Waterbody scale assessment using spatial models to identify suitable locations for cage aquaculture in large lake systems: A case study in Volta Lake, Ghana

Abstract

Large lakes throughout the world offer development opportunities for cage aquaculture. However, due to their vast area, identifying the most suitable locations can be a challenge. This is also complicated as lake systems are often multi‐use environments, so a strategic approach to managing the resource is required. This study uses geographic information systems (GIS) to develop a broad‐scale approach that identifies potential areas that may be suitable for cage aquaculture development. Volta Lake, one the world's largest man‐made lakes, is used as a case study. The overall GIS model combines four sub‐models, bathymetry, hydrography, water quality and access, and a constraints layer, to identify the most suitable locations for tilapia production. Three different cage sizes are modelled: small, medium and large. The model outputs suggest that approximately 102 km2 (1.7%), 406 km2 (6.9%) and 407 km2 (6.9%) of Volta Lake can be categorized as highly suitable for development of small, medium and large cages respectively. A further 634 km2 (10.8%), 1264 km2 (21.4%) and 1055 km2 (17.9%) can be categorized as suitable for the same. The results can be used by stakeholders and decision makers to identify specific areas where aquaculture development for cage farming of tilapia could be prioritized.