This study confirms the potential of Hediste diversicolor as a sustainable tool for bioremediation in beluga sturgeon aquaculture, promoting circular practices within integrated multi-trophic aquaculture (IMTA) systems. The polychaete efficiently converts fish waste into nutritionally valuable biomass due to its trophic plasticity and resilience. Waste-fed worms produce viable biomass, though with lower nutritional quality (e.g., PUFA content) compared to those fed commercial feed.Key findings include the importance of density optimization: low densities (1000–2500 ind./m²) is ideal for producing large, high-quality worms for premium markets like bait, while high density (5000–7500 ind./m²) is better suited for waste treatment and bulk biomass production. Nutritional quality, particularly PUFA content, can be enhanced by supplementing diets with lipids from microalgae or oils, maintaining. Based on the successful validation of H. diversicolor as a sustainable bioremediation tool for aquaculture, this study provides a concrete pathway toward more circular practices. The worm is an exceptional candidate for IMTA due to its ability to directly convert fish waste into nutritionally valuable biomass through its trophic plasticity and resilience. The research offers a scalable model centered on density optimization and dietary enhancement. For the primary goals of waste treatment and producing bulk biomass, a higher density of 5000-7500 ind./m² is optimal.
This model provides a scalable solution to reduce aquaculture's environmental impact and create economic value from waste.
 

Bioremediation, polychaete culture, waste valorization, IMTA