The Worm That Could Change Fish Farming
PhD defence, Thursday 10th of September 2026, Mathias Engell Dahl Holmstrup
As the demand for farmed fish increases, aquaculture needs better and more sustainable ways to rear young fish. In his PhD project, Mathias Holmstrup investigated the potential of the white worm, Enchytraeus albidus, as a new live feed organism for aquaculture.
The research showed that the worms can improve growth in juvenile fish such as rainbow trout and European flounder compared with conventional dry feed. The project also improved large-scale production methods and explored whether the worms’ natural ability to survive freezing can be used for long-term storage.
By studying how temperature, salinity and storage conditions affect survival during freezing, the project identified conditions that allow the worms to be preserved for extended periods while remaining viable after thawing.
The results demonstrate that E. albidus has the potential to become a valuable live feed organism for aquaculture and may help make fish production more efficient, sustainable and less dependent on traditional live feed sources.
The PhD study was completed at Department of Ecoscience, Faculty of Technical Sciences, Aarhus University.
This summary was prepared by the PhD student.
Time: Thursday, 10th of September 2026 at 13:00
Place: Building 1110, Room 223, Department of Ecoscience, Aarhus University, C. F. Møllers Allé 4, 8000 Aarhus C. Followed by reception in room 414 (lunchroom).
Title of PhD thesis: Enchytraeus albidus as Live Feed in Aquaculture: Suitability for Juvenile Fish and Cryopreservation
Contact information: Mathias Engell Dahl Holmstrup, e-mail: MEH@fishlab.dk, tel.: +45 27144935
Members of the assessment committee:
Professor Hans Ramløv, Department of Science and Environment, Roskilde University, Denmark.
Professor Jorge Domínguez, GEA (Grupo de Ecoloxía Animal), Universidade de Vigo, Spain.
Professor Christian Frølund Damgaard (chair), Department of Ecoscience, Aarhus University, Denmark
Main supervisor: Senior Researcher Stine Slotsbo, Department of Ecoscience, Aarhus University, Denmark
Co-supervisor: Industrial researcher Kirsten Engell-Sørensen, Fishlab, Denmark
Language: The PhD dissertation will be defended in English
The defence is public.
The PhD thesis is available for reading at the Graduate School of Technical Sciences/GSTS, Ny Munkegade 120, building 1521, 8000 Aarhus C.