults of the same species had been recorded.

• Records of meiofauna (i.e., nematodes) were removed.

• Records of fish species were removed.

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Annex 2. Epifauna data truncation protocol applied to seabed imagery data. Still image data were collated from multiple surveys carried out during 2012, 2014 and 2015. The data collected in 2012 were analysed separately to data collected in 2014 and 2015, which were analysed simultaneously as a combined dataset. On examination of the taxonomic notation used in analysing the stills acquired during the different surveys (2012 v. 2014 and 2015) the datasets exhibited differences between the taxonomic detail recorded, with more taxa assigned to lower levels (genera and species) in the more recently acquired data. In addition, the results of image analysis differed in relation to the level of taxonomic detail assigned to different still images. Consequently, two levels of truncation were used: 1) truncation to higher taxonomic level and consistent notation to combine 2012, 2014 and 2015 datasets and 2) truncation within the combined 2014 and 2015 datasets to reduce taxonomic uncertainty. Epifauna data preparation and truncation followed the steps detailed below:

Initially, all assigned taxon names were collated with accompanying counts of occurrences in each data set. All taxon names were linked to an entry in an aggregation matrix forming a truncation matrix that was used as a basis for decisions. The table below shows an extract of the truncation matrix used to reassign taxon labels. Uncertain and vague taxa (such as ‘Animalia crust’) and all fish were removed. Other taxa were combined to the highest common taxonomic level with some exceptions detailed below

The 2012 dataset comprised records of taxa at a less resolute level of identification. As a result, in the dataset combining all results of seabed image analyses using the data collected during all three surveys (2012 and 2014-2015), sponges and bryozoans, as well as red and brown algae were classified to morphotype, and all hydrozoans and ascidians grouped to Hydrozoa and Ascidiacea, respectively. Exceptions were made for very conspicuous, easily identifiable taxa that had been observed in several images across all survey datasets, such as the hydrozoan genera Nemertesia and Tubularia and laminarian algae. All other taxa were grouped to the highest common taxonomic level identified between the two lots.

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Extract from the epifauna truncation matrix. Levels 2-6 represent taxonomic level from genera to phyla in the aggregation matrix N12/N14/N15 = Number of observations in 2012/2014/2015. N = Total number of observations in combined dataset. Recorded taxon contains each unique entry from combined abundance matrices. Assigned taxon shows the taxon name after truncation.

Level 6 Level 5 Level 4 Level 3 Level 2 Recorded Taxon N12 N14 N15 N Assigned Taxon ANIMALIA ANIMALIA ANIMALIA ANIMALIA ANIMALIA AnimaliaCrust 0 0 8 8 Remove ANIMALIA ANIMALIA ANIMALIA ANIMALIA ANIMALIA Animaliaturf 0 22 39 61 Remove ANIMALIA ANIMALIA ANIMALIA ANIMALIA ANIMALIA Burrows 45 0 0 45 Remove ANNELIDA ANNELIDA ANNELIDA ANNELIDA ANNELIDA AnnelidaY 0 0 5 5 Remove ANNELIDA POLYCHAETA POLYCHAETA POLYCHAETA POLYCHAETA PolychaetaBurrow 0 3 0 3 Remove ANNELIDA POLYCHAETA PHYLLODOCIDA Polynoidae Polynoidae Polynoidae 1 0 0 1 Polynoidae ANNELIDA POLYCHAETA CAPITELLIDA Arenicolidae Arenicola Arenicola sp. (casts) 32 0 0 32 Polychaeta Cast ANNELIDA POLYCHAETA POLYCHAETA POLYCHAETA POLYCHAETA PolychaetaCast 0 11 0 11 Polychaeta Cast ANNELIDA POLYCHAETA POLYCHAETA POLYCHAETA POLYCHAETA Polychaeta (tube) 46 0 0 46 Polychaeta Tube ANNELIDA POLYCHAETA POLYCHAETA POLYCHAETA POLYCHAETA Polychaetatube 0 17 7 24 Polychaeta Tube ANNELIDA POLYCHAETA SABELLIDA Sabellidae Sabella Sabella pavonina 0 0 7 7 Sabellidae ANNELIDA POLYCHAETA SABELLIDA Sabellidae Sabellidae Sabellidae 0 1 7 8 Sabellidae ANNELIDA POLYCHAETA SABELLIDA Sabellidae Sabella Sabellatube 0 1 1 2 Sabellidae ANNELIDA POLYCHAETA SABELLIDA Sabellidae Sabellidae Sabellidae (tube) 8 0 0 8 Sabellidae

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Example of truncation. Bryozoa were truncated to different levels for data sets including data from all years and data set limited to 2014-2015.

