O'Sullivan, D., Leahy, Y., Guinan, J. & Shipboard Scientific Party (2017). Sensitive Ecosystem Assessment and ROV Exploration of Reef Survey Report 2017. Cruise Report prepared by INFOMAR and the Marine Institute, Galway, Ireland to the Department of Agriculture, Food and the Marine, the European Maritime and Fisheries Fund and the National Parks and Wildlife Service. A requirement exists to quantify the abundance and distribution of offshore biogenic and geogenic reef habitats in Irish waters to fulfil Ireland?s legal mandate and to generate baseline data from which appropriate monitoring systems can be established. To address this an extensive offshore reef survey of Ireland?s Northwest Continental margin was commissioned by the National Parks and Wildlife Service (NPWS), funded by the European Maritime and Fisheries Fund (EMFF), and coordinated and led by INFOMAR (Integrated Mapping for the Sustainable Development of Ireland?s Marine Resources) and Ireland?s Marine Institute. The objectives of the survey were to implement the EMFF?s Marine Biodiversity Scheme - Natura Fisheries by mapping offshore reef habitats with a view to protecting them from deterioration due to fishing pressures. The reef project aligns with sub-article 6.2 of the Habitats Directive (EC 92/43/EEC) which requires member states to take measures to avoid deterioration of protected habitats. A survey, Sensitive Ecosystem Assessment and ROV Exploration of Reef (SeaRover), took place in July 2017 aboard the ILV Granuaile equipped with the Marine Institute?s remotely operated vehicle (ROV) Holland 1 and a multidisciplinary team of scientists to observe seabed features and biological associations along the northwest continental shelf. The Holland 1 employs high-definition (HD) camera, various composite video feeds and a robotic arm to facilitate sample collection. The primary scientific objective was to map the distribution and abundance of geogenic and biogenic reef habitat along the northwest shelf edge of Ireland?s continental slope with HD video. Secondary objectives included the collection of biological samples for genetic and population analysis and the collection of sediment cores for ground-truthing seabed mapping data and analysis of micro-plastics within deep-water sediment. None