Diel and seasonal movements of the critically endangered European eel

Sammendrag

The critically endangered European eel is declining throughout its range and more information on which to base management plans is necessary. Here we present data collected by electrofishing and PIT telemetry on the habitat use and movements of eel in an English chalk stream in Dorset, southern UK. Eel were sampled quarterly for three years and movements between the main river and a side stream monitored by an in situ PIT detector. Eel abundance was highest in the side stream during summer and autumn and movement between the main river and side stream was greatest during spring, summer and autumn. Eel demonstrated nocturnal movements in/out of the side stream during spring and summer, however this diel pattern was not evident in autumn. The study demonstrates continual use of the connected floodplain by eel, underlining the importance of lateral connectivity to floodplain habitats to the species. Connectivity can be modified or lost by a number of anthropogenic activities such as hydropower and road culverts, but in many cases these can be avoided by proper and sound management. Key words: behaviour, Anguilla anguilla, movement, river connectivity, floodplain.