Artificial reefs have been deployed purposely worldwide to influence physical and biological processes around coastlines and in inshore waters; often to augment recreational diving and fishing, support environmental mitigation and habitat restoration and, more recently, for scientific research. The aims of this project were to develop standardised methods and protocols for use in artificial reef studies and to establish whether there were differences in the productivity and biotic interactions between artificial and nearby natural rocky reefs in Loch Linnhe, west coast of Scotland.
A comparative study was carried out to evaluate methods used in the assessment of subtidal epibiotic assemblage structure followed by a detailed study to compare epibiotic recruitment to artificial and natural reefs using PVC plastic recruitment panels. Predator exclusion cages were used to assess the effects of predation on epifaunal recruitment at different locations. Epifaunal biomass on concrete reef blocks and infaunal biomass in soft sediments surrounding the artificial reef complex was determined and an estimate made of relative productivity between the Loch Linnhe artificial reef modules and their receiving environment. Finally, the trophic dynamics of artificial and natural reefs were investigated through the use of stable isotope ratios.
These studies showed that post-settlement processes appear to be controlling differences in epifaunal recruitment to artificial and natural reefs in Loch Linnhe. Vertically orientated PVC recruitment panels, combined with galvanised wire mesh predator exclusion cages, are recommended for use in comparative recruitment studies of subtidal artificial and natural reefs. It was also concluded that the Loch Linnhe artificial reef complex has increased the productivity to the local area and that the construction design of these artificial reefs would be a suitable option, with respect to the development of biological communities, for future artificial structures such as breakwaters