A new interesting paper has been accepted by the Journal of Applied Ecology entitled ‘Historical data to plan the recovery of the European eel‘. The authors are Miguel Clavero and Virgilio Hermoso who use historical sources to reconstruct the historical range of the European eel in the Iberian peninsula.
However the results are very relevant to eel management in Ireland where most of our eel habitats have been lost as a result of drainage works or fragmented by hydroelectric development. In Ireland traditional eel fishing has been banned, while hydroelectric operations continue without compromise.
Clavero & Hermo use baseline range information to set range targets for the recovery of the European eel in Iberia. This is a different approach to the abundance-based targets established by the European Union.
The results support the idea that the role of dams in the decline of the eel might have been underestimated
The European eel was historically widespread throughout the Iberian Peninsula, but it has lost over 80% of its original range, mainly due to river fragmentation by dams. The authors identified the dams that should be made passable for accomplishing specific range recovery targets, and show that acting upon 20 dams would make available 60% of the baseline eel range. The authors note that “even though several factors (e.g. overfishing, changes in oceanic circulation or parasites) may have a role in the decline of the eel, the spatial patterns in the local extinctions of the eel across the Iberian Peninsula are neatly linked to river fragmentation“. This is also the case for Ireland.
The socioeconomic importance of the eel and the consequent interest in its recovery can become an opportunity to address several of the environmental issues related to dams
The authors also note that “it must be taken into account that although the blockage of upstream migration is the most studied and most easily solved impact of dams, the impediment of downstream movement of the eel and other migratory fish is an equally important problem that must also be addressed“. They also add that “The recovery of the eel would not only restore an important socio-economic resource, but would also imply the recovery of a keystone species“.
Finally it is noted that “The socio-economic importance of the eel and the consequent interest in its recovery can become an opportunity to address several of the environmental issues related to dams“.
The abstract can be found here: