between species of commercial shrimp. We 

 chose to investigate the use of paper chro- 

 matography of the free amino acids. These 

 compounds, the building blocks of body tissue, 

 are found free in the tissue fluid and can be 

 extracted with alcohol. Individual amino acids 

 in the extract are identified by color reactions 

 with certain chemicals and by the distance they 

 move in certain solvents. If some amino acids 

 were present in one species but not in the 

 others, these compounds could be used to 

 identify the species of shrimp. 



We examined extracts of the tail muscle of 

 brown, white, and pink shrimp. The patterns 

 of the free amino acids showed no significant 

 differences between the species. Furthermore, 

 the amino-acid pattern of individuals within a 

 species did not change within a size range of 

 12 to 150 mm. All three species had very 

 large amounts of free amino acids. 



Zoula P. Zein-Eldin, Project Leader 



GROWTH AND SURVIVAL 



Experiments during the past year tested the 

 effects both of temperature and of container 

 size on growth of postlarval shrimp. Experi- 

 ments were made also with three species of 

 laboratory-hatched postlarvae. 



Postlarval white shrimp were collected from 

 the surf. These animals were held at nine 

 temperatures from 15° to 35° C. at 2.5° C 

 intervals for 28 days to observe the effect on 

 growth. Growth in white shrimp generally 

 increased as temperature increased, except 

 at the upper extreme (fig. 34). At the highest 

 temperature (35° C.) growth rate was de- 

 pressed. The animals were larger at tempera- 

 tures between 25° and 32.5° C. Survival at all 

 temperatures except the two extremes was 70 

 percent or better. 



A comparison of survival of brown and 

 white shrimp is shown in figure 35. At low 

 temperature (15° C.) brown shrimp survived 

 better than white shrimp. From 17.5° C. to 

 about 25° C, survival of the two was similar. 

 Above 25° C. white shrimp survived much 

 better than brown shrimp. These data seem 

 logical in view of the natural seasonal habits 

 of postlarval shrimp. Brown shrimp postlarvae 

 ordinarily arrive in the estuaries muchearlier 

 in the year than those of white shrimp. Con- 

 sequently, the brown shrimp are normally 

 subjected to much cooler water. 



In past growth experiments we have found a 

 wide final size range of animals in a given 

 aquarium. We do not know if this variation 

 was caused by crowding, container size, food. 



500 1 



GT 2 



30° C (78) 



100- 



^ 32 5»(92l 

 ,' 25° (78) 

 ■^ 275'' (85) 



-I- 

 15 20 



TIME (DAY'S) 



Figure 34.— Mean increase in weight of white shrimp 

 postlarvae exposed to different temperatures (C.) for 

 1 month. Figures In parentheses Indicate percentage 

 survival. 



25" 



TEMPERATURE l"C.) 



Figure 35. — Percentage survival of postlarval brown 

 shrimp (series 1 and 2) and postlarval white shrimp 

 (GT-2) held at various temperatures for 1 month. 



32 



