This survey was conducted on board the RV Celtic Explorer in 2012 by the Marine Institute (MI) as part of the annual groundfish survey to determine the distribution and abundance of commercial fish around Ireland. The Irish Groundfish Survey (IGFS) forms part of the International Bottom Trawl Survey (IBTS) programme, an international survey effort coordinated by the International Council of the Exploration of the Sea (ICES). Each year the survey, taking place in Autumn/Winter, collects demersal trawl and ancillary data in Irish waters to produce relative abundance indices for fisheries management. In particular the survey provides an index of the share of young fish in the stock, which in turn gives an indication of its spawning success. The IGFS contributes to Ireland’s international obligation to supply scientific data that support the implementation of the Common Fisheries Policy (CFP). In Irish waters, France and Ireland survey the Celtic Sea area, Ireland surveys the shelf West of Ireland, Ireland and the UK Scotland cover the north coast of Ireland and the UK and Northern Ireland survey the Irish Sea. This survey is a series of demersal sampling trawls at pre-defineds stations. The 2012 survey took place over 2 legs. This survey, Leg 1, focused on the northerly ICES Area and took place in late September and early October, while Leg 2 in the western and southern areas was carried out during November/December. In order to make data as comparable as possible, each survey operates under a set of agreed standard protocols. Each tow is 30min long and takes place during daylight hours at 3.5-4 knots. Net geometry and ground contact is monitored and logged. All fish and commercial shellfish are sorted to species level prior to taking lengths and other biological measurements such as age, sex and maturity. a. To determine the relative abundance and distribution of pre-recruits for the main commercial species and provide recruitment indices b. To monitor changes in the stocks of commercial fish species independently of commercial fisheries data; c. To monitor the distribution and relative abundance of all fish species and selected invertebrates; d. To collect data for the determination of biological parameters for selected species. e. To collect hydrographical information on the water column(Conductivity, Temperature and Depth (CTD) sampling)