Acoustic mapping of the Seabed of the Menai Strait. South West Menai.

The section of the Menai Straits that were surveyed were divided into three parts. The hardness/roughness isopleths were combined using CAMRIS GIS to produce a composite map showing 7 types of group (very hard/very rough; hard/rough; moderately hard/moderately rough; moderately soft/moderately smooth; soft/moderately rough; soft/smooth; very soft/very smooth). A map for the whole of the survey area was followed by a map showing the biotope types as observed using the remote video, which are as follows (SA = superabundant; A = abundant; C = common; O = occasional) Sand/shell: Medium fine sand with shell: very silty. Coarse sand/silt: Coarse sand: very silty. Gravel: Bar Silty cobble: Silt accretion (A); Cerianthus (O-C); Urticina (O-C). Silty cobble/rich: Silt accretion (A); Sponges (Haliclona, Halichondria) (C); hydroids (C); Urticina (O-C). Boulder/cobble sponge:Similar to above, but with sponges C-A. Cobble/bounder Faunal turf: Hydroids (C); Tubularia (O); Alcyonium(O); Flustra(O). Cobble hydroid turf: Short turf of hydroids (C-A). Cobble Pomatoceros: Pomatoceros and barnacles (A). Bedrock/boulder silt sponge: Similar to boulder/cobble sponge above, but on bedrock/boulder. Boulder Laminaria: Small Laminaria hyperboraea (C); red algal turf (C). Bedrock sponge/Flustra: Bedrock with encrusting sponges (C-A) and Flustra (O-C). Bedrock Mytilus. Small Mytilus (A-SA); Asteria(C-SA); encrusting corralines (O). Bedrock and Faunal turf: Hydroids (C); Tubularia(O); Alcyonium(O); encrusting and branching sponges(O-C). The maps were subsequently transposed into EUNIS in 2006 using expert judgement.