A study on the Construction and Ecological succession of two Small Artificial Reefs on the Swedish West Coast

Sammanfattning: Artificial reefs are being built in most parts of the world for a wide variety of purposes. Divingtourism is a common motivator for the construction of many reefs, particularly in the tropics,although the most widely used purpose is to improve or reconstruct hard bottom habitats andincrease the yield from fisheries. There are two main reasons for why aquatic life is attracted toartificial reefs. They provide excellent protection by often being hollow or filled with crevicesand cavities and increasing opportunities for improved foraging through accumulating biomassand extending the foraging range of an organism by acting like stepping stones. Sweden is acoastal country with few artificial reefs. In this study, two reefs were constructed in the sea offthe coast of Halmstad, Sweden to test small scale artificial reef production, marine organismcolonisation of the reefs during the first year, and to increase the local marine life diversity.Many marine organisms that would not normally occur in the sites where the reefs wereconstructed were observed, such as Symphodus melops and Anguilla anguilla. The reefs alsoprovided a new “clean slate” substrate for the settling of sessile organisms such as Urticina felinaor partially sessile organisms (i.e. during a certain stage of their life-cycle) such as some speciesof Cnidaria polyps. The tested method to construct these reefs was relatively cost effective for itspurpose. However a few minor but vital improvements, such as better binding materials, areneeded. Local marine life in the area has become more diverse during the experiment and thatalone is enough reason to motivate construction of similar reefs along the Swedish coast.