Reproductive studies on the short neck clam Paphia malabarica (Chemnitz) from Dharmadom Estuary, Kerala, India

Abstract

Maturation and spawning of the short neck clam Paphia malabarica was studied from Dharmadom Estuary, in northern Kerala, India. The breeding season was from October to February, with peak spawning in November and December. Sexual activity commenced from March onwards and lasted till September. The peak somatic period was from February to April when more numbers of indeterminates appeared in the population. There was not much difference in the size at maturity (Lm) for females and males; Lm was estimated to be 20 mm for females and 22 mm for males. Chi-square test indicated that the sex ratio differed signifi cantly (p<0.01) from the theoretical 1:1 ratio, only in the month of May. The abundance of mature clams showed positive correlation with salinity and negative correlation with temperature.