Selective tidal stream transport in silver European eel (Anguilla anguilla L.)--Migration behaviour in a dynamic estuary

Different fish species use selective tidal stream transport (STST) to efficiently migrate through strong tidal systems to complete their life cycle, but the use of STST by silver European eels (Anguilla anguilla L.) is still controversial. In this study, we found strong evidence that silver European eels apply STST. The results illustrate that eels can distinguish between ebb and flood and suggest that tides play a role in orientation, either directly or indirectly. The general migration speed was higher in the downstream part of the estuary compared to the upstream part, while tidal migration speed was equal in both parts, indicating that eels migrated more consistently in the downstream part. The results of this study give insight in how a diadromous species migrates through an estuary and underline the importance of the tides.