Table 4. --Summary of mortality data on simultaneous staining and 

 control experiments 



Percent Percent Total 



No. of Method Total mortality mortality mortality 



Stain shrimp Imm . F. Inj . days A B in percent 



Remarks- 



Control 



Fast Green 



FCF 20 



20 



20 



XX 



84 



15 



10 80 11 undetermined; 



Menzel's solution. 



XX 



84 



25 



35 90 6 undetermined; 



1 percent Harleco, 

 SW. 



84 



10 



75 



12 undetermined. 



Trypan 

 Blue 



Niagara SKy 

 Blue 6B 



Control 



30 



30 



30 



XX 



52 



47 



XX 52 



47 



23 



52 



53 



9 undetermined; 

 77 1 percent Nat'l. 

 Aniline; 10%DW, 

 90%SW. 



83 



5 undetermined; 1- 

 percent solution; 

 10%DW, 90%SW. 



8 undetermined. 



Trypan 



Red 60 



Control 



60 



XX 



58 



28 



16 undetermined; 

 28 83 2 percent Nat'l. 



Aniline in DW. 



58 



23 



10 



77 



26 undetermined. 



1/ DW = Distilled water; SW= Sea water. 



both have proved relatively fast and can be dis- 

 tinguished for more than 120 days, the National 

 Aniline stain results in a much more vivid 

 coloration. 



Niagara Sky Blue 63 produced distinctive 

 abnormal coloration when injected in a 1 -per- 

 cent solution prepared with sea water and a 

 small quantity of distilled water. The resultant 

 blue branchial concentration is fast for more 

 than 100 days. With this stain, the injection 

 quantity is critical, and if injection volumes ex- 

 ceed 0.03 cc . with medium shrimp initial 

 mortality may be high . Initial mortality excepted, 

 available data indicate no significant mortality 

 increase over that of uninjected shrimp. 



Injection of Trypan Blue, either National 

 Aniline or Harleco, results in distinctive blue 

 branchial coloring which is easily identifiable 

 over a period of at least 220 days. 



Immediate coloration ranges from a 

 general pale -blue tint to a slight bluish staining 

 of the branchiae. Gradual branchial concentra- 

 tion results in a dark -blue staining of these 

 structures within 48 hours . Subsequently the 

 branchiae may attain a bluish -gray coloration, 

 but this change is slight and does not serve to 

 complicate the differentiation of stained and 

 normal shrimp. Owing to the inconspicuous 

 nature of the initial coloring there is a definite 

 tendency to overinject with this stain. Excessive 

 injection volumes result in high initial mortality, 

 and experience has shown that injections should 

 not exceed 0.04 cc. of a 1 -percent solution with 

 medium shrimp. 



Racek (1955) abandoned Trypan Blue in- 

 jections owing to excessive mortality. With the 

 exception of high mortality in one test following 

 overinjection, no excessive mortality was ascribed 

 to Trypan Blue in the present study. In a 52 -day 



21 



