## 4 Discussion
The Multi-Criteria Evaluation (MCE) method was employed to optimize the selection of sites appropriate for sturgeon farming on the southern coast of the Caspian Sea, in Golestan, Iran. In this approach, the MCE was weighted using the Analytic Hierarchy Process (AHP) and combined with the Weighted Linear Combination (WLC) approach [83]. Reference [84] also applied this method to the survey of areas for the development of shellfish farming in Souahlia Bay, in Algeria. A multi-criteria approach was used to identify sites that were adequate for fresh- and brackish water fish farming on the coastal plains of the Indian states of Odisha and Tamil Nadu. For this, they used large scale (1:10,000), high resolution maps of land cover and use, with thematic layering and regulations [85]. Reference [86] successfully applied a combined approach of Earth Observation (EO) and a dynamic energy budget (DEB) model for the selection of the most appropriate sites for the cultivation of the Pacific oyster, _Crassostrea gigas_, on the coast of South Africa. The sedimentological analyses carried out in the present study provided confirmation of the geophysical methods employed at the different study sites. The results of the SPT technique (Tables 1 and 2) validated the findings of the EMI and GPR tools (Table 3) on the lithological characteristics of the subsoil (Area 1). The relative dielectric constants and electromagnetic wave velocities of the geological substrates were determined as in Area 1 [38]. The lithological features identified in Area 1 were also corroborated using the Brazilian Geological Service (BGS) database on the subterranean waters of the study area [87], which correspond to the Barreiras Formation of the Neogene, in Area 1, formed by interlaced sandy-clayey and clay soils with medium to coarse sands, and the Quaternary in Area 2, with the intercalation of clayey and sandy-clayey soils, containing medium-grained sand. The sedimentological analysis of the soil samples confirmed that the substrates at the two study sites are appropriate for the construction of fish ponds, based on the recommendations of [57; 58]. The results of these analyses were also consistent with the results of the EM and GPR surveys. The present study confirmed the good performance of the geophysical tools for the diagnosis of terrains earmarked for fish farming. These tools identified favorable conditions in the subsurface at CEANPA (Area 1). These results supported the excavation of fifteen ponds (twelve for raising fish, two for the treatment of wastewater, and one reservoir) at this site in February 2020 (Figure 9), although this process was interrupted due to the COVID-19 pandemic and was only completed in December 2021 (Figure 3b). The initial excavations confirmed the findings of the geophysical survey and the sedimentological analyses. The maximum depth of these ponds is approximately 1.6 m (Figure 10). Ground Penetrating Radar (GPR) and Electromagnetic Induction (EMI) can be extremely valuable for the collection of spatial data that correlate with the soil types and hydrological properties of a terrain (e.g., [88; 89; 90; 91; 92]). The geophysical survey techniques employed in the present study have also been used to successfully investigate the physical properties of the soil and subsoil in research in scientific fields such as agronomy,  
Figure 10: The maximum depth of the ponds excavated in Area 1. Figure 9: Aquaculture operations in Area 1: **(a)** Installations; **(b)** Demarcation of the ponds; (c-f) Excavated ponds. archeology, hydrology, and wetland ecology (e.g., [23; 37; 88; 93; 94; 95; 96; 97; 98; 99; 100; 101; 102; 103; 104; 105; 106]). References [22; 107] predicted that the integration of geophysical tools (e.g., Electrical Resistivity Tomography (ERT), EMI, and GPR) with remote sensing will contribute to the successful development of precision agriculture.