reefs at different rates than they would grow in natural reefs.

Considerable research is being done into construction methods and the effects of artificial reefs. Many of the materials used early on are now considered undesirable. A 2001 literature review suggested that about half of the reefs studied met their objectives. Long-term planning and ongoing management were identified as essential factors in success.A more recent analysis of reefs world wide between 1990 and 2020 concludes that artificial reefs can be useful tools for restoring