The sublittoral hard substrata between Morecambe Bay and Whitehaven was surveyed in 1991 as part of the survey of the north-eastern coast of the Irish Sea for the MNCR. This part of the coast is predominantly sedimentary both in the littoral and sublittoral. The coastline south of Whitehaven to the Isle of Walney is generally linear except for the indentations of the Ravenglass and Duddon estuaries. The Isle of Walney is a barrier island which protects the sheltered waters of the Walney Channel to the east. The extensive sand flats of Morecambe Bay are cut by the Lune Deep which stretches south-westwards from the entrance of the Wyre Channel. Only isolated areas of hard substrata are present in the sublittoral. The most extensive area is the Lune Deep, a glacially formed kettle hole with steep boulder and cobble sides. Smaller areas of rock are present at St Bees Head, where there is outcropping bedrock. More characteristic of the region are the glacial boulder scars found littorally and sublittorally along the open coast and in the Walney Channel. Eighteen sublittoral sites were surveyed on the hard substrata. Seven hard substrata communities were identified from four seperate survey areas: St Bees Head with its exposed sand scoured communities; the rich flora and fauna of an exposed boulder scar at Selker Rocks; the sheltered tide swept scar at Head Scar in the Walney Channel, and the dense hydroid and bryozoan turf in the Lune Deep. Three sediment communities associated with these regions are briefly described. Two hundred and six taxa were identified from the surveys.
