Monitoring and advice on managing the eel population

Wageningen Marine Research researchers keep track of the effects of Dutch measures to control the eel populations. To this end, they monitor the occurrence, numbers and behaviour of eels in the Dutch lakes, rivers and ditches. They also monitor the size and age of eels extracted by fishers by sampling the market. These different samples form the basis for various (model) calculations to evaluate the eel population in the Netherlands.

  • Monitoring en advies voor aalstandbeheer

Decline in eel stock

The current European eel stock is only about ten per cent of what it was fifty years ago. In October 2020, the International Council for the Exploration of the Seas (ICES) warned that the situation of the eel remains critical and advised keeping deaths through human intervention to an absolute minimum.

A decline in living space due to an increase in the number of dykes, dams and water power stations is responsible for the plummeting eel population. In the Netherlands alone, some 15,000 obstacles hinder the eels' migration. Other factors include fisheries, parasites, climate change, pollution of surface water and predators.

International agreements

The eel is a prevalent species with an unusual life-cycle. All European eels spawn in the Sargasso sea, making the eel stock from North-Africa all the way to Norway one single population. Thus, eel management is an international affair.

To facilitate the recovery of the population, the European Commission has issued mandatory control measures is all member states. The Dutch eel management plan includes measures such as adjusting or removing physical barriers, restocking elvers, an obligation for sports fishers to return eel to the water and a closed season (from September to and including November) for eel fishing. Wageningen Marine Research is involved in the three-yearly evaluation of the eel management plan.

We offer

  • Long-term monitoring and datasets on the eel stock in the Netherlands and beyond, the influx of eels and elvers and migration of elvers and silver eels in Dutch waters.
  • Research on dioxin residues in eels
  • Contributions in advising ICES (WGEEL) on eel management in Europe
  • Three-yearly EU evaluation of the Dutch eel management plan
  • Population model IJsselmeer

Research on elver

All about eel stock and eel management

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