0) 

 LJJ 



o 



d 



SALINITY (PPT.) 



Figure 29. — Qjg values for brine shrimp nauplii at five salinities. 



tigations based on different sources of cysts. 

 A careful examination of the physiological 

 characteristics of each population of brine 

 shrimp is warranted to determine if there is 

 indeed more than one physiological race of 

 brine shrimp. These experiments have demon- 

 strated that temperature and salinity signifi- 

 cantly affect the respiration rates of brine 

 shrimp nauplii from Great Salt Lake stock, 

 and that the Qjo's are affected significantly 

 only by temperature. 



EFFECT OF SUBLETHAL GAMMA 



IRRADIATION ON THE IRON METABOLISM 



OF THE PINFISH 



David W. Engel 



The iron metabolism of the blood and hema- 

 topoietic tissues of fish may be altered by a 



sublethal dose of gamma radiation. It has been 

 shown that a sublethal gamma radiation dose 

 of 2,000 rads caused significant reductions in 

 numbers of leucocytes and thrombocytes in 

 the blood of pinfish, but no reduction in ery- 

 throcyte numbers. The translocation of iron 

 59 through the blood and tissues of the pinfish 

 was not greatly affected. Investigations of the 

 effects of a graded series of radiation doses 

 on the cellular blood components of the gold- 

 fish, Carassius auratus , have shown that leu- 

 cocyte and possibly erythrocyte numbers were 

 reduced by radiation at these or lower levels. 

 The tench. Tinea vulgaris, also is sensitive; 

 1,500 rads caused anemia and depressed in- 

 corporation of iron 59 by the erythrocytes. 



The hematopoietic system of fishes, in con- 

 trast to that of mammals, has notbeen investi- 

 gated extensively. The metabolism of iron 59 

 by mammals is affected not only by radiation 



54 



