Alternative flood tide transport tactics in catadromous species: Anguilla anguilla, Liza ramada and Platichthys flesus

Abstract : Flood Tide Transport (FTT) was investigated using experimental annular flumes and analysed by Maximum Entropy Spectral Analysis (MESA) to compare 3 species which use FTT: thinlip mullet Liza ramada, European eel Anguilla anguilla and European flounder Platichthys flesus. Juvenile fishes were submitted to experimental conditions simulating estuarine conditions in order to induce a behavioural rhythm which can be deemed comparable to FTT. MESA highlighted several behavioural rhythms within the same time series. The three species exhibited tidal rhythms in relation to time of day of migration, social behaviour and behaviour during ebb-tides. We hypothesise that ecological and morphological traits could induce these behaviours and indicate that it is possible to predict FTT variations for all catadromous species using diet ecology and morphology.