Where once the eel and the elephant were together: decline of the European eel because of changing hydrology in southwest Europe and northwest Africa?
Article first published online: 30 DEC 2010
© 2010 Blackwell Publishing Ltd
Fish and Fisheries
Volume 12, Issue 4, pages 380–411, December 2011
How to Cite
Kettle, A. J., Asbjørn Vøllestad, L. and Wibig, J. (2011), Where once the eel and the elephant were together: decline of the European eel because of changing hydrology in southwest Europe and northwest Africa?. Fish and Fisheries, 12: 380–411. doi: 10.1111/j.1467-2979.2010.00400.x
- Issue published online: 23 OCT 2011
- Article first published online: 30 DEC 2010
- Received 26 Apr 2010 Accepted 19 Nov 2010
- European eel;
- North Atlantic Oscillation
The collapse in recruitment of the European eel (Anguilla anguilla) since the early 1980s has been ascribed to possible overfishing, poisoning, parasitism, habitat loss and changes in ocean circulation. It is unclear which mechanism is most important, and firm data are lacking to make an assessment of the factors that apply over the full continental range. On the other hand, the recruitment of the American eel (A. rostrata) has declined along the western Atlantic at about the same time. This suggests a candidate mechanism that can affect both species together. A change in ocean climate may be a likely explanation, which is supported by a possible link between the North Atlantic Oscillation and one important recruitment index. However, it is unsafe to discard the other possible mechanisms because of lack of evidence. Habitat loss, in particular, may be important. We review over a century of evidence to suggest how the eel may have declined through progressive habitat loss that accelerated in the early 1980s as the result of economic development linked with hydrological changes. Although no single line of evidence can definitely prove one hypothesis for the eel decline, the total body of information may indicate a pronounced susceptibility in the southwest corner of the continental range closest to the Sargasso Sea that has been particularly affected by drought and dam construction. The sexual dimorphism of the species together with the energy requirements of the spawning migration may provide insight to explain the population collapse.