Epifauna associated with subsea pipelines in the North Sea

An increasing number of pipelines across the UK Continental Shelf are reaching the end of their economic life, resulting in a growing impetus on decommissioning. Implicit to the decommissioning process is the evaluation of the environmental impacts of the different decommissioning options, however little is known regarding the epifauna that interact with these structures. This study utilized industry-collected footage from remotely operated vehicle inspections of pipelines to assess the interactions of benthic epifauna with pipelines, and their associated structures, for the first time. Footage was analysed from across the northern and central North Sea to examine relationships between faunal community compositions and pipelines and their protective coverings. The complex habitat of concrete and Link-lok mattresses had the highest numbers of observable taxa. Differences in community composition were largely due to varying proportions of common epilithic species. There was a weak relationship between pipeline covering type and the species composition of the immediately neighbouring substrate. Depth and latitude were the strongest correlators with the observed community compositions. This study has compiled the first dataset on epifaunal associations with subsea pipelines in the North Sea.