The long history of artificial reefs has stimulated diversity in their physical properties and deployment for a range of purposes. A systematic literature search yielded 804 scientific publications on artificial reefs. A database of their characteristics was constructed and used to investigate geographical and historical trends. A total of 1074 unique artificial reefs from 71 countries were identified, with 89% located in the northern hemisphere, but equally distributed between eastern and western. Reefs were assigned to one of three categories: (A) unintentional deployment, (B) intentional deployment but unintentional reef, and (C) intentional artificial reef. Category A reefs consisted predominantly of accidental shipwrecks. Category B reefs were primarily coastal defense structures in shallow waters and active oil and gas infrastructures at greater depths. The number of Category C reefs increased after 1965, with most in depths of 10–30 m. Most were constructed from concrete or steel, followed by rock and rubber. Usage of concrete as a material steadily increased, while those of steel and rubber decreased, coinciding with the transition from objects (materials) of opportunity to purpose-built reefs. Most reefs were deployed to enhance faunal communities or fisheries, particularly recreational fishing in North America and Australia. Monitoring was most often performed using underwater visual census but transitioned to more technologically advanced methods, particularly in more affluent countries over recent decades. We present a standardized protocol for describing artificial reefs and urge authors to include all relevant data in their publications to allow future comparisons to enhance our understanding and evaluation of these structures.

The Exmouth Integrated Artificial Reef (King Reef) was deployed in July 2018 and is the first installation in Australia to innovatively combine repurposed oil and gas infrastructure with purpose-built concrete reef modules. The project involved a collaborative approach between industry, government (state and commonwealth), researchers and the community, creating a world-leading engineering solution using science-based habitat enhancement. The project integrated six mid-depth buoys with 49 artificial reef modules, providing more than 27000 m3 of habitat. Once support structures for subsea facilities, the decommissioned assets are now important habitat features that increase ecosystem productivity. The unique design and configuration of the structures on the sea floor resulted in a rapid increase in the diversity and abundance of marine biota, as detected by a collaboration between citizen scientists and researchers. Within 2 years, over 90 species of fish have already been observed, which is much greater than the sand habitat upon which the reef was installed. The results contribute to informed discussions, about the viability and effectiveness of artificial structures providing industry, regulators and the community with confidence around the benefits and effects of various installations. The Exmouth community has been advocating for the installation of an artificial reef for several years. At King Reef, the integration and repurposing of assets provide a range of long-term benefits to communities, including fostering community ownership and stewardship of these assets while providing new, safe and accessible fishing and diving opportunities.

No abstract

There has been a marked increase in the number of artificial reefs being deployed around the world, many of which are designed to increase catches of recreationally-targeted fish species. As artificial reef deployments should be accompanied by clear and measurable goals and thus subsequent environmental impact monitoring and performance evaluation, there is a need to develop cost-effective monitoring programs. This study provides proof of concept for a citizen science approach to monitoring the fish faunas of artificial reefs (Reef Vision). Recreational fishers were recruited to collect video samples using Baited Remote Underwater Video systems and submit the resultant footage for analysis and interpretation by professional scientists. Reef Vision volunteers were able to collect enough data of sufficient quality to monitor the Bunbury and Dunsborough artificial reefs in Geographe Bay, south-western Australia. Data were extracted from the footage and used in robust univariate and multivariate analyses, which determined that a soak time of 45 min was sufficient to capture ≥ 95% of the number of species, abundance, diversity and composition of the fish fauna. The potential for these data to detect differences in the characteristics of the fish fauna between reefs and seasons was also investigated and confirmed. With the continuing deployment of artificial reefs around the world, the use of similar cost-effective citizen science monitoring approaches can help determine the effectiveness of these structures in achieving their aims and goals and provide valuable data for researchers, managers and decision makers. Projects such as Reef Vision can also benefit volunteers and communities by enhancing social values, creating ownership over research projects and fostering stewardship of aquatic resources.