Abstract.— Inland culture of Liropenaeus vannarnei in low salinity well waters is currently conducted on a small scale in a few areas in the U.S. To successfully rear shrimp in low salinity water, postlarvae (PL) must be transferred from high‐salinity larval rearing systems to low‐salinity growout conditions. To determine effective transfer methods, a series of experiments were conducted under controlled conditions to evaluate the influence of PL age, rate of acclimation, and salinity endpoint on 48 h survival of shrimp. Three age classes of L. vannurnei PL (10, 15, and 20‐d) were acclimated from a salinity of 23 ppt to treatment endpoint salinities of 0, 1, 2, 4, 8, and 12 ppt. Survival of PL10 acclimated to 0, 1, or 2 ppt salinity was significantly lower than survival of PL acclimated to salinities of 4, 8, and 12 ppt. Survival of PL, and PL20 shrimp was only reduced for the 0 ppt salinity treatment, thus indicating a clear effect of age on salinity tolerance. The same age classes of PL were acclimated from 23 ppt to final salinity endpoints of I or 4 ppt at three different rates of salinity reduction: low, 19%/h; medium, 258/h, and high, 478/h. Survival was not significantly influenced by the acclimation rates for any of the three PL age classes. As in the fixed rate experiments, survival of the 10‐d‐old PL was significantly lower for shrimp acclimated to the 1 ppt endpoint compared to the 4 ppt endpoint. Under the reported conditions, age appears to influence PL tolerance to a salinity end‐point. A 10‐d‐old PL can be acclimated to 4 ppt with good survival, whereas 15‐ and 20‐d‐old PL can be acclimated to a salinity of 1 ppt with good survivals.

Two experiments (a) investigated the types of elaborations produced by fifth graders who varied according to academic successfulness, and (b) assessed the effects of different types of subject-generated elaborations on retention. The results of the first experiment indicated that the precision of students' self-generated elaborations had powerful effects on retention and that academically successful fifth graders spontaneously produced a greater number of precise elaborations than their less successful peers. The results of the second experiment indicated that less successful students who received appropriate training showed a large increase in the precision of their elaborations and in their performance on a memory test.

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