An Integrated Monitoring Approach to the Evaluation of the Environmental Impact of an Inshore Mariculture Plant (Mar Grande of Taranto, Ionian Sea)

SIMPLE SUMMARY: The importance of aquaculture for providing animal proteins to a steeply increasing world population is growing. Despite the many benefits from this practice, there are also many constraints. Among them, the eutrophication of seawater and unsustainability are of the utmost importance. Integrated multitrophic aquaculture (IMTA), consisting of the co-farming of organisms of different trophic levels, was conceived to overcome these problems, and it is still developing to reach sustainable practices. In the Taranto seas (southern Italy, Mediterranean Sea), the first attempt of an IMTA plant with fish, mussels, polychaetes, sponges, and seaweeds started within the framework of the REMEDIA-LIFE project. This plant was arranged in a pre-existing fish farm where the European seabass Dicentrarchus labrax and the sea bream Sparus aurata are bred in net cages. Here, we report the results of the ex-ante evaluation of the trophic conditions of the seawater around the plant, which is useful for assessing the bioremediation effectiveness of the IMTA action after its implementation. ABSTRACT: The results of an ex-ante survey aiming to assess the impact of a fish farm in the Mar Grande of Taranto (southern Italy, Mediterranean Sea) on the surrounding environment are reported. There, the implementation of an innovative IMTA plant was planned, with the goals of environment bioremediation and commercially exploitable biomass production. Analyses were conducted in February and July 2018. Both seawater and sediments were sampled at the four corners of the fish farm to detect the existing biological and physico-chemical features. The investigation was performed to identify the best area of the farming plant for positioning the bioremediating system, but also to obtain a data baseline, to compare to the environmental status after the bioremediating action. Data were also analyzed by canonical analysis of principal coordinates (CAP). All the measurements, in particular, microbiology and macrobenthic community characterization using AZTI’s Marine Biotic Index (AMBI) and the Multivariate-AMBI (M-AMBI) indices, suggest that the effect of fish farm waste was concentrated and limited to a small portion of the investigated area in relation to the direction of the main current. A site named A3, which was found to be the most impacted by the aquaculture activities, especially during the summer season, was chosen to place the bioremediation system.