Assigned Taxon - All Assigned Taxon - 14- Level 3 Level 2 Level 1 Recorded Taxon N12 N14 N15 Years 15

BRYOZOA BRYOZOA BRYOZOA Bryozoa (massive/turf)) 110 0 0 Bryozoa Massive/Turf Bryozoa Turf BRYOZOA BRYOZOA BRYOZOA Bryozoaturf 0 7 34 Bryozoa Massive/Turf Bryozoa Turf Reptadeonella Reptadeonella Adeonidae Reptadeonella Reptadeonella violacea 0 0 2 Bryozoa Crust violacea violacea Bryocryptellidae Palmiskenea Palmiskenea skenei Palmiskenea skenei 0 0 2 Bryozoa Massive/Turf Palmiskenea skenei Bugulidae Bugulina Bugulina Bugulina 0 16 0 Bryozoa Massive/Turf Bugulina Bugulidae Bugulina Bugulina Bugulina turbinata 0 2 1 Bryozoa Massive/Turf Bugulina Candidae Scrupocellaria Scrupocellaria Scrupocellaria 0 9 1 Bryozoa Massive/Turf Scrupocellaria Cellariidae Cellaria Cellaria Cellaria 0 28 175 Bryozoa Massive/Turf Cellaria Cellariidae Cellaria Cellaria Cellaria sp. 50 0 0 Bryozoa Massive/Turf Cellaria Celleporidae Cellepora Cellepora pumicosa Cellepora pumicosa 0 0 39 Bryozoa Crust Celleporidae Celleporidae Celleporidae Celleporidae Celleporidae 0 28 130 Bryozoa Crust Celleporidae Omalosecosa Celleporidae Omalosecosa Omalosecosa ramulosa 0 0 13 Bryozoa Massive/Turf Celleporidae ramulosa Omalosecosa Omalosecosa Celleporidae Omalosecosa 0 1 3 Bryozoa Massive/Turf Celleporidae ramulosa ramulosay … … … … … … … … … Schizobrachiella Schizobrachiella Schizobrachiella Schizoporellidae Schizobrachiella 0 0 16 Bryozoa Crust sanguinea sanguineaY sanguinea Smittinoidea Parasmittina Parasmittina trispinosa Parasmittina trispinosa 0 1 68 Bryozoa Crust Smittinoidea Smittinoidea Smittina Smittina landsborovii Smittina landsborovii 0 0 11 Bryozoa Massive/Turf Smittinoidea Smittinoidea Smittinoidea Smittinoidea Smittinoidea 0 0 259 Bryozoa Massive/Turf Smittinoidea Alcyonidium Alcyonidium Alcyonidiidae Alcyonidium Alcyonidium diaphanum 0 27 17 Bryozoa Massive/Turf diaphanum diaphanum Vesiculariidae Vesicularia Vesicularia spinosa Vesicularia spinosa 0 2 0 Bryozoa Massive/Turf Vesicularia spinosa Crisiidae Crisiidae Crisiidae Crisiidae 0 29 15 Bryozoa Massive/Turf Crisiidae Lichenoporidae Lichenoporidae Lichenoporidae Lichenoporidae 0 1 0 Bryozoa Crust Lichenoporidae .

