GIS modeling of potentially suitable sites for aquaculture development in the Lake Tana basin, Northwest Ethiopia

Abstract

Background: Small-scale pond aquaculture has been practiced in various parts of the Lake Tana basin. However, its establishment and expansion have been carried out regardless of the suitability of the locations in terms of land, water, socioeconomic and other inputs available to the aquaculture development. In recent years, there is also an increased demand for aquaculture product, and the government and other private institutions have given much attention to the sector. In response to this need, it is necessary to evaluate the potential sites for aquaculture suitability based on biophysical and socioeconomic indicators. Consequently, GIS-based site suitability analysis was conducted at the basin level to identify and delineate areas, which are suitable for inland pond aquaculture, mainly for Nile Tilapia (Oreochromis niloticus). About 21 criteria, which are sub-grouped into socioeconomic, farm inputs and land use types, water availability, water and soil quality, and urban markets, were considered for aquaculture suitable site-selection analyses. They are converted into various thematic layers. The layers, then combined to develop their respective sub-model suitability maps, which in turn grouped to produce the final overall suitability maps using the weighted linear combination. The relative weights were generated through pairwise comparison by the analytical hierarchy process. Results:The analysis indicates that the prevailing situation in the basin supports promising opportunity for the establishment and development of aquaculture. The GIS evaluation predicts that out of the total land identified for aquaculture site, 32,678.9 ha (2.7%) is highly suitable, whereas 1,166,594.5 ha (97.2%) is moderately suitable for smallscale pond aquaculture system. Similarly, the considerable part of the basin was moderately suitable with a total area of 1,183,253.0 ha (98.6%) and more than 1% (16,768.2 ha) was highly suitable for commercial aquaculture farming. The land area delineated for the marginally suitable category was negligible in both cases.Conclusion: Therefore, the result confirms that the Lake Tana basin has sizeable potential room for aquaculture development at small-scale and commercial production levels.

Land Suitability for Sustainable Aquaculture of Rainbow Trout (Oncorhynchus mykiss) in Molinopampa (Peru) Based on RS, GIS, and AHP

“…The key advantages of MCE techniques are that they are well established for aquaculture zoning, they can combine multiple criteria (many more than those used in this study; [19,20,55]), and may develop models under different hierarchies, priorities, and scenarios [8]. However, the main problem in the analysis of land suitability for aquaculture in ponds dug in the soil, and in general for any activity, lies in the lack of spatial data of the criteria [16].…”

“…Despite this being stated, no such approach was applied, because it depends on the georeferenced locations of the fish farms, and even though SDM such as MaxEnt has an extremely small sample size tolerance [69], it was considered inappropriate to use only the five farms, as it could affect the performance of the model. For further studies, the additional confidence that a combined approach to MCE and SDM would bring would be of vital importance The key advantages of MCE techniques are that they are well established for aquaculture zoning, they can combine multiple criteria (many more than those used in this study; [19,20,55]), and may develop models under different hierarchies, priorities, and scenarios [8]. However, the main problem in the analysis of land suitability for aquaculture in ponds dug in the soil, and in general for any activity, lies in the lack of spatial data of the criteria [16].…”

“…The identification of the potential area for aquaculture should be based on favorable criteria to allow the growth of species of interest [5]. These criteria were established by considering rainbow trout breeding manuals from Peru [36] and FAO [37], land suitability studies for rainbow trout aquaculture [17,18], aquaculture of other species [8,16,19,[24][25][26], and the criteria for aquaculture zoning set by the FAO [5,13]. The same ones that were validated for the planning process by a group of experts, made up of five fish farmers in the study area and six aquaculture specialists from the DIREPRO-A of the PRODUCE.…”

“…To develop the third hierarchy (Figure 3), the criteria were reclassified and scored on a categorical scale of four levels of suitability [16,19,25]: "Very suitable" (4), "Moderately suitable" (3), "Marginally suitable" (2), and "Not suitable" (1). This stage was based on bibliographic review and consultation with an expert group to adapt the suitability thresholds for each sub-criterion to the local environmental condition [5] (Table 1).…”

aquaZone: An Integrative Tool for Sustainable Fish Farm Zoning

“…Therefore, we performed a literature review on frequently used criteria for aquaculture operation and siting. While most studies showed a clear focus on environmental criteria, some also incorporated social and economic parameters [34][35][36][37].…”