weight per day. Occasionally fresh shrimp meat was added. Feeding 

 was suspended 24 hours before testing and during the test period. 



Temperature Acclimation Procedure 



The temperature acclimation was carried on for the most part in 

 a specially constructed temperature-controlled filter system (Fig. 1) 

 in addition to thermostatically controlled Instant Ocean culture tanks 

 (Aquarium Systems, Inc) . The system consisted of four 250-gallon 

 (946 L) circular fiberglass tanks (#1-4 in the figure) connected in line 

 with a 250-gallon rectangular plywood tank (#5). The shrimp were held 

 in the circular tanks while the rectangular tank served for filtration 

 and for temperature control. Heating or cooling units were placed in 

 compartments A, B, or D as needed. Seawater was continuously pumped 

 from compartment D to the animal tanks through a polyvinyl chloride 

 (PVC) pipe (#15) fixed about six inches above the tanks. The water 

 in excess of a fixed level in the animal tanks drained through a 

 center standpipe (#6) . The drainage water flowed through a PVC pipe 

 below the tanks (#16) and was airlifted into compartment A. The 

 heavier particulate matter, especially sand, dropped out in compart- 

 ments A and B. Fine particulate matter was filtered out in compart- 

 ment C. The heated or cooled water was pumped into the animal tanks 

 from compartment D. Temperatures were successfully maintained to 

 within +].°C in this system. At 32°C about 150 shrimp were acclimated 

 in each of the four tanks but the number was increased to 200 at 18°C. 



Preparation of Salinity Media 



Raceway tanks received filtered water directly from Davis Bayou 

 adjacent to the Laboratory grounds. Salinities were adjusted to the 



Reference to trade names in this report does not imply endorsement 

 of the products. 



35 



