Diurnal Activities and Tidal Migrations of the Brackish Water Prawn Palaemonetes Varians (Leach) (Decapoda, Caridea)

DIURNAL ACTIVITIES AND TIDAL MIGRATIONS OF THE BRACKISH WATER PRAWN PALAEMONETES VARIANS (LEACH) (DECAPODA, CARIDEA) BY L. J. ANTHEUNISSE, J. J. LAMMENS and N. P. VAN DEN HOVEN Department of Zoology, Free University, Amsterdam, the Netherlands INTRODUCTION The palaemonid prawn Palaemonetes varians (Leach) inhabits several types of brackish waters near the western coasts of Europe, viz. estuarine areas, tidal salt- marsh creeks, brackish inland ditches, and pools near the coast. Within a brackish environment, Palaemonete.r species, including P. varians, show a clear preference for dead waters and those with low current velocities (e.g., Dahl, 1948; Holthuis, 1950; Dobkin, 1963; Jefferies,