Shrimp Physiology 



Zoula P. Zein-Eldin 



During the past year additional specimens of both white and brown 

 shrimp have been tested to determine oxygen requirements. They were se- 

 lected for sex and size and included two extremely large white shrimp a fe- 

 male of 51. 1 g. and a male of 42. 6 g. The brown shrimp were smaller but 

 included a large number of males to complete the picture of size and sex in 

 relation to oxygen consumption. 



Accurate records of molting in individual shrimp have been main- 

 tained. At least 4 animals have been held through 10 molts or more. Of these 

 individuals one male white shrimp was found to increase in carapace length 

 only 1 . 8 mm. (21 . 4 to 23. 2) in a 72-naonth period (13 molts) . In a second male 

 the carapace increased 3. 1 mm. (22. 5 to 25. 6) in a 52-month period (in which 

 the animal molted 11 times). More rapid gro'wth was recorded in two brown 

 shrimp. One female with an original carapace length of 25. 3 mm. increased 



1. 9 mm. in 4 months (6 molts), and a male with original carapace 19. 8 mm. 

 increased 3. 1 mm. in only 3 months. This latter animal also increased in 

 weight from 5.0 to 9.2 g. during 5 months in the laboratory. This group of 

 animals, held for a long period in the laboratory, was then retested to deter- 

 mine the oxygen consumption. In all cases there was a significant decrease 

 in oxygen consumption per gram (as much as 0. 1 ml. oxygen per gram per 

 hour). This was not entirely attributable to increase in size since the values 

 for the "held" animals were significantly lower than those for other animals 

 of the same sizes. 



Individual specimens of Trachyjjeneus similis and Squilla mantis 

 were also tested. Both of these animals used less oxygen than either the brown 

 or the white shrimp. The S. mantis tested used about half as much oxygen per 

 hour as a brown shrimp of similar size (1.4 ml. per hour for the 17 g. Squilla; 



2. 6 ml. per hour for the 20 g. P. aztecus). It is true that Squilla has more of 

 its body weight as exoskeleton than does the shrimp, but even after discounting 

 this, Squilla appears to metabolize more slowly. All data on both white and 

 brown shrimp are being analyzed in preparation for a final report. 



Nutritional studies have attempted to define mineral and vitamin 

 requirennents of two common species of shrimp. All experiments were car- 

 ried out in recirculating artificial sea water (see tables). The earliest ex- 

 periments indicated the importance of the calcium ion, for reduction of cal- 

 cium below 25 percent that of normal sea water caused test shrimp to die 

 within 30 hours. For this reason, the calcium concentration was increased 

 above that in normal sea water. 



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