Assessing effects of water treatment systems on aquatic microbial communities in eel aquaculture (CLEANEEL) (39801)

Project Details


Aquaculture is currently the fastest growing food-producing sector in the world, yet the majority of successful aquaculture comes from a small number of species. Successful cultivation of marine pelagic fish is known to be highly dependent on their early life stages – where they are highly vulnerable to bacterial infections – and for many species this remains a big challenge.

The European eel is one such species which is very important yet commercially underdeveloped, as they cannot yet be farmed independent of wild stocks. Current methods rely on catching wild young glass-eels for culturing to market size, which is both unsustainable and market-limiting. A major gap in their sustainable farming lies in the survival and growth of eggs and larvae into these glass eels. During early life stages in the wild, they are exposed to oceanic environments that are very low in microbial activity and outside of these environments they have been shown to be highly vulnerable to bacterial infections due to an immature adaptive immune systems. Bactericidal treatments show a short term remedy, though they are unsustainable and non-selective, also killing beneficial bacteria and potentially allowing opportunistic bacteria to flourish.

Therefore, a stable microbial community within aquaculture systems has been highlighted as a requirement for a stable production of European eel offspring. One such way to control bacterial levels of culturing water is through specific water treatment.

SANI Membranes A/S and NORLEX A/S both operate SMEs in the capital region of Copenhagen, where they specialize in custom water treatment applications for drinking water such as advanced oxidation and customized membrane designs. They are interested to explore an expansion into the aquaculture water treatment market, where a collaboration with DTU will enable pilot testing of their treatment systems for European eel cultivation. Due to the high sensitivity of eel eggs and larvae, they also provide an excellent model species for investigating the effects of different microbial communities on fish egg hatching and larvae survival in general.

Specifically, the project CLEANEEL aims to control the aquatic microbial communities through water treatment. By manipulating water character through treatment, we aim to identify those which enable stable and beneficial microbial communities that can be reliably created within a controlled RAS, and ultimately lead to enhanced egg hatching and larvae survival.

Three different types of seawater treatments (provided by SANI Membranes and NORLEX SYSTEMS) will be applied to early life stages of eels, which will then be assessed in terms of embryo and larval survival, water stability, microbial development, and carbon dynamics. The treatments will be combinations of microbial maturation, ultrafiltration, ozonation, and UV. The work will take place at DTUs Eel Hatchery aquaculture facility in Hirtshals, with water sample analysis for microbial communities, carbon and nutrient content, to take place at both DTU Hirtshals and DTU Lyngby Campus.

National Institute of Aquatic Resources, DTU Aqua (coordinator)
Department of Environmental Engineering, DTU Environment
Sani Membranes A/S, Denmark
Norlex A/S, Denmark

The project is funded by WISE (Water, Innovation, Small medium sized Enterprises).

Research area: Fish Biology
Research area: Aquaculture

Effective start/end date22/06/202001/10/2020


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