Dossier

Eels: population, management, migration, breeding and health

The European eel is an iconic and ecologically valuable species, but it is under pressure from overfishing, pollution and migration barriers. Together with public and private partners, Wageningen University & Research is developing sustainable solutions for the recovery of the eel stock - from breeding and migration to health and population management. By unravelling the complex reproductive cycle, we are working to conserve the species while strengthening the biodiversity and resilience of aquatic ecosystems.

The problems with the eel

The European eel is facing challenges such as overfishing, water pollution, habitat loss and obstacles in migration routes, which have led to a decline in its population. However, a great deal of progress has been made in improving population management, developing more effective fish passages and promoting eel migration. Research into eel reproduction and breeding is promising, with innovative approaches allowing better understanding and mimicking of the reproductive cycle. Efforts are also being made to improve eel health by addressing pollution and other risks. Investing in scientific eel research offers an opportunity to ensure the sustainable recovery of the population while also contributing to both ecological recovery and maintaining a future-proof fishing industry.

Eel population and management

The eel population in Europe is seriously endangered by several factors, including overfishing, pollution and migration barriers. Researchers are monitoring the population with fishing methods and data from fishermen. Management measures, such as fish passages and the stocking of glass eels, are being developed, but their effectiveness is still uncertain. WUR advises on management with attention to ecological protection and economic interests.

Read more in this longread about eel management:

“Ultimately, we all benefit from a healthy eel population”
03 June 2025 - Longread - Research into the state of the eel population is essential to determine how to manage it. However, it is not easy to manage a fish species which is distributed from Iceland to North Africa and which also migrates to the ocean to reproduce.

Eel migration

The European eel undergoes a complex migration between freshwater and salt water, its final destination being the Sargasso Sea. Barriers such as locks and pumping stations impede migration and increase mortality. WUR studies the migratory route and behaviour of the eel using advanced technologies such as transmitters and eDNA sensors to overcome migration barriers and protect the population.

Read more about in this longread about migration:

“We actually want to get inside the head of the eel”
15 May 2025 - Longread - The eel is a fascinating and mysterious but also endangered fish. Researchers are trying to learn more about the eel's spectacular migration. Their journey covering thousands of kilometres between freshwater and salt water has now become an obstacle course of dams, dykes and locks.

Reproduction and farmed eels

Researchers are trying to mimic the reproductive cycle of the European eel in the lab to relieve pressure on wild populations. Innovations such as freezing eel sperm for later use in reproduction and artificial organs are helping to advance research, but the transition from larva to glass eel is not yet possible in captivity. International cooperation is essential to improve breeding processes and for the sustainable recovery of the population.

Read more in this longread about breeding:

The holy grail of eel propagation
15 May 2025 - Longread - 'Closing the cycle': that's the big goal. If it would be possible to reproduce eels in captivity, the eel could be cultured and the pressure on the wild population alleviated. Researchers are getting closer step by step, but the step from larva to glass eel is still eluding them.

Eel health

Eel health is threatened by pollution in the water, such as dioxins, PFAS and drug residues. These substances can accumulate in adipose tissue and affect eel behaviour and reproduction. Researchers are studying how contaminants and diseases affect the eel population, and what measures are needed to keep the fish healthy.

Read more in this longread about health: