Consequences of adaptive plasticity and local adaptation in the European eel: assessing population-level responses to anthropogenic pressures

• Main Authors: Mateo, M., Lambert, P., Tétard, S., Drouineau, H.
• Other Authors: IRSTEA BORDEAUX UR EABX FRA, EDF HYNES CHATOU FRA
• Format: Other/Unknown Material
• Language: English
• Published: 2015
• Subjects: ANGUILLA ANGUILLA; ADAPTATION AU MILIEU; PERTURBATION ANTHROPIQUE; adaptation to environment; anthropogenic disturbance; Norway; Anguilla anguilla; European eel
• Online Access: https://irsteadoc.irstea.fr/cemoa/PUB00051541

As a result of a collapse observed since the 80's, the European eel (Anguilla anguilla) is now classified as critically endangered in the IUCN Red List and the European Commission enforced a European Regulation which requires a reduction in all sources of anthropogenic mortality. The strong spatial heterogeneity of anthropogenic pressures affecting eel population in Europe combined with a spatial variability in life history traits at both the distribution area and river catchment scales raise specific challenges for management. This catadromous species represents a panmictic population that spawns in the Sargasso Sea and whose larvae are passively transported by ocean currents to the inner waters of Morocco to Norway. These features promote the emergence of phenotypic plasticity rather than local genetic adaptation as an adaptive response to spatially structured environment and suggest that life history traits heterogeneity may be a result of this adaptation. The first version of the evolutionary ecology-based model for eel (EvEel) explores spatial variability in terms of life history traits, tactics and demographic attributes as a result of adaptive phenotypic plasticity. Assuming fitness maximization, the model was able to reproduce most patterns observed across river catchment scale and distribution area. This suggests that sex determination, length-at-silvering and habitat use may be plastic mechanisms that allow eels to cope with environment variability. A second version of the model is currently being developed to take into account genetic variability in addition to phenotypic plasticity. A preliminary exploration of the model is exploring if the combination of both aspects improves the performance of the model and its ability to mimic observed patterns. Then, the model will be used to assess the impacts of anthropogenic pressures (habitat fragmentation, pollution or fishing) in terms of fertile biomass and population's demographic attributes. After this theoretical step, model calibration and validation will be applied to a real case of study, such as the Garonne-Dordogne catchment. Finally, this model could serve as a decision-support tool to aid the management of the uncertain environment.