Abstract
This report details the results from the visual inspection of marine growth on structures within the Hywind Scotland Pilot Park, located east of Peterhead Scotland.
The survey was performed using a Work Class Remotely Operated Vehicle (WROV) with a mounted High Definition (HD) video camera, deployed from the survey vessel M/V Stril Explorer.
A total of 41 structures, as well as their associated subcomponents, were inspected during the survey, including Turbines (Substructures), Mooring Lines, Suction Anchors and Infield Cables. Data from several of the subcomponents have been pooled to facilitate comparison.
All five turbines showed, generally, a distinct trend in zonation with Metridium senile and Spirobranchus dominating the bottom to mid-sections of the turbines while kelp and other Phaeophyceae with blue mussel Mytilus dominated top sections of the turbines.
The fauna, dominating the mooring lines, varied with depth and general zonation’s could be distinguished. Ross worm, Sabellaria spinulosa and cnidarian Ectopleura larynx dominated the chains where the chains were close to and in contact with the seabed, Spirobranchus dominated the middle part of the chains and the upper parts of the chains were dominated by Balanoidea, M. senile and E. larynx.
The suction anchors were dominated by hydroids and the tube building worm Spirobranchus.
The infield cables were mainly buried, however, the section of the cables that were exposed before going into burial were dominated by acorn barnacles (Balanoidea).
No confirmed non-native taxa were noted during the survey. Several individuals of lobster Homarus spp. were identified and these could belong to one or both of the species European lobster H. gammarus or the invasive non-native American lobster H. americanus.
Four mobile taxa featured on the Scottish Biodiversity List and as Priority Marine Features were identified in close proximity of the structures; Cod Gadus morhua, Ling Molva molva, sand eel Ammodytes spp. and Whiting Merlangius merlangus.
The habitat “Subtidal Sand and Gravels” featured on the Scottish Biodiversity List and Priority Marine Features was identified in the survey area.
Ross worm, S. spinulosa aggregations were identified growing next to and encrusting the structures situated on the seabed surface. These aggregations could potentially form the habitat, “Sabellaria spinulosa Reefs”, included in OSPAR’s List of Threatened Declining Species and Habitats and within the European Commission Habitats Directive Annex I habitat – 1170 Reefs.
A comparison of the current dataset has been conducted with available data collected during 2018, which showed an increase in both hard and soft marine growth coverage.
The visual inspection survey commenced on the 6th of June 2020 and was completed on the 15th of June 2020.