Surival of remote set seed of the clam Paphia malabarica : Effect of continued submergence and short term exposures to salinity variations

Abstract

Globally clam mariculture is a very popular aquaculture activity. The seed for farming to a great extent comes from the natural bed but in many countries the hatchery produced clam seed is farmed. Most farmers also have adopted the convenient technique of remote setting the seed. Remote setting is the technique of setting the pediveliger larvae produced in hatcheries at sites away from the hatchery usually near the farm site. Paphia malabarica commonly known as the yellow foot clam or textile clam is an important resource and supports a commercial fishery in their places of occurrence. In the present experiment pediveliger larvae of P. malabarica produced in the hatchery of CMFRI at Tuticorin were remote set at the Calicut Marine hatchery complex after a transit period of 26 hrs. They were reared in the hatchery and before transferring these clams to the field two sets of experiments mainly to (i) evaluate the effect of continued exposure to different salinities ranging from 0 to 35 ppt and (ii) evaluate 10,15,20, and 25 ppt and subsequent revival in ambient salinity of 35 ppt were conducted to understand their tolerance to variations in salinity.