1986 Oil Pollution Research Unit (OPRU) Harbours, Rias and Estuaries (HRE) Plymouth Harbour and Yealm Estuary survey dataset https://portal.medin.org.uk/portal/start.php?tpc=010_7f5ed3479b13f8a7a399f92f04b6c24c 118 locations in and around Plymouth Harbour and Yealm Estuary. The present survey aimed to collect further information on the marine habitats and communities which had not previously been described or had not been sampled since the early 1900's. The habitats and communities surveyed are compared with those in other marine inlets and with previous marine biological studies in the area. The scientific interest and nature conservation importance of the area has been assessed using standard criteria and the conservation importance of the habitats and communities in the area have been provisionally graded as of Local, Regional, national or International importance. Species of particular scientific interest identified during the survey have been noted and their conservation importance provisionally graded as of Regional, National or International importance. Data on species and biotope recorded and entered onto Marine Recorder. Species data and biotope data mapped as points using MapInfo. 20120117 19910123