Artificial reefs are human-made structures that are either deliberately or unintentionally submerged underwater, commonly with the result of mimicking some characteristics of a natural reef. Artificial reefs alter local habitat by providing hard substrate and complex vertical relief where typically none previously existed (Bohnsack and Sutherland 1985, Sheehy and Vik 1992, Sheehy and Vik 2010). They may be created from a variety of sources and materials including the intentional sinking of ships and barges, rubble, concrete, rocks, stone, boulders, steel, and metal, etc. (Baine 2001). They may also be created through unintentional means (e.g., shipwrecks that can become historical in nature) and through structures built for other purposes (e.g., decommissioned oil and gas platforms, breakwaters1, jetties, bridges, offshore lighthouses, air force towers, navigational aids, marine data buoys, etc.). These various materials have benefits and drawbacks when used in artificial reef construction.
