Surface activity,zonation and migrations of Talitrus saltator on a Mediterranean beach

The present study considers a population of Talitrus saltator (Montagu, 1808) living along a Mediterranean beach (Burano, Grosseto, Italy). From April 1986 to March 1987 the annual and daily patterns of amphipod activity were analysed together with zonation and the direction and extent of movements. An annual bimodal activity pattern was established with a first peak of activity in late spring and another one in autumn. Daily activity was predominantly nocturanl with two peaks, one of which could be suppressed or depressed in accordance with particular climatic conditions. The species studied was generally limited to the eu- and supralittoral part of the beach, but the extent of zonation could vary according to climate. Differences between juveniles and adults appeared both for activity patterns and for zonation. Movements were predominantly (ca. 85%) along the sea/land axis with a landward migration always followed by seaward one. Under conditions of high relative humidity and rain, the migrations towards land could extend to the dune. Movements parallel to the shoreline were demonstrated in a separate experiment (in June and October 1987 and June 1988) using the capture-mark-recapture method. The maximum distance covered registered in one night was 200 m.