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The 2014-2015 combined dataset allowed for less extensive truncation, thereby retaining more taxonomic detail. In most cases, taxa were truncated to the highest common taxonomic level. Where there was a mixture of taxonomic levels with several observations given both at a general group level (e.g. unidentified Bryozoa turf) and for individual taxa within that group, the more detailed taxonomic groups were kept separate in the dataset, but observations from the lower taxonomic level were also aggregated into the higher category entries in the final dataset. The aggregation was carried out to avoid artificially inflating variability in taxonomic composition, whilst simultaneously maintaining as much taxonomic detail as possible. Yellow branching sponges, recorded in the various datasets as axinellidae, Stelligera stuposa and Raspailia spp., were combined together as Axinella/Raspailia/Stelligera due to their similarity and potential for misidentification. Whilst it is possible that all three taxa were present in the images, it was observed that branching sponges at the same station in different years were identified as Axinellidae in one year and Raspailia another year, leading to the decision to combine the taxa into a morphospecies.

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Annex 3. Rationale for using counts of individuals and taxa from still images in condition monitoring. The spatial sampling design for still images is units collected in linear replicates, in the form of camera tows, at N stations. The individual tows are assumed to be a representative and random sample of each habitat type present at the site. Count data of individuals of given taxa and the total number of taxa are recorded for each image. Examples of taxa where individuals are enumerated include species FOCI (such as the Pink Sea-Fan, Eunicella verrucosa, at The Manacles MCZ) and specific taxa selected as indicators of habitat condition (e.g., such as sponge morphs).

For specific taxa, frequency distributions are unlikely to be normal, as presence and abundance are habitat dependent for most taxa. The habitat dependent distribution dictates that the probability of presence (or high or low abundance), is not equal across, or where habitat changes during tow, within tows. Therefore, a more equal sample can be obtained by sub-dividing the still images within a station, as sub- stations within a habitat.

Observations along camera transects are not independent of each other. In particular, stills acquired along a given transect are likely to be more similar than stills acquired from different camera transects. There might also be spatial correlation within a station/transect – for example, stills acquired at adjacent areas of seabed might be more similar than those acquired further apart.

In order that the overall mean is not biased by the number of stills per station, we calculate the mean of counts in individual still images within a habitat type within a transect to arrive at a representative station mean. We then use these station means, as a stratified mean to estimate our overall mean for each stratum (habitat, location, time).

Formally, we define this stratified estimator as:

S yst =  y j j=1

th Where y j is the mean of the replicates for the j station and the summation is over the S stations within the stratum. We can calculate, for example, 95% confidence intervals for yst from the fact that

S 2 var(yst ) =  j / n j j=1

2 th Where  j is the variance of observations at the j station and nj is the number of replicates at the jth station.

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Using the stratified mean value per transect avoids the need for equal numbers of stills from each station.

In view of continued time series monitoring (i.e. regular repeat surveys), the use of the stratified estimator does not require the same locations to be repeat sampled where the assumptions of the analysis are met, i.e. the stations are a representative or comprise a random sample of their stratum (e.g. habitat A in region X at time T). This is desirable where sampling is carried out using a towed camera system, which is unlikely to exactly replicate the previous sampling location and may in some cases (e.g. where tidal flow dictates the direction of tow) sample entirely different areas of seabed. In fact, a fully stratified random design will provide a better estimate over time of the region of interest as a whole as opposed to using a fixed station approach, which assess change only at those ‘sentinel’ stations.

The recommended procedure for the calculation of a stratified mean value is:

1) Define the strata – in this case Broadscale Habitats (or where required, more detailed habitat types, e.g. for species FOCI), and the areas for comparison (e.g., within/outside a management area);

2) Assign representative random sampling locations to the strata;

3) Calculate mean counts for each stratum at each station (post-image- analysis stratification where required); and

4) Calculate the mean per stratum.

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Annex 4. Marine litter Categories and sub-categories of litter items for Sea-Floor from the OSPAR/ICES/IBTS for North East Atlantic and Baltic. Guidasence on Monitoring of Marine Litter in European Seas, a guidance document within the Common Implementation Strategy for the Marine Strategy Framework Directive, MSFD Technical Subgroup on Marine Litter, 2013.

