Benthic and Fish Interactions With Pipeline Protective Structures in the North Sea

An increasing number of pipelines and associated protective materials in the North Sea are reaching end their operational life require decommissioning. Identifying optimal decommissioning option from an environmental perspective requires understanding ecological interactions; currently there is little knowledge as to species associations with materials. This study utilises industry ROV footage quantify these interactions. A total 58 taxa were identified, including 41 benthic 17 fish taxa. Taxa grouped into seven groups for analysis four epifauna: grazers, suspension/filter feeders, decapods, colonial/encrusting Fish organised three groups: pollock, other fish, gadoids. Using zero-inflated generalised linear mixed models, we show that abundances epifauna vary between types structure (e.g., concrete mattresses, rock dump), depth, levels fishing effort proximity oil gas platforms. Six exhibited higher on mattresses than bare epifaunal decapods showing highest difference at 3.04 (1.83, 4.84, 95% CrI) times compared pipelines. abundance within 500 m fisheries exclusion zone around platforms, outside zone, gadoids 1.83 (1.09, 2.89, inside zones. Five decreased increase effort, biggest effect observed grazers which by 28% (14 – 40, per 50 h fishing. We operating artificial reefs, our results suggest removal infrastructure could result loss habitat species.