Artificial reefs in the Anthropocene: a review of geographical and historical trends in their design, purpose, and monitoring

Abstract

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.

Quantifying spatial extents of artificial versus natural reefs in the seascape

“…These structures include artificial reefs, energy extraction infrastructure, and shoreline installments (Heery et al, 2017). Artificial reefs, for example, are deployed for a variety of purposes, such as enhancing or supplementing existing habitat, restoring degraded habitat, providing opportunities for fishing and diving recreation, or mitigating environmental impacts (Seaman, 2007;Becker et al, 2018;Lee et al, 2018;Ramm et al, 2021). Energy extraction infrastructure includes structures, such as wind turbines, tidal power extraction devices, and current hydrokinetic energy, that extract renewable energy (Miller et al, 2013), as well as infrastructure required for oil and gas production (Claisse et al, 2014).…”

Biodeterioration and Chemical Corrosion of Concrete in the Marine Environment: Too Complex for Prediction

“…Although in use by mankind for thousands of years, artificial reefs are now being increasingly considered as possible answers to the diminishing biodiversity in coastal ecosystems [106][107][108][109][110][111]. They are not always made of concrete, natural rocks, or other materials often being used.…”

Developing and integrating enhancement strategies to improve and restore fisheries

“…Blount et al (2021) propose guiding principles for the development of artificial reef programs from an ecological perspective, building on a review of the literature and emphasizing the potential for need for systematic reviews to support implementation of principles. Ramm et al (2021) assembled a database of artificial reefs as a basis for systematic reviews and meta-analyses. They further presented a standardized protocol for describing artificial reefs in published studies and urged authors to include the relevant data to allow future comparisons to enhance our understanding and evaluation of these structures.…”