Seafloor visual images were acquired during a survey within the Greater Haig Fras Marine Conservation Zone (MCZ), central Celtic Sea, in 2012. This was the first in a series of similar surveys to be conducted in this location. A camera system mounted on the autonomous underwater vehicle (AUV) Autosub6000 was deployed during RRS Discovery cruise 377/8 (D377/8), and images were collected from four 4.7 km transect lines. Images were mosaicked in "tiles" consisting of five consecutive images (each tile representing approximately 7.3 m2 of seabed). Images were orthorectified and scaled to a common altitude per tile. The mosaicked tiles are provided in this collection. The aim of the survey was to undertake high-resolution acoustic seabed mapping and visual imagery in a Marine Protected Area, in order to highlight the capability of AUV technology for offshore seabed mapping and benthic assemblage assessment. The work was initially undertaken as part of a Defra-funded project "Investigating the feasibility of utilizing AUV and Glider technology for mapping and monitoring of the UK MPA network (MB0118)", Case study 2: Shallow-water AUV mapping off SW UK (https://nora.nerc.ac.uk/id/eprint/500733/), and the Natural Environment Research Council (NERC) funded Autonomous Ecological Surveying of the Abyss project (NE/H021787/1), involving scientists from the National Oceanography Centre (NOC), UK.
