Life Cycle and Population Dynamics of the Polychaete Perinereis cultrifera from the Algerian Mediterranean Coast

Abstract. The polychaete Perinereis cultrifera ( Grube, 1840 ) (Nereididae) is common along Algerian coasts in algal‐covered hard bottoms. An intensive study was conducted from June 2000 to June 2001 to characterise the life cycle of an intertidal and upper subtidal population of P. cultrifera in Algeria near the Tunisian border (30 km). P. cultrifera has a 3‐year life span and reproduces exclusively by epitoky. The reproductive season is short, and spawning occurs in late April/early May when the sea‐water surface temperature starts rising. Female sexual differentiation starts in February in the second year of life; thus, the oocytes take 16 months to mature and their diameter at maturity is approximately 250 μm.