Abstracts (first author)
Dispersal and evolution of the European eel shaped by variations of North Atlantic drift currents
For open ocean broadcast spawners, environment-dependent dispersal is a crucial but critical life phase. The yearly recruitment fluctuations and cryptic adult population structure commonly observed in these species are assumed to reflect both the temporal and the spatial environmental conditions that early stages are exposed to. With a long-lasting ocean-dependent dispersal, the European eel (Anguilla anguilla) poses as perfect model organism to study the role of the environment in the evolutionary ecology of a broadcast spawner. To this end, we compared predictions made on dispersal, recruitment and population genetics by 45 years of high-resolution North Atlantic drift modeling with natural recruitment and population genetics at European coasts. We identify atmospherically-driven current variations in the Sargasso Sea as a key factor for a successful dispersal. We also demonstrate how unexpected findings of population structuring are consistent with contemporary recruitment levels, and with cryptic female philopatric behaviors within the Sargasso Sea. We suggest this strategy to be an evolutionary consequence of the unpredictable oceanic environment in the Sargasso Sea.