GROWTH AND BREEDING HABITS OF THE CLAM, KATELYSIA OPIMA IN THE KALBADEVI ESTUARY AT RATNAGIRI

Abstract

The study of growth in Katelysla opima has been attempted by lengthfrequency
method which showed that this clam grows to a size of 22 mm,
31 mm and 43 mm by the end of its first, second and third year of life.
Length-height and length-breadth relationships were seen to be of the linear type.
The relation between length and weight followed Cube law. Katelysia attains
sexual maturity at the size of 12 mm in males and 13 mm in females, and
spawns after one year old. Two spawning seasons, a major in October and
a minor in April, have been observed. The growth rate is not uniform throughout
the year. There is a period of rapid growth from September to January, of
moderate growth from February to May and poor growth from June to September.
Low salinity (during monsoon season) appears to have influence,
resulting in retardation of growth. Certain disturbance-rings, on account of
arrested growth during monsoon, have also been used for confirming the age
of the clams.