Assessing
the conservation challenges for the European eel through the Delphi technique
N.
Mukherjee, A. Clarhäll, H. Scharin, M. Svensson, A.H. McCarthy, J.W. Greenlee,
O. Alexa, D.A. Algera, M. Aprahamian, J.F. Asturiano, I. Ben Ammar, M.L.
Bianchini, E. Björkvik, J.D. Bolland, D.K. Cairns, B. Cédric, E. Ciccotti, I.
Domingos, C.K. Elvidge, S. Eyler, B. Geffroy, N.P. Griffiths, T.F. Grilo, S.
Januchowski-Hartley, D. Jellyman, E. Kärgenberg, R. Lagarde, R. Lyach, R.
MacNamara, P. Melià, P. Meulenbroek, V.
Nijman, P.A. Nilsson, C. Podda, P. Prouzet, M. Rohtla, N. Sjöberg, F.M.
Stein, R. Sühring, H. Svedäng, C. Tamario, T. van der Hammen, P. Verhelst, J.
Watz, M.S. Weltersbach, H. Westerberg, H. Wickström, J. Hugé
Abstract
The once abundant European eel (Anguilla
anguilla) is currently classified as a Critically Endangered species by the
International Union for Conservation of Nature. Although both the European
Union (through the 2007 Eel Regulation) and its member states have implemented
various conservation actions, many uncertainties remain regarding the actual
and anticipated effectiveness of these measures. This study aimed to identify
and prioritise the conservation and recovery measures for the European eel,
using the expert-based Delphi technique. We conducted a two- round Delphi
survey on eel conservation measures (these measures were derived from an
extensive review of the peer-reviewed literature). The findings highlight the
need for establishing a pan-European eel recruitment monitoring programme (to
obtain reliable eel population estimates), restoring access to suitable inland
habitats by removing migration barriers and improving habitat quality. Experts
also emphasized the necessity for a more stringent silver eel escapement target
and stronger enforcement of this target. While restocking of eel remains a
contentious issue, a set of preconditions could render it conditionally
acceptable. This study offers important insights into the areas of consensus
and divergence among eel experts in the challenging field of eel conservation.
We hope these results strengthen eel management decision-making such that this
Critically Endangered species does not become a museum specimen for future
generations.
Global
Ecology and Conservation 68: e04257. 2026
doi: 10.1016/j.gecco.2026.e04257