Safeguarding future production of fish in aquaculture systems with water recirculation

Globally, aquaculture is the fastest-growing animal food sector and today almost half of the World´s consumption of all fish products originates from aquaculture. However, high water consumption and nutrient release from fish farms cause environmental and public concern. This has led to development of fish breeding in systems with water recirculation, named RAS. RAS technology reduces the water consumption, but reuse of the water causes problems with respect to maintaining a high water quality, even when various water treatment approaches are used. In the RASOPTA project, new technologies for improvement of the water quality by reducing nutrients, controlling abundance of harmful bacteria and parasites, will be developed. To ensure a high welfare of the fish, stress level of the fish will be monitored, and for biosecurity reasons, potential spreading of pathogenic virus and bacteria from RAS farms will be examined. A major concern in RAS is microbial production of earthy off-flavours that accumulate in fish and reduce their consumer attractiveness. Occurrence of these microbes will be analysed to develop mitigation procedures. To ensure marketing of tasty fish with RAS technology, sensory and instrumental methods will be applied to determine ideal rearing conditions for optimum taste. For prediction of water quality and health issues in RAS, a DNA-based chip will be developed to allow an early warning of emerging problems in operating RAS. These research goals will be accomplished through interdisciplinary and university-industry driven research training by 8 universities, 3 research institutes and 8 companies. By combining new approaches within microbial ecology, molecular biology, bioinformatics and analytical technologies, the project will deliver solutions to remove barriers that restrict expansion of the innovative and highly efficient RAS fish production.

The training goal of the RASOPTA training is to educate 12 ESRs in state-of-the-art technologies in RAS production to create a new generation of highly skilled young researchers within aquaculture disciplines. The research training is conducted in 3 tightly-connected work-packages (WPs) that combine academic expertise with hands-on experiences from the RAS industry within production of important aquaculture species on the European market: salmon, rainbow trout, pike-perch and sturgeon (for caviar production).

WP1. New technologies for upgrading of the water quality in RAS by optimizing biofilters for improved microbial and chemical water quality; quantification of the biological role of micro-particles that typically are abundant in water in RAS; and determination of the impact of microbes in the water to the fish microbiome.

WP2. Identification of dominant off-flavours in water and fish from freshwater and marine RAS; location of hotspots and microbial ecology of the off-flavour producing microorganisms; test of conventional and new prototypes of fish feeds for content of off-flavours; and isolation of off-flavour degrading bacteria that can assist in elimination of off-flavour episodes in RAS.

WP3. Control of the abundance of common disease-causing bacteria and parasites in fish in RAS; evaluation of fish welfare in intensive fish production systems; establishment of safe procedures for biosecurity; and design of a DNA-based chip as an early warning tool for typical health and water quality hazards in RAS.

The fellowship is funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 956481.