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Social network analysis as a tool for marine spatial planning: Impacts of decommissioning on connectivity in the North Sea

Journal of Applied Ecology Volume 57, Issue 3


Connectivity of marine populations and ecosystems is crucial to maintaining and enhancing their structure, distribution, persistence, resilience and productivity. Artificial hard substrate, such as that associated with oil and gas platforms, provides settlement opportunities for species adapted to hard substrates in areas of soft sediment. The contribution of artificial hard substrate and the consequences of its removal (e.g. through decommissioning) to marine connectivity is not clear, yet such information is vital to inform marine spatial planning and future policy decisions on the use and protection of marine resources.

This study demonstrates the application of a social network analysis approach to quantify and describe the ecological connectivity, informed by particle tracking model outputs, of hard substrate marine communities in the North Sea. Through comparison of networks with and without artificial hard substrate, and based on hypothetical decommissioning scenarios, this study provides insight into the contribution of artificial hard substrate, and the consequence of decommissioning, to the structure and function of marine community connectivity.

This study highlights that artificial hard substrate, despite providing only a small proportion of the total area of hard substrate, increases the geographic extent and connectivity of the hard substrate network, bridging gaps, thereby providing ‘stepping stones’ between otherwise disconnected areas of natural hard substrate. Compared to the baseline scenario, a decommissioning scenario with full removal of oil and gas platforms results in a nearly 60% reduction in connectivity. Such reduction in connectivity may have negative implications for species’ distribution, gene flow and resilience following disturbance or exploitation of marine hard substrate communities.

Synthesis and applications. Social network analysis can provide valuable insight into connectivity between marine communities and enable the evaluation of impacts associated with changes to the marine environment. Providing standardized, transparent and robust outputs, such a tool is useful to facilitate understanding across different disciplines, including marine science, marine spatial planning and marine policy. Social network analysis therefore has great potential to address current knowledge gaps with respect to marine connectivity and crucially facilitate assessment of the impacts of changes in offshore substrate as part of the marine spatial planning process, thereby informing policy and marine management decisions.

Application in MSP:
Type of Issue:
Type of practice:
Stage of MSP cycle:
Cross-border / trans-national aspect:
Key words:

Questions this practice may help answer:

  • What could be the consequences of decommissioning energy infrastructures on marine connectivity?
  • How can marine connectivity be evaluated?
  • What are the contributions of social network analysis in the context of Maritime Spatial Planning?

Implementation Context:

Around 500 energy-related structures are planned to be decommissioned in the next 30 years; consideration of the consequences of such removals is crutial, especially in relation to implementing Maritime Spatial Planning in the North Sea.

Aspects / Objectives:

The aim of this study is to evaluate the application of a Social Network Analysis (SNA) approach by describing the connectivity of a marine community, comprising seven species with pelagic larval and benthic adult stages, exhibiting a preference for hard substrate habitat.


By adjusting the network to reflect a reduction in hard substrate associated with the removal of oil and gas structures, the impact of different decommissioning scenarios is investigated.

Main Outputs / Results:

The study evaluates the contribution of artificial hard substrates to the marine hard substrate network in the North Sea and the role of artificial hard substrate (in particular with oil and gas platforms) in the connectivity of otherwise isolated areas of natural hard substrate. The merit of applying social network analysis to the assessment of ecological connectivity in a changing environment, and crucially to inform marine spatial planning into the future, is discussed.


This practice can be referred to during the process of decommissioning any oil and gas platforms.

Responsible Entity:

Weymouth Laboratory, Centre for Environment, Fisheries & Aquaculture Science (CEFAS), Weymouth, UK.

Costs / Funding Source:

This work was supported by the INSITE Programme [Foundation Phase, 2016–2017], forming part of the NSITE EcoConnect (Cefas project C6498).

Contact person:

Hannah Tidbury: