Pond Circle

Funding Program and Background

Fish farming in ponds is of great economic, infrastructural and ecological importance in Central Europe. However, climate change is leading to shifts in rainfall patterns and extreme rainfall events, which can impair pond functions, for example due to the build-up of sediment from soil erosion. The nutrients released from the sludge, combined with higher temperatures, trigger algal blooms, oxygen depletion and nutrient emissions. This project aims to reduce eutrophication in ponds using natural nutrient sorbents, which are extracted from the ponds prior to harvesting. The study will investigate the extent to which natural nitrification inhibitors can enhance adsorption. This innovative approach could reduce the build-up of the sludge layer, increase water retention capacity and lead to improved regional water management. The innovation would reduce nutrient emissions into receiving waters (e.g. rivers) and the atmosphere. The nutrient-rich sorbents can be sold as fertiliser, thereby strengthening the circular economy. To address the challenges outlined above, the expertise of the project partners, the target group and regional aquaculture SMEs of varying sizes on both sides of the border is required. Through this collaborative project, a solution can be tested in both regions to derive recommendations for pond areas across the EU and to increase pond farmers' incomes.

With the help of natural nutrient sorbents and potential nitrification inhibitors, the build-up of the sludge layer is reduced, enabling ponds to contribute more effectively to regional water managementment. Lower nutrient emissions reduce the burden on transboundary natural water bodies and the air. This contributes to Specific Objective 7, 'Improving the protection [...] of nature [...]', as the near-natural, blue infrastructure of extensive ponds is preserved. These ponds often form the cornerstone of Natura 2000 and FFH sites in the Bavarian-Czech border region and, in some cases, are home to more Red List species than river floodplains. As the silting up of the ponds is reduced, fewer costly land improvement measures are required. Water quality in the ponds and in the receiving waters (streams, rivers) remains at a high standard, enabling sensitive fauna and flora to retain or re-explore their habitat within the ecosystem. SME fish farms can produce more cost-effectively and gain a new source of income.