THE FRESH-WATER SHRIMP PARATYA-AUSTRALIENSIS (KEMP, 1917) (DECAPODA, ATYIDAE) IN ESTUARIES OF SOUTH-WESTERN VICTORIA, AUSTRALIA

All life-cycle stages of Paratya australiensis, formerly thought to oc cur predominantly in freshwater environments, were found to be common in estuaries of western Victoria. Highest densities of larvae were fou nd below the halocline in stable, open, well developed, salt-wedge est uaries. Larvae developed in the salt wedge, and juveniles recruited to littoral weed beds. Adults were most abundant in low salinities among submerged, leafy macrophytes. Although recruitment to estuaries permi ts the avoidance of fatal drift of larvae to sea, tolerance of saline conditions may permit rare dispersal of larvae between estuaries. A ne w model for the biogeography of Paratya is proposed.