Habitat point records from 1983 OPRU Bardsey and the Lleyn Peninsula sublittoral survey

The survey was undertaken to describe the range of sublittoral habitats and communities present in nearshore sublittoral areas of Bardsey and the Lleyn Peninsula and to assess their scientific interest and conservation importance. All the survey was carried out using diving, and access to sites was by inflatable boats. At each site surveyed, a botanist and a zoologist recorded the abundance of conspicuous species in the main habitats encountered. A description of the habitats was made and transcribed onto edge-punched cards. Photographs were also taken to illustrate communities and species present. Descriptions are provided of the different sublittoral habitats and communities encountered during the survey. They included distinctive communities on bedrock and boulders from sites exposed to very strong wave action and/or tidal streams to sites sheltered from strong water movement. Distinctive communities on stable rock surfaces were also found on offshore reefs on the north coast of Lleyn in surge gullies and on sandy rock surfaces. Caves at St Tudwal's Island and the headland of Pen-y-Cil were interesting topographical features with communities similar to those of surge gullies. Communities on cobbles occurred at several locations but were particularly well developed south-east of Bardsey and on the south coast of Lleyn near to Aberdaron. Bays at Porth Dinllaen, Aberdaron and south of St Tudwal's Road included several different and predominantly sediment communities. A bed of Zostera marina was present in Porth Dinllaen and maerl was present at St Tudwal's Road. A seperate description was undertaken of algal communities on kelp stipes. There were a wide range of habitats and communities present in the area surveyed reflecting the varied aspects, exposure to water movement, substrata present and topographical features of the coastline. There was a distinctive regional characteristic to some of the communities encountered particularly on the reefs off the north coast of Lleyn. The areas surveyed off the south-east coast of Bardsey were especially rich in species. The conservation importance of the whole area surveyed and of 17 seperate habitats/communities or locations is assessed. 12 algae, Zostera marina and 8 animal species are noted as of particular scientific interest within the area. Most features of conservation interest are considered of regional importance. However, tidal sound communities, communities on tide swept cobbles, the offshore reefs of northern Lleyn and the cave at Pen-y-Cil are considered of higher importance. Any further studies undertaken in the area should include a more detailed investigation of the cave at Pen-y-Cil, of the offshore areas in Hell's Mouth, a study of Caswenan Rock and of the banks east of Bardsey. Records currently considered sensitive have been removed from this dataset.