Figure 40. --Examining a chromatogram of extracts from the tail muscle of 

 various shrimp species. 



hope that a chemical method of identification 

 may be developed. Such a method would be 

 useful in identifying species of postlarvae 

 during stages when there are few anatomical 

 differences. The technique of paper chromatog- 

 raphy (fig. 40) is being used now. Preliminary 

 results suggest that only quantitative differ- 

 ences may exist between the amino-acid com- 

 positions of the two species. 



Zoula P. Zein-Eldin, Project Leader 



GROWTH AND SURVIVAL OF SHRIMP 



Experiments during the past year were de- 

 signed to determine the influence of various 

 factors on growth of white and brown shrimp. 



Since most of our previous laboratory- 

 controlled growth experiments were illumi- 

 nated, we thought it necessary to determine 

 what effect, if any, various light regimes 

 have on the growth of postlarval shrimp. We 

 tested three conditions--constant illumination, 

 constant darkness, and intermittent light and 

 dark (12 hr. light and 12 hr. dark). Animals 

 were kept at 25° C. (77° F.) and brine shrimp 



larvae supplied as food (fig. 41). Growth for 

 both white and brown shrimp was good, about 

 0.7 mm, (.03 m.) per day for each species 

 at the various conditions. No significant dif- 

 ference was seen between the three experi- 

 mental groups. Thus light, as used in past 

 experiments, has no effect on growth of 

 postlarval brown and white shrimp. 



Data, from past experiments reveal that 

 after a period of growth in the laboratory 

 the range of sizes is frequently wide within 

 a group of test animals. We do not know 

 whether this difference in size is related 

 to food consumption of the individual shrimp 

 or to some other factor. 



In an attempt to determine the cause of this 

 disparity in growth, we made one experiment 

 to confirm or eliminate food consumption as 

 the controlling factor. In this experiment, four 

 postlarval brown shrimp were isolated in 

 1-1. (0,9 qt.) containers, one per container. 

 We kept individual records of daily growth 

 and food consumption. Sampling just prior 

 to and after feeding every 24 hr, gave an 

 estimate of the number of brine shrimp con- 

 sumed daily (fig, 42), During the time the 



43 



