The implications of co-locating marine protected areas around offshore wind farms

Abstract

Offshore wind farm (OWF) construction in the UK is progressing rapidly alongside increasing spatial pressures on marine ecosystems and social and economic activities. A need for increased protection of habitats, species and ecological processes that support environmental and economic benefits is being met by designation of marine protected areas (MPAs). Mitigation and spatial planning solutions are required to enable protection of vital ecological habitats, features and processes and support sustainable economic development. A potential solution is to co-locate OWFs and MPAs. This study uses a multi-disciplinary approach to examine if evidence on the environmental effects of existing OWFs and associated effects on fishing activity (as an existing resource use) benefits MPA goals. Through a systematic review and meta-analyses of existing data, knowledge of OWF effects on species abundance and economic effects on fishing were identified as key evidence gaps. The ecological evidence need was approached through a case study of ecological effects of North Hoyle OWF, North Wales, UK, using existing pre and post-construction monitoring data, as well as primary baited remote underwater video data, collected 5 years later (8 years post-construction). Results suggested habitat and species recovered to a stable state that showed some community differences to pre-construction conditions. The presence of OWF monopiles is likely to have increased existing heterogeneity of substratum and increased opportunities for scavenging species. Species benefitting and disadvantaged by habitat provided within the OWF reflected meta-analyses trends. Extended baseline monitoring to provide confident identification of natural levels of variation in sediment and fauna was lacking. Analysis of fishing activity and landings before and after OWF construction in three UK case study regions approached effects on resource users. Fishing activity in the three case study areas showed broad scale similarity to national trends. Small-scale activity patterns indicated greater reductions in mobile (towed) fishing gear effort near to operating OWFs than in static gear activity (using pots or static nets). Semi-structured interviews conducted with fishermen in each region revealed loss of ground and disruption as negative effects from OWFs, in addition to existing pressures. Benefits including habitat creation and species augmentation, as well as reduction of cumulative lost ground, were identified by fishermen from co-location of MPAs and OWFs. Ecological effects of OWFs suggested benefits from habitat creation, species augmentation and potential for protection of sandbank habitats between monopiles. Mitigation requirements were identified to maximise these potential benefits to an MPA network.