Search

As decommissioning of oil and gas (O&G) installations intensifies in the North Sea, and worldwide, debate rages regarding the fate of these novel habitats and their associated biota—a debate that has important implications for future decommissioning of offshore wind farms (OWFs). Calls to relax complete removal requirements in some circumstances and allow part of an O&G installation to be left in the marine environment are increasing. Yet knowledge regarding the biological communities that develop on these structures and their ecological role in the North Sea is currently insufficient to inform such decommissioning decisions. To focus debate regarding decommissioning policy and guide ecological research, we review environmental policy objectives in the region, summarize existing knowledge regarding ecological aspects of decommissioning for both O&G and OWF installations, and identify approaches to address knowledge gaps through science–industry collaboration. We find that in some cases complete removal will conflict with other policies regarding protection and restoration of reefs, as well as the conservation of species within the region. Key ecological considerations that are rarely considered during decommissioning decisions are: (i) provision of reef habitat, (ii) productivity of offshore ecosystems, (iii) enhancement of biodiversity, (iv) protection of the seabed from trawling, and (v) enhancement of connectivity. Knowledge gaps within these areas will best be addressed using industry infrastructure and vessels for scientific investigations, re-analysis of historical data held by industry, scientific training of industry personnel, joint research funding opportunities, and trial decommissioning projects.

The aim of this document is to provide a resource to researchers in marine conservation by giving summaries of the international instruments that may have implications for marine conservation in the MarCons region. These instruments include international agreements and conventions, regional agreements and intergovernmental sectoral agreements, and European directives and policies, which directly or indirectly determine marine conservation policies and management. This provides the basis for an inherently interdisciplinary cross-sectoral approach to conservation policy analysis.

Offshore wind farms are expected to contribute significantly to the Belgian 2020 tar- gets for renewable energy. As of 2016, an installed capacity of 870 Megawatt (MW), consisting of 232 offshore wind turbines, is operational in the Belgian part of the North Sea. In 2017 and 2018, an additional capa- city of respectively 275 and 320 MW will be added (fig. 1), with three other projects sche- duled for the next few years after that. With 238 km2 reserved for offshore wind farms in Belgium and 344 km2 in the adjacent Dutch Borssele, cumulative ecological im- pacts may however be expected. These im- pacts both positive and negative, triggered an environmental monitoring programme focusing on various aspects of the marine ecosystem components, but also on the human appreciation of offshore wind farms. This chapter provides an overview of the offshore renewable energy development in the Belgian part of the North Sea.

Piling driving sound is known to impact harbour porpoise (Phocoena phocoena) distribution, but to date detailed knowledge on the combined spatial and temporal components of this impact over longer time periods remains lacking. From May to September 2016, pile driving was taking place at the Nobelwind wind farm located on the Bligh Bank in Belgium. In this period, porpoise activity was recorded using passive acoustic monitoring (PAM) using Continuous Porpoise Detectors (C-PoDs), at various distances from the construction site (1 – > 55 km). In this study, we compared porpoise detections before, during and after pile driving. During piling, porpoise detections decreased at stations located up to 20 km from the location of the piling event. At larger distances (20-55 km), porpoise detections either remained the same or increased slightly during piling events, which may be due to displaced porpoises entering the area. Underwater sound levels were extrapolated for the different locations. Pile driving sound levels at the furthest distance where reductions in porpoise detections were observed were ~159 dB re 1μPa (Lsub>z-p), which is close to the threshold level for major disturbance for harbour porpoise proposed in literature.

The harbour porpoise (Phocoena phocoena) is the most abundant cetacean in the Belgian part of the North Sea. We developed a mooring system for static passive acoustic monitoring (PAM) of this species using c-PoDs at locations of opportunity. Data of moorings between 2010 and 2015 at two locations were analysed. They revealed a significant seasonal trend in detections, assessed by month, with peaks in late winter - early spring and late summer, consistent with the results of aerial surveys and with strandings data. At one location there were significant differences in detections between years, with higher detection rates in every year between 2011 and 2014, and the highest detection rates in 2013 and 2014. The experiences gained are used to design a subsequent study strategy to monitor harbour porpoise presence in Belgian waters, including possible effects on their presence due to the construction of offshore windfarms.

There is concern about possible effects on the marine ecosystem of high levels of underwater noise generated during pile driving for the construction of offshore wind farms. As a result, various national governments in Europe have identified limits of underwater sound levels, as such imposing in many cases the use of noise mitigation measures. In this paper we compare the regulations with regard to impulsive underwater noise in the Belgian wind farm zone with those in the Dutch wind energy zone of Borssele. These (planned and existing) wind farms are situated at opposite sides of the maritime border between both countries. These regulations are quite different and at times even contradictory and developers could benefit from an alignment of regulatory practices on a regional basis. Measurements of piling noise from constructed wind farms are used to extrapolate the anticipated noise levels of the next two wind farms to be constructed, and these are evaluated in relation to the new regulations on underwater sound. Wind farm developers are already developing strategies for costeffective piling noise reduction but uncertainty remains with regards to both the level of underwater noise produced during piling as well as with the effectiveness of the noise mitigation measures being applied. Our results indicate that a combination of noise mitigation measures may need to be used to comply with the new regulations.

Offshore wind farms are expected to contribute significantly to the Belgian 2020 targets for renewable energy. Today, 182 turbines are operational in the Belgian part of the North Sea. In the next few years, an additional 234-342 turbines may be installed. With 238 km² reserved for offshore wind farms in Belgium and 344 km² in the adjacent Dutch Borssele, cumulative ecological impacts may however be expected. These impacts both positive and negative, triggered an environmental monitoring programme focusing on various aspects of the marine ecosystem components, but also on the human appreciation of offshore wind farms. This report provides an overview of the offshore renewable energy development in the Belgian part of the North Sea.

As a response to increasing human pressures on marine ecosystems, the legislation aimed at improving the conservation and management of marine coastal areas in European and Contiguous Seas (ECS) underwent crucial advances. ECS, however, still remain largely affected by increasing threats leading to biodiversity loss. Here, by using emblematic case studies and expert knowledge, we review current conservation tools, comparing their application in different areas to assess their effectiveness, potential for synergies, and contradictions. Despite regional differences in their application, the existing legislative frameworks have the potential to regulate human activities and to protect marine biodiversity. However, four challenges remain to be addressed to fully achieve environmental policy goals: (1) Lack of shared vision representing a limitation in transboundary collaboration. Although all EU countries are committed to fulfil EU Directives and other binding international legislative acts, a remarkable heterogeneity exists among countries in the compliance with the common legislation on conservation and in their degree of implementation. (2) Lack of systematic procedures for the selection of protected marine sites. Regional and national approaches in designating Natura 2000 sites and nationally designated marine protected areas (MPAs) reflect varying conservation targets and importance of conservation issues in political agendas. (3) Lack of coherent ecological networks. Natura 2000 sites and other MPAs are still far from reaching the status of effective networks in all considered case studies. (4) Hotspot of conflicts with private economic interests prevailing over conservation aims. Recommendations are given to overcome the fragmented approach still characterizing the conservation and management of coastal marine environments. Holistic, integrated, ecosystem-based, cross-cutting approaches can avoid conflicts among institutions so as to provide effective and timely solutions to current and future challenges concerning the conservation and management of marine ecosystems and associated goods and services. © 2018 Fraschetti,.