Ex perimental Growth Studies With Postlarval Brown Shrimp 



Zoula P. Zein-Eldin 



Studies of shrimp growth rate as an index of the suitability of sim- 

 ulated environmental conditions were begun this year. In the first series of 

 experiments to determine a practical diet capable of supporting growth in the 

 laboratory, we compared the growth and survival of postlarval brown shrimp 

 fed various foods. These diets included: live brine shrimp (nauplii); brine 

 shrimp plus a species of filamentous brown alga; the brown alga alone; ground 

 mullet; ground shrimp; and a species of filamentous blue-green alga. Salinity 

 in test aquaria was maintained at ZSfoo with room temperature ranging from 

 23° to 27° C. The experiment began with 150 postlarvae per aquarium. At 

 intervals of 5 to 7 days, 10 shrimp were removed from each test aquarium, 

 weighed, their length naeasured, and preserved. The mean weight of shrimp 

 in each test group is indicated in the accompanying figure. Data for both 



100- 



S I 50-1 



DIET 



— Brine Shrimp 



■ — Ground MuUet (or Shrimp) 



— Blue-Green Algo 



— Brown Alga 



Laboratory growth of postlarval 

 brown shrimp fed various diets. 

 (Salinity: 25%c) 



diets containing brine shrimp were combined, since the addition of the brown 

 alga increased neither the growth nor the survival rate but merely afforded 

 a hiding place during periods of molt. Growth data from the groups fed 

 ground nnullet and ground shrimp were similarly combined. 



It is quite apparent that a diet of live brine shrimp, yielding a mean 

 growth of 2. 8 mg. per day and a maximum rate of 7. 8 mg. per day, gave far 

 better results than any of the other diets. Neither of the algal diets produced 

 good growth, and, in addition, the rate of survival for animals fed the brown 

 alga alone was less than half that of the animals fed brine shrimp (33 percent 

 as against 80 percent). The ground-meat diets tended to foul the experimental 

 aquaria, making them impractical food items. It was concluded that live- 

 animal foods are by far the most satisfactory, not only in terms of growth 



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