A geotechnical survey campaign was undertaken within the vicinity of the Westermost Rough Offshore Wind Farm. This was supported by a preliminary review of acoustic data and assessment for the presence of Annex I reefs to minimise the risk of potential damage to protected features. Following the review of existing data, a drop down video survey protocol was developed (EMU, 2011) and approved by the Marine Management Organisation (MMO). Part of this protocol identified that a number of proposed geotechnical sampling sites were likely to be in the vicinity of potential Annex I reefs and therefore warranted field ground-truthing by means of drop down video to verify the presence and status of these features. The video ground-truthing survey has now been completed. Drawing upon the findings of this survey, the 2012 EMU report present within this series provides an update of the assessment of the potential Annex I reefs present at the proposed geotechnical sample locations and fulfils condition 3.1.1 of the Marine Licence (Licence L/2011/001075). The aim of the 2013 Fugro EMU document also present within this series was to satisfy Marine Licence condition 31.22 and to address the responses from the MMO regarding the Annex I reef features (letter ref: REN024, dated 12th April 2013, and 21st June 2013). The objectives were to assess the impacts (direct and indirect) of the construction activities on the potential Annex I features. The objectives of this report were to: 1. Assess the direct impact (loss of habitat) of each of the construction activities; 2. Assess the associated indirect impacts (increase in sediment smothering, and suspended sediment concentrations. 3. Assess the cumulative impacts of all construction activities.

Classification of the Atlantic Ocean seabed into broad-scale benthic habitats employing a hierarchical top-down clustering approach aimed at informing Marine Spatial Planning. This work was performed at the University of Plymouth in 2021 with data provided by a wide group of partners representing the nations surrounding the Atlantic Ocean. It classifies continuous environmental data into discrete classes that can be compared to observed biogeographical patterns at various scales. It has 3 levels of classification. For ease of use, a layer is provided for each level. Level 1 has 4 classes. Level 2 has 15 classes nested within level 1. Layers indices are 2 digits (1[level1 class index]1[level 2 class index]). Level 3 has 157 classes nested within level 2 and class names have 4 digits (1digit[level1 class index]1[level 2 class index]2[level 3 class index]). Note that the classification was performed for the whole world and thus it has more classes than in the presented layer.

Classification of the seabed in the Atlantic Ocean into broad-scale benthic habitats employing a non-hierarchical top-down clustering approach aimed at informing Marine Spatial Planning. This work was performed at the University of Plymouth in 2021 with data provided by a wide group of partners representing the nations surrounding the Atlantic Ocean. It classifies continuous environmental data into discrete classes that can be compared to observed biogeographical patterns at various scales. It has 3 levels of classification. The numbers in the raster layer correspond to individual classes. Description of these classes is given in McQuaid, K.A. et al. (2023).

For the mapping of the canyon features a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the MARCONI, CONTOURIBER and MOWER projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m

This geographic dataset contains geospatial information related to events (sightings and interactions) with orcas along the Iberian coast, reported through the portal https://geoanavnet.hidrografico.pt. For more information, please consult https://arcg.is/1POGT9. This dataset is part of the High-Value Datasets (HVD) identified in accordance with Implementing Regulation No. 2023/138 of Directive (EU) 2019/1024, concerning open data and the re-use of public sector information.

Geological features of seabed habitats extracted from an extant layer of the official cartography of the MPA

The Institute of Estuarine and Coastal Studies (IECS) was commissioned by Forewind Ltd to carry out a Phase 1 biotope survey of the intertidal zone located between the towns of Redcar and Marske-by-the-Sea, Tees estuary, Teesside. This area has been identified as a preferred landfall location for export cables, with the ultimate aim of connecting offshore wind farms off the Teesside coastline to the National Grid. The intertidal survey was completed as part of the development of the Environmental Impact Assessment (EIA) required from Forewind Ltd to continue with the proposal to use this area as a landfall site.

Lewis Wave Power Ltd. (LWP) (a wholly owned subsidiary of Aquamarine Power Ltd.) was seeking to develop a wave energy demonstration array off the west coast of the Isle of Lewis. As a first stage of the Environmental Impact Assessment (EIA) for the project, LWP commissioned Royal Haskoning Ltd. to produce an Environmental Scoping Report (Lewis Wave Power Ltd., 2011) to facilitate the identification and assessment of the potential environmental impacts associated with the project. The survey reported on here formed this field-based benthic component. Its purpose was to provide site-specific benthic data to inform an assessment of impact of the proposed development. The key objectives were to: Determine the distribution and abundance of marine habitats and communities within the study areas; Determine the substrate type at all locations sampled and Identify habitats or species of conservation importance.

This dataset assembles historical information existing in public and private documentary archives. Taken together, these data contribute to the building of a knowledge base of the historical presence, extent and biogenic formations of European flat oyster ecosystems prior to and during the intensification of bottom fishing activities. To identify and recover such information requires significant resources and expertise. The establishment of a Historical Ecology Working Group under the umbrella of the Native Oyster Restoration Alliance in early 2020 presented a unique opportunity to coalesce interdisciplinary expertise and resources from multiple European countries to collate and interrogate historical data sources. To date, this is the only known dataset that evidences the past distribution, extent and characteristics of this seabed ecosystem across its full biogeographic range. The described datasets present qualitative and quantitative extracts from written records published between 1524-2022, which show: (1) estimated locations of past oyster fisheries and/or reef habitat across its full biogeographical range, with associated levels of confidence; (2) recorded extent of past reef habitats, and; (3) species associated with these habitats. This comprehensive historical analysis demonstrates that oyster reefs were once a dominant three-dimensional feature along much of the European coastline and some shallow shelf seas.

For the mapping of the canyon features a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m Publication: Ercilla, G., Juan, C., Hernández-Molina, F. J., Bruno, M., Estrada, F., Alonso, B., ... & Ammar, A. (2016). Significance of bottom currents in deep-sea morphodynamics: an example from the Alboran Sea. Marine Geology, 378, 157-170.