Artificial Reefs around the World: A Review of the State of the Art and a Meta-Analysis of Its Effectiveness for the Restoration of Marine Ecosystems

Abstract

Over the past decade, there has been increasing interest in marine restoration, requiring a consideration of various approaches for optimal success. Artificial reefs (ARs) have been employed for marine restoration and fisheries management, but their effectiveness in restoring ecosystems lacks well-defined ecological criteria and empirical evidence. A systematic review of the literature on ARs articles between 1990–2020, a meta-analysis of their effectiveness based on the similarity of species composition with reference natural reefs (NRs), as well as bias risk analyses were carried out. Research on ARs primarily focused production of marine communities (n = 168). There are important information gaps regarding socioeconomic aspects; design, materials, and disposal in the selected habitats; legal, management, and planning aspects considering long-term monitoring. Regarding effectiveness, few articles (n = 13) allowed comparisons between ARs and NRs, highlighting the need to apply proper reference sites in AR implementations. Meta-analysis showed that ARs are not similar to reference NRs (p = 0.03, common effect and p = 0.05 random effect models). However, a high index of heterogeneity (88%) suggests that this relation may be influenced by factors other than the reef type. Thus, further analysis can disguise variables conditioning this AR–NR similarity as a measure of restoration for degraded marine ecosystems.

Catalyzing Conservation: An Analysis of Fish Stock Dynamics in a Marine Protected Area before and after Artificial Reef Deployment

“…Several studies have researched artificial reefs for aspects like abundance, biomass, and species diversity [21,22]. However, using a species composition index is more advisable to prevent skewed interpretations of effectiveness [23]. The evaluation of the ARs' impact on restoration, using genuinely comparable and appropriate reference sites, is scarce.…”

Habitat Fragmentation Enhances the Difference between Natural and Artificial Reefs in an Urban Marine Coastal Tract

“…If the primary goal of artificial reef construction is the creation of additional reef habitat for fish, it should be considered that their assemblages will likely differ significantly from those of adjacent natural reefs, also depending on the rock type of the latter compared to the materials used for the former [25]. Artificial reefs have also been employed for marine restoration, although their effectiveness in restoring ecosystems lacks well-defined ecological criteria and empirical evidence [26]. However, there is increasing evidence that the epibiota thriving on artificial reefs is often distinct from that found on natural reefs [2], not only in terms of epibenthic assemblage composition but also in terms of trophic function: suspension feeding typically dominates natural reefs, while within artificial reefs, there may be an ascendency of carnivory [27].…”

Pre-study of the evaluation of ecological sessile succession and their relationship with bacteria on concrete artificial reef material

“…Although some sectors such as fishing, transportation and tourism directly benefit the sea, the developing industrial sector poses a significant problem for the marine ecosystem. Moreover, practices such as landfilling, littering, illegal fishing activities and the global effects of climate change lead to the loss of underwater habitats (Brander, 2013;Bracho-Villavicencio et al,2023;O'Reilly and Willerth, 2024). These damages to water quality and habitat opportunities lead to irreparable damage to the aquatic ecosystem balance.…”

“…Especially, to improve damaged habitats and support the ecosystem many scientific studies are carried out and various tools and methods are used (Borja et al 2020). Artificial reefs are also among the tools used for this purpose (Toring-Farquerabao et al 2021;Bracho-Villavicencio et al 2023). Artificial reefs, which are frequently used for habitat restoration especially on the Mediterranean coasts, have been implemented in more than 70 applications on the coasts of our country.…”

“…Succession features are critical in realizing this expectation. It is extremely important to monitor the processes developing on the reef in the long term from the moment the artificial reef material first contacts with the water and to determine the efficiency of the application in order to reveal whether the targeted goals are achieved (Bracho-Villavicencio et al 2023).…”