A: Plastic B: Metals C: Rubber D: Glass/ E: Natural F: Miscellaneous Ceramics products/ Clothes

A1. Bottle B1. Cans C1. Boots D1. Jar E1. Clothing/ F1. Wood (food) rags (processed)

A2. Sheet B2. Cans C2. D2. Bottle E2. Shoes F2. Rope (beverage) Balloons

A3. Bag B3. Fishing C3. Bobbins D3. Piece E3. Other F3. Paper/ related (fishing) cardboard

A4. Caps/ lids B4. Drums C4. Tyre D4. Other F4. Pallets

A5. Fishing line B5. C5. Other F5. Other (monofilament) Appliances

A6. Fishing line B6. Car (entangled) parts

A7. Synthetic B7. Cables Related size categories rope A: ≤ 5*5 cm = 25 cm2 A8. Fishing net B8. Other B: ≤ 10*10 cm = 100 cm2 A9. Cable ties C: ≤ 20*20 cm = 400 cm2 A10. Strapping 2 band D: ≤ 50*50 cm = 2500 cm E: ≤ 100*100 cm = 10000 cm2 A11. Crates and containers F: ≥ 100*100 cm = 10000 cm2

A12. Plastic diapers

A13. Sanitary towels/ tampons

A14. Other

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Annex 5. Non-indigenous species (NIS). Taxa listed as non-indigenous species (present and horizon) which have been selected for assessment of Good Environmental Status in GB waters under MSFD Descriptor 2 (Stebbing et al., 2014).

Species name List Species name List Acartia (Acanthacartia) tonsa Present Alexandrium catenella Horizon Amphibalanus amphitrite Present Amphibalanus reticulatus Horizon Asterocarpa humilis Present Asterias amurensis Horizon Bonnemaisonia hamifera Present Caulerpa racemosa Horizon Caprella mutica Present Caulerpa taxifolia Horizon Crassostrea angulata Present Celtodoryx ciocalyptoides Horizon Crassostrea gigas Present Chama sp. Horizon Crepidula fornicata Present Dendostrea frons Horizon Diadumene lineata Present Gracilaria vermiculophylla Horizon Didemnum vexillum Present Hemigrapsus penicillatus Horizon Dyspanopeus sayi Present Hemigrapsus sanguineus Horizon Ensis directus Present Hemigrapsus takanoi Horizon Eriocheir sinensis Present Megabalanus coccopoma Horizon Ficopomatus enigmaticus Present Megabalanus zebra Horizon Grateloupia doryphora Present Mizuhopecten yessoensis Horizon Grateloupia turuturu Present Mnemiopsis leidyi Horizon Hesperibalanus fallax Present Ocenebra inornata Horizon Heterosigma akashiwo Present Paralithodes camtschaticus Horizon Homarus americanus Present Polysiphonia subtilissima Horizon Rapana venosa Present Pseudochattonella verruculosa Horizon Sargassum muticum Present Rhopilema nomadica Horizon Schizoporella japonica Present Telmatogeton japonicus Horizon Spartina townsendii var. anglica Present Styela clava Present Undaria pinnatifida Present Urosalpinx cinerea Present Watersipora subatra Present

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Additional taxa listed as non-indigenous species in the JNCC ‘Non-native marine species in British waters: a review and directory’ report by Eno et al. (1997) which have not been selected for assessment of Good Environmental Status in GB waters under MSFD Descriptor 2.

Species name (1997) Updated name (2017) Thalassiosira punctigera Thalassiosira tealata Coscinodiscus wailesii Odontella sinensis Pleurosigma simonsenii Grateloupia doryphora Grateloupia filicina var. luxurians Grateloupia subpectinata Pikea californica Agardhiella subulata Solieria chordalis Antithamnionella spirographidis Antithamnionella ternifolia Polysiphonia harveyi Neosiphonia harveyi Colpomenia peregrine Codium fragile subsp. atlanticum Codium fragile subsp. tomentosoides Codium fragile subsp. atlanticum Gonionemus vertens Clavopsella navis Pachycordyle navis Anguillicoloides crassus Goniadella gracilis Marenzelleria viridis Clymenella torquata Hydroides dianthus Hydroides ezoensis Janua brasiliensis Pileolaria berkeleyana Ammothea hilgendorfi Elminius modestus Austrominius modestus Eusarsiella zostericola Corophium sextonae Rhithropanopeus harrissii Potamopyrgus antipodarum Tiostrea lutaria Tiostrea chilensis Mercenaria mercenaria Petricola pholadiformis Mya arenaria

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