Figure 41, — Feeding brown shrimp during illumination experiment. 



animals grew from 18 to 38 mm. (0.71-1.50 

 in.), food consumption of the four shrimp, 

 A, B, C, and D, respective'.y, was 5,400, 5,700, 

 6,400, and 6,100 brine shrimp per day; rate 

 of growth was .04, .04, .04, and .05 in. per 

 day; and feeding efficiency was 43, 43, 34, 

 and 45 percent. This variability in efficiency 

 may contribute to the wide variation in growth 

 of our experimental animals. More work of 

 this type is in progress. 



Attempts in the laboratory to induce growth 

 in shrimp 2 in. or more in length have gen- 

 erally been unsuccessful. Brine shrimp larvae 

 are excellent food for postlarval shrimp, but 

 this diet is impractical for larger shrimp 

 because of the extremely large number of 

 larvae required to feed each animal. In view 

 of this problem, a study was made to find a 

 diet that would support growth in juvenile 

 and subadult shrimp under laboratory condi- 

 tions. In an experiment, individual subadult 

 white shrimp were isolated in 1- and 15-gal. 

 aquaria. Three diets were tested--canned 

 liver (commercial cat food); canned, minced 

 clams; and frozen, mature brine shrimp. 

 Mortality in the small aquaria was high (77 

 percent) probably because of bacterial fouling 



which seemed less in the larger tanks. Growth 

 in the group fed liver and the group fed clam 

 was actually negative in some animals; weight 

 decreased as much as 0.5 g. (.018 oz.) in 28 

 days. Very slight weight increases, averaging 

 about 0.6 g. (.021 oz.) in 28 days, occurred 

 in shrimp fed frozen brine shrimp. We are 

 continuing this study and are evaluating other 

 diets. 



Several short-term experiments with 

 juvenile and subadult white shrimp (62-132 mm. 

 or 2.4-5.2 in.) were carried out to test sur- 

 vival under various combinations of tem- 

 perature and salinity. Test animals were 

 isolated in compartmented containers and 

 held at test conditions for 24 hr. At the end 

 of this period, we noted the survival. At the 

 midrange of both temperature (25° C. or 77° 

 F.) and salinity (25 p.p.t.) survival was good. 

 Poor survival was evident below 12.5'-' C. (55° 

 F.) and 13 p.p.t. and also above 320C. (88° F.) 

 and below 10 p.p.t. salinity. At high salinity 

 (40 p.p.t.) survival was varied (0-100 percent) 

 at both 25° C. (77° F.) and 35° C, (95° F.), 

 indicating that these are marginal conditions 

 (fig. 43). We plan further tests to obtain in- 

 formation at various levels of temperature and 



44 



