The survey area is the eastern shore of Liverpool Bay, and consists of an almost unbroken expanse of sandy beaches. The area is bounded to the north by Morecambe Bay and to the south by the Mersey estuary, and is split into two by the broad inlet of the Ribble estuary. There are no outcrops of bedrock in the survey area, which consists entirely of glacial and alluvial sediments, fine sand predominating in most areas, but also including isolated patches of boulders and cobbles. The Fylde coast, to the north of the Ribble, is heavily used for recreational purposes, whilst the Ribble estuary and Merseyside foreshore to the south experience less disturbance and are protected by an unbroken series of sites of nature conservation importance with statutory designations. Fifteen sites were surveyed in Spetember 1990, chiefly sampling littoral sediments, but also including natural and artificial hard substrata where these were present. The open Fylde coast supported an impoverished crustacean/polychaete community in mobile fine sand, whilst the open Merseyside coast held a similar community in the upper shore and a much richer community characterised by bivalve molluscs in more stable mid and low shore sand. The outer Ribble and Mersey estuaries held sediment communities typical of such physiographic conditions, consisting of fairly stable fine sand with some silt, and supporting communities characterised by the baltic tellin Macoma balthica, and, in the Ribble, the cockle Cerastoderma edule. The Ribble, and to a lesser extent the Wyre estuary at Fleetwood, also held muddier sediments subject to low and variable salinities, and these contained a community characterised by the polychaete worm Hediste diversicolor and the bivalve mollusc Scrobicularia plana. Natural hard substrata were only found on the Fylde coast and in the Ribble estuary, where boulder and cobble scars were dominated and stabilised by mussels (Mytilus edulis), with abundant barnacles (Semibalanus balanoides) also characteristic. A similar, though impoverished community was found on consolidated clay and boulder exposures near Cleveleys. Beware! the infauna has been entered in the epifauna window Artificial substrata such as pier pilings, groynes and concrete structures were present at a small number of sites and were also dominated by M.edulis, but had a reduced diversity combined with a high biomass. Habitat diversity in the survey area is very limited, with the result that community and species diversity is also reduced compared with most other littoral areas of the same size. The nature conservation importance of the whole area, the communities and the species recorded have been provisionally assessed. One community was considered to be of regional importance, and a further five were considered to be of local importance. No species found during the survey were considered to be of particular conservation importance, all being widespread in similar physiographic conditions in the region.