A study conducted by the Water Research Commission in South Africa has indicated that there are 52 thermal springs suitable for aquaculture research and development. Although this potential has been expressed, thermal springs in South Africa have yet to be utilised for aquaculture purposes. The advantage of using a thermal spring is that heated water will be available for warm-water aquaculture all year round. C onventional warm-water aquaculture systems are usually limited to a six-month (per year) production period due to the unfeasibility of artificially heating water during colder winter months. A geothermal spring at Brandvlei Correctional Centre in Worcester in the Western Cape, has been identified as a launch site for a thermal water aquaculture pilot study. The water at the site is safe to use, and also has constant high temperatures (64°C) and fast flow rates (127 L/s) which would support the culture of warm-water fish (i.e. tilapia or catfish), all year around.
This project aims to determine whether the Brandvlei spring can be utilised successfully for warm-water aquaculture; with special focus on the potential cost-savings that are achieved, in comparison to a conventional system where artificial heating is used. The project will run for a period of 12 months, in which required permits and permissions will be obtained, and a small energy-efficient test-system will be set up on-site. Some research and development (i.e. cooling methods ) will be necessary with regards to the introduction of the spring water into the test-system, as the spring water emerges from the ground at 64°C and tilapia (Oreochromis niloticus ) requires a water temperature of 28-30°C for optimal husbandry and performance. This method will be developed with the aim of maximising efficiency, while minimis ing power consumption and cost. Once the test-system is up and running, and tilapia fingerlings have been introduced, a training workshop will be held to provide training to students and members of the Brandvlei Correctional Centre to promote aquaculture skills development and provide practical experience in the test-system itself.
A co-management plan will then be drafted between Stellenbosch University , Brandvlei Correctional Centre, Department of Public Works and Department of Water and Sanitation to ensure the continued maintenance of the aquaculture system for future successful harvests and exploring commercial opportunities for at other geothermal sites in South Africa. The project has started in April 2021, and authors will share challenges and progress to date.