SPECIAL REPORTS 

 Sea-Water System 



Kenneth T. Marvin and Ray S. W-heeler 



The recirculating sea-water laboratory completed in January 1961 

 provides excellent space and facilities for holding large quantities of shrimp 

 and fish, enabling us to undertake studies which should add measurably to our 

 knowledge of these organisms. Studies now under way include the determina- 

 tion through bioassays of the effects of toxicant materials on marine organ- 

 isms, the spawning and rearing of larval shrimp to aid in the identification of 

 different species, and the testing of stains for marking shrimp to determine 

 their growth, mortality, and migration routes. As space permits, the sys- 

 tem's facilities will be available for research on marine problems by other 

 than Bureau investigators, e.g.. The Marine Laboratory of the A. and M. 

 College of Texas is using it in experiments on oyster nutrition. 



Sea water is brought to the system in a 4, 000 gallon stainless steel 

 water truck, run through the filter beds, and pumped into two 28, 000- gallon 

 redw^ood tanks. Water flows by gravity from either or both 28, 000- gallon 

 tanks to the laboratory through a 4- inch polyvinylchloride pipe. After entering 

 the laboratory, the pipe branches into 3- inch ceiling pipes that supply water 

 to the three laboratory tank rooms. Petcocks in the ceiling pipes conduct the 

 water into the holding and experimental tanks. From the tanks water flows 

 into concrete return troughs connected to the filter. Water from the tanks can 

 also be directed into other troughs connected to a drain to facilitate cleaning. 

 The two filter beds are similar in design to those of mixnicipal water treat- 

 ment plants and consist of washed (river) sand on a bed of graded gravel. The 

 gravel overlays a network of small perforated polyvinylchloride pipes leading 

 into a 4- inch pipe that discharges into a 9, 000- gallon concrete sump located 



The two filter 



beds which lie 



on top of a 



9, 000- gallon 



sump. 



68 



