Experimental studies on the hatching rhythm and larval release in Palaemonid and Atyid prawns

Abstract

Abstract. The hatching behaviour and larval release of Macrobrachium lanchesteri (de Man) (Palaemonidae) and Caridina weberi (de Man) (Atyidae) are described in relation to natural (LD nat) and altered laboratory (LL, DD and DL) illumination cycles. A clear nocturnal hatching rhythm is observed in female Macrobrachium lanchesteri, which releases the larvae in batches on successive nights till all the eggs held in the brood are hatched. Maximum number of larvae are released between 24 and 3 h. In Caridina weberi such a precise rhythm is loosely operative.