Holothurians play an important role in mitigating the impacts of aquaculture on sediment conditions

As deposit feeders contribute to bioremediation and nutrient recycling in sediments, positively impacting water and sediment quality, holothurians are candidate organisms for multitrophic aquaculture. This study aimed to investigate the potential of Holothuria poli to reduce the environmental footprint of fish farms through a benthocosm experiment. The experimental setup included four benthocosms with holothurians(H+) and four without (H-). The 58-day experiment included two phases: constant organic enrichment and recovery. In order to simulate the organic enrichment sediment conditions under a typical fish farm, a mixture of fish feces and fish feed pellets was added. Results showed that holothurians effectively reduced organic matter and H₂S and increased redox, RPD depth and sediment oxygenation, thereby preventing anoxic conditions. Also, during the recovery phase, holothurians facilitated rapid sediment recovery, while the sediments without holothurians remained organic-enriched until the end of the experiment. The study emphasizes the significance of holothurians in mitigating the impacts of aquaculture on sediment conditions and so promoting environmental sustainability.