Efficiency of Artificial Reefs for Local Communities Over Time

Introduction

From the point of view of efficiency, when designing an artificial reef (AR), several objectives to be achieved after the implementation of the structures must be anticipated (Seaman & Jensen, 2000; Ramm et al. 2021). To achieve efficiency in the project, it is equally important to consider from the beginning that a good development of the entire process will have to include the set of stakeholders interested and involved in the initiative, the monetary funds available, the geographic areas with potential for use and the selection criteria to be used (Claudet & Pelletier, 2004). The selection criteria cover several aspects such as: not only construction materials, size, or performance of the structures (Kim et al., 2021) and their typology (e.g., modules or ex-vessels), but also what purpose will the structures serve, what type of users will be covered, and which are the rules to follow to an adequate management of the areas where the structures were sunk (Bohnsack & Sutherland, 1985; Tunca et al., 2019). After all these initial assumptions have been considered, the modular construction or reuse of the structures is done, and the reef deployment is consummated (Martin, 2004).

Sometime after the reef deployment – that is, during the structure maturation process – it is convenient to verify to what extent the initially proposed objectives have been achieved. This long process makes it possible to determine whether the reef deployment has been efficient, either from a structural, ecological, social, or economic point of view, or another that has been defined (Seaman, 2000).

For example, as the deployment of reefs essentially consists in the creation of three-dimensional spaces that can mimic the habitats of certain organisms, what is initially done to verify the success of the deployment of reefs is to carry out scientific research on the progressive achievement of the colonization of living marine resources (Holland et al., 2021). It is of great importance to get answers to questions related to the types of living marine organisms that colonize the reefs in each geography and depth, or what type of ecological arrangements are formed on the different sides of the reef, regardless of if they are modules or another type of structures (Choi et al., 2002). This monitoring is essential, as if there is not an adequate colonization, this fact can be an indicator of a possible problem (Kolian et al., 2017). In such a case, reef efficiency is called into question.

After verifying reef colonization and evaluating its eventual biological and ecological success, it is important to understand how AR are accepted by potential human users (Adams et al., 2006). In turn, these potential users will empirically assess the usefulness of the structures relating them to the satisfaction achieved in their own activity, whether professional or recreational (Layman & Allgeier, 2020). The income derived from businesses that may eventually operate taking advantage of the reef's surplus value, enter in this process of assessing the efficiency of AR (Fletcher et al., 2011). For instance, it is possible to find the average wage that each worker in the primary sector earns (i.e., small-scale fisheries). The diversification of tourist activities of companies that promote sport fishing and leisure diving can also be evaluated. The efficiency of reef structures derives from the surplus that these firms will take from having more choice options to offer their clients (Monteiro, 2016).

The existence of high biodiversity in these reef structures is a fundamental factor to assess and consider the issue of ecological efficiency (Huddart, 2019). There may also be factors with a more negative predisposition that may influence a good performance in the efficiency of AR. These types of negative factors can often be related to siltation caused by undercurrents on some structures, or fishing gear that has been stranded or lost on some modules (Barber et al., 2009). In both cases there is a latent loss of reef efficiency. In these cases, it is essential to have an adequate identification of the problem and steps should be taken for a reef maintenance (Roseman et al., 2017).