BEVACQUA D., ANDRELLO M., MELIA P., VINCENZI S., DE LEO G.A. & CRIVELLI A.J.
Identifying the factors influencing the settlement of European eel (Anguilla anguilla) juveniles in continental habitats is crucial to designing effective management and conservation measures for this endangered species.
A long-term data series (1993–2008) of European eel and European catfish (Silurus glanis) abundance in a freshwater canal of the Camargue water system (southern France), along with parallel data on water salinity and glass eel abundance in the adjacent Vaccare`s lagoon, was analysed to identify the possible causes of decline el abundance observed in the canal during the last two decades. A model including glass eel recruitment and catfish abundance as covariates explained 78% of the observed variation in eel settlement success.
Results suggest that (1) salinity does not play a significant role in determining the fraction of eels moving from the brackish lagoon to the canal; (2) density dependence affects settlement success, possibly through a reduction of juvenile survival in the adjacent lagoon; and (3) catfish abundance is negatively correlated with eel settlement. We discuss this latter point in terms of possible predation of catfish upon eels and/or inter-specific competition between the two species.
Full bibliographical reference:
BEVACQUA D., ANDRELLO M., MELIA P., VINCENZI S., DE LEO G.A. & CRIVELLI A.J., 2011. Density-dependent and inter-specific interactions affecting European eel settlement in freshwater habitats. Hydrobiologia 671 p259-265