INTRASEASONAL CHARACTERIZATION OF GLASS EEL MIGRATION IN THE RIVER TIBER - SPACE AND TIME DYNAMICS

Glass eel (Anguilla anguilla) upstream migration was studied in the Ri ver Tiber estuary to obtain a better understanding of spatial and temp oral migration dynamics within the season of ascent. Using data from g lass eel fisheries, time series analysis of daily catches per unit of effort revealed a fortnightly cycle that can be related to invasion wa ves possibly corresponding to tidal currents. The amplitude of these w aves appeared to correspond to the tidal area of the estuary. Furtherm ore, glass eels apparently had a delay in this area before resuming up stream migration. (C) 1995 The Fisheries Society of the British Isles