Germinal vesicle in an oocyte of European eel. Photo: Michelle Jørgensen.

PhD defence on reproductive physiology of European eel

Thursday 04 Jun 20


Jonna Tomkiewicz
Senior Researcher
DTU Aqua
+45 35 88 34 08


The experimental research of this PhD project was performed as part of the EEL-HATCH and ITS-EEL projects, supported financially by Innovation Fund Denmark and ENV-“fonden”.  

Learn more about the EEL-HATCH project

Learn more about the ITS-EEL project

On 11 June 2020, Michelle Jørgensen, DTU Aqua, will defend her PhD thesis. The defence can be watched online.

Eels do not reproduce naturally in captivity due to complex control mechanisms at the brain-pituitary level that prevent sexual maturation. From a commercial perspective, this impedes closed-cycle production and development of sustainable aquaculture of this species that presently is critically endangered. Yet, assisted reproduction using hormonal treatment has enabled production of viable offspring, however, with variable reproductive success and quality of eggs. 

To improve our understanding of female eel reproductive biology, PhD Student Michelle Jørgensen, DTU Aqua, has studied characteristics of hormonally induced ovarian development and the production of yolk proteins in the liver (the so-called vitellogenesis) with emphasis on the regulation of physiological processes in the ovary and liver. The studies combine histology and molecular analyses with advanced genetic technology. 

Michelle Jørgensen’s work has substantiated insights into the regulation of genes and biological pathways during hormonally induced reproductive development. Furthermore, novel information about genes involved in reproductive processes in the ovary and liver has expanded our understanding on the complex regulation of these two organs and their interaction. 

The new findings do not only present possibilities for further studies on the reproductive physiology in eel. They also open for broader discussions on the regulation of vitellogenesis in fish and the applicability of advanced molecular technologies in aquaculture research.

Michelle Jørgensen will be awarded a Joint Doctorate Degree from Technical University of Denmark and Norwegian University of Science and Technology as the PhD project was conducted at both universities within the strategic alliance Nordic Five Tech.

About the defence

Michelle Jørgensen will defend her PhD thesis “Reproductive Physiology of Female European Eel” on Thursday, 11 June 2020 at 13:00 CEST.

The defence will be live streamed via Zoom video conferencing. For the link to join the defence please contact Rikke Hansen,, no later than 10 June 2020 at 14:00 CEST.


  • Principal supervisor: Senior Researcher Jonna Tomkiewicz, DTU Aqua
  • Principal supervisor: Professor Elin Kjørsvik, NTNU, Norway
  • Co-supervisor: Associate Professor Francesca Bertolini, DTU Aqua
  • Co-supervisor: Professor Einar Eg Nielsen, DTU Aqua


  • Professor Niels Lorenzen, DTU Aqua
  • Professor Monika Schmitz, Uppsala University, Sweden
  • CEO Ron Dirks, Future Genomics Technologies, The Netherlands

Chairperson at defence

  • Senior Researcher Manuel Gesto, DTU Aqua

The thesis

A copy of the PhD thesis “Reproductive Physiology of Female European Eel” may be obtained via e-mail. Please send your request to Rikke Hansen,

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