Abstract
Abstract: Selective behaviors in salinity variations of Corbicula japonica larvae were experimentally studied with vertical salinity gradients in glass cylinders. Experiments were conducted in dark and illuminated conditions at 7 stages(16, 25, 47, 68, 141, 213 and 309 hours after fertilization). Larvae were active in selecting specific ranges of salinity that changed along developmental stages. Early straight-hinge larvae(25 and 47 hours after fertilization)selected high salinities(15.21-19.21psu on average)while late straight-hinge larvae(68 hours after fertilization)selected moderate salinities(13.45-14.29psu). Postlarvae(141 and 213 hours after fertilization)selected low salinities(6.44-11.38psu). When downward illuminations were given from the water surface, larval aggregations were formed in higher layers than in dark conditions. At 309 hours after fertilization, postlarvae did not form clear aggregation, and some individuals were found settling on the bottom.
