Half of these reefs may not recover. Artificial reefs are used to replenish the lost marine life and to create areas for people to fish and dive that will not damage the natural coral reefs. Artificial reefs have many advantages and disadvantages, if done properly the advantages outweigh. Artificial Reefs can provide shelter, calm waters, influence water currents for the benefit of fish, attract smaller organisms that are vital sources of food, serve as visual reference points for fish that forage away, and are used to enhance existing rough bottom habitat. If poorly designed and mounted artificial reefs can damage sedentary organisms of nearby natural reef sites and play havoc with the nets of commercial fisherman s bottom trawl.
Buoys usually mark reefs.
Inadequate buoys, buoy chains, and lost buoys are difficult to find and increase the amount of materials dumped into the sea. Artificial reefs often collect schools of fish, this attracts fishermen and may be a contributing factor to overfishing. In the 1800 s, the Japanese made the first artificial reefs out of bamboo sticks. Since the 1950 s, many materials are used in attempts to make artificial reefs. Because these reefs last as long as the materials, there are usually made out of steel or concrete.