Annual reproductive cycle of the wedge clam, Donax cuneatus Linnaeus

Abstract

The venerid clam Venus mercenaria of the temperate waters is known to have a distinct annual reproductive cycle, gametogenesis taking place during the autumn and winter and spawning between July and September (Loosanoff, 1937). Studies on the reproductive activity of the economically important clams of the family veneridae of the Indian coasts have received some attention. Hornell (1922) has observed that in Meretrix casta spawning takes place twice a year, during April- May and September on the east coast. Abraham (1953) and Durve (1964) have found that M. casta in the Adyar estuary and Mandapam fish farms spawn several times a year. In the estuarine clam, Katelsia opima, Rao (1951) has observed that gametogenesis takes place between April and August and' that spawning which commences in December is completed in January. The reproductive periodicity of the clams of the family Donacidae which occur in fair abundance along the Indian coasts has not been studied in detail except for the observations of Nayar (1955) who has stated that Donax cuneatus of the Palk Bay spawns between January and April and of Alagarswamy (1967) who very recently reported prolonged spawning from November to June in D. faba from Mandapam coast. The annual reproductive cycle of D. cuneatus of the Madras coast has been studied in the present work based on the seasonal gonadal changes of the adult clams.