Note these data complement other datasets held by JNCC and the other country agencies that used the same methodology. However, this dataset comprises those data that were paid for by CCW directly. The data contributed to the MNCR programme which was initiated to provide a comprehensive baseline of information on marine habitats and their associated species around the coast of Britain which would aid coastal zone and sea-use management and to contribute to the identification of areas of marine natural heritage importance. The focus of MNCR work was on benthic habitats (often referred to as 'biotopes') in intertidal and inshore (typically within 3nm) subtidal areas. Methods of data capture The majority of data were collected using methods described in the MNCR Rational and Methods report (Hiscock 1996). Broadly, this encompassed surveying a range of sites within a geographical area to sample and describe the variety of habitats present (sampling habitats in different substrata, depths, wave exposures, current regimes, salinity regimes and so on). Each habitat was sampled using semi-quantitative recording techniques (SACFOR abundance scales) for recording epibiota on rocky habitats. Geographical Coverage This dataset relates to Wales. Note however that the dataset "Marine Nature Conservation Review (MNCR) and associated benthic marine data held and managed by JNCC" also includes equivalent and complementary data from Wales. Temporal Coverage The data were collected post 1993. Data Quality The data have been extensively checked during the course of the creation of the various reports produced by the MNCR programme. This included the MNCR Area Summary report series which describes the marine habitats in particular regions around the UK and the creation of the national marine habitat (biotope) classification system. Through this work the vast majority of the anomalies and errors in the data should have been identified but some may still remain.