Title : Ecological cage aquaculture in quarry lakes: A post-mining strategy in Buenos aires, Argentina
Abstract:
Freshwater ecological aquaculture of Odontesthes bonariensis in floating cages—whose success has been demonstrated through the regular production of thousands of individuals for restocking purposes—is an ecosystem-based strategy with the potential to promote regional economies while minimizing environmental impacts. This approach builds on the appeal of this emblematic native species of the Province of Buenos Aires, Argentina, and has been developing in shallow lakes for the past twenty years. More recently, the focus has shifted toward sustainable use strategies for quarry lakes: water-filled excavations resulting from the extraction of soil, rock, or other geological materials, formed after mining operations cease, due to increase of groundwater table, surface water runoff, and/or precipitation. In Buenos Aires Province, there are approximately one thousand quarries, about 300 of which are flooded, many located within or near urban areas. These are considered environmental liabilities, posing challenges for numerous municipalities. However, these sites also present unique characteristics that make them suitable for implementing innovative post-use strategies, such as collaborative and ecosystem-based aquaculture projects for native fish species. Recognizing aquaculture as a means to enhance local quality of life, four experiments have been conducted since 2022 in a quarry lake in Samborombón (Brandsen, Buenos Aires). These involved floating cages built and installed in collaboration with local stakeholders. Those experimental units, of 12 m3 in volume, were designed based on prior experience and stocked with pejerrey of different ages. The outcomes of these experiments have informed decisions that significantly improved fish growth, achieving the highest growth rates ever recorded for the species using these methods. Key improvements included optimal cage positioning and introducing an innovative pumping system as a technological adaptation. Using simple and low-cost techniques, and in dialogue with the local community, the goal for the coming years is to promote the co-construction of scientific and technological knowledge with a tangible impact on the local landscape. This sustainable approach could be replicated in other quarry lakes across the region.
