The development and use of a GIS model to map Mozambique tilapia pond aquaculture site suitability for the Limpopo province of South Africa

Abstract

The fast-growing population, globally, in Africa, Sub-Saharan Africa and South Africa, could lead to food insecurity. One solution to this challenge is that aquaculture can provide alternative sources of food and protein and increase job-creation and income to especially small-scale rural pond aquaculture farmers to ultimately improve food security in South Africa. Pond aquaculture could offer an alternative solution to overfishing of the dwindling wild fish stocks. The South African government has established numerous aquaculture funding initiatives, like Operation Phakisa and the National Development Plan (NDP) 2030 in place but requires information as to where to spend and allocate their resources effectively and optimally. The main aim of this study was to create a Mozambique tilapia (Oreochromis mossambicus) pond aquaculture site suitability model for the pilot study area, the Limpopo province of South Africa. The model should however be a general model which could be used for the whole of South Africa. The model was designed in a Geographic Information Systems (GIS) which could be used to create suitability maps. The importance of this study is that it could indicate to Government where to focus their funding and other support. By focussing their funding only on new or current enterprises and farmers in highly suitable areas, funders could be sure that only the more efficient producers and areas were supported. This could ensure that their financial aid would lead to increased return on investment, accelerating aquaculture and increasing food security in South Africa. The choice of this fish species and pilot study area, the Limpopo province of South Africa, is since the Mozambique tilapia is a warm-water, palatable fish, suitable to pond aquaculture. Pond aquaculture is relatively simple and cheap to start-up and maintain. The Mozambique tilapia is endemic to the Limpopo province of South Africa. The suitability products and -maps were also used to score and rank 48 existing tilapia farmers, to showcase that top-scoring farmers in the highly suitable areas could be identified so that fiscal and other support could be focussed on them. The research findings indicated that the GIS site suitability model, which was created in a Multi-criteria Evaluation (MCE) environment, had generated many sub-model intermediate suitability products which fed into the two final suitability products for the Limpopo province of South Africa. The final suitability products were the Weighted Overlay (WO) suitability integer raster and the Weighted Sum Overlay (WSO) suitability floating-point raster. These rasters were classified to produce suitability maps which could indicate to Government, other stakeholders and funders where to sustainably invest limited resources on only highly suitable areas, from provincial- to farm-scale. From the results of the WO suitability product, the Limpopo province suitability was tabulated to indicate the area and percentages of every suitability class, namely Highly suitable (16%), Moderately suitable (31%), Marginally suitable (13%), and unsuitable or restricted/ constraint areas (39%). The 48 existing farmers’ GPS locations were used to score and rank them according to their suitability using the floating-point WSO product. This was done to identify the farmers that were ranked the highest suitability to justify the distribution of limited funding. The results from extracting the Weighted Sum Overlay (WSO) of the GPS locations of the existing 48 farmers, were encouraging; as 50 percent of the farmers were already located in Moderately suitable areas, 35 percent of farmers were situated in Highly suitable areas and only 15 percent in Marginally Suitable areas. From the Weighted Overlay (WO) extraction, most farmers (56 percent) found themselves in Moderately suitable areas, 27 percent in Highly suitable areas and 17 percent in Marginally suitable areas. It was investigated whether using a GIS for Mozambique tilapia pond aquaculture site suitability allocation was faster and cheaper than other methods. It was established that farmers in highly suitable areas produced more efficiently, and that these farmers produced more fish more sustainability. Funding these mostly small-scale farmers could increase their livelihoods, and increase household income, of which many are female-headed, and increase production of fish via roll-out of the model to other provinces. This would accelerate aquaculture in South Africa and assist in increasing food security for its growing population. Recommendations from this research include research findings that are very clear that the government of South Africa and funders should ensure that their investments were optimised by annually, (not once-off) adding the following to the chosen farmers or pond tilapia enterprise owners: Consistent training (by government also via extension officers) as well as credit facilitation and funding and the encouragement of private public cooperation. Recommendations for further study include the use of the AQUASUIT Suitability App for querying suitability of points and areas, the roll-out of the use of the model to other provinces, the insertion of climate change Global Circulation Models’ data into the model to provide future-suitability maps and to delineate Mozambique tilapia sanctuaries and breeding sites.