adverse effect. The two most useful 

 growth and reproductive rates (Table; 



cators of adverse effects were 

 5, and 6). 



Two experiments on bluegills were conducted, one started with young-of- 

 the-year fish exposed for 826 days, and one with adults exposed for 97 days 

 prior to spawning. At low H2S levels, the percentage increment in weight" 

 after short exposure was greater than controls (Table 4). After 826 days 

 exposure to 0.007 mg/1 H 2 S, the mean weight of the fish started as young- 

 of-the-year was approximately 63 percent of controls. In a second test, 

 after fish started as adults which were exposed for 97 days to levels of 



TABLE 4. INCREMENT IN WEIGHT AND SURVIVAL OF BLUEGILL STARTED AS 

 YOUNG-OF-THE-YEAR AND EXPOSED TO VARIED CONCENTRATIONS OF HYDROGEN 

 SULFIDE FOR 826 DAYS AT 2 OF 6.0 MG/LITER AND MEAN TEMPERATURE 

 OF 17.8-18.5 °C VARIED SEASONALLY--WEIGHT EXPRESSED AS MEAN 

 IN GRAMS AT SUCCEEDING INTERVALS 



Exposure 

 (Days) 



HgS Concentration (mg/1 iter ) 



56 

 392 

 826 



28 

 362 

 392 

 420 

 826 



TABLE 5. WEIGHT AMD REPRODUf )F ADULT BLUEGILLS EXPOSED TO VARIED 

 CONCENTRATIONS OF HYDROGf" IDE FOR 97 DAYS AT 23.5-23.9 °C 





