Tolerance of Young Fish of Large Yellow Croaker (Larimichthys crocea) to Low Salinity

Tolerance of young fish of large yellow croaker,Larimichthys crocea,under different low salinity conditions were studied by performing experiments of acute and gradient salinity changing.The young large yellow croaker had low lethality rates within the first 72 h after they were transferred directly from sea water(salinity of 27.2) to water with salinity from 3 to 24.A survival rate of 72% was calculated within the first 72 h after they were transferred directly from sea water to water with salinity of 2.The deaths began at 3 h after transfer and the majority of the fish had died within 24 h after they were transferred directly from sea water to water with salinity of 1;afterwards all of the fish had died within 6 h after they were transferred directly from sea water to fresh water.While the young fish of large yellow croaker were transferred directly from sea water to water with salinity of 6 and after then the water salinity declined with different speeds,their mortality had no significant difference with the results in the experiments of acute salinity changing when the water salinity was higher than 3,and their mortality was lower than that of the experiments of acute salinity changing when the water salinity was below 2.The results showed that in fact young fish of large yellow croaker are able to tolerant certain level of low salinity stress.