56 



Table 2. Internal signs of GBD in juvenile salmonids by 

 sample location. A total of 2,387 fish were sampled, 446 at 

 LGS, 417 at LMN, 585 at MCN, 483 at JDA, and 442 at BON. 

 Data aure in percent. 



External 



Internal 



Gill 



Internal Total 



Site Lateral Line Lateral Line Filaments Signs Affected 



^ Data are incomplete for JDA and BON. 



A total of 860 adult salmonids (459 in the Snake and 401 in the 

 Columbia) were examined between Hay 10 and June 20, with no 

 external signs observed. Eighty-one percent of the adults were 

 spring/ Slimmer chinook salmon. 



Invertebrates and non-salmonid fish were also sampled in the 

 river below Ice Harbor and Bonneville dams. Between May 10 and 

 June 16, 1,321 non-salmonids were sampled below Bonneville Dan 

 with no observed signs of GBD. Between these same dates, 3,467 

 non-salmonids were sampled below Ice Harbor Dam with 72 or 2.1% 

 exhibiting GBD signs. Over half of the organisms demonstrating 

 GBD signs below Ice Harbor Dam were observed diiring a period (May 

 11 through 18} when hourly dissolved gas levels, resulting from 

 involuntary spill, exceeded 130%. 



Physical monitoring data were calculated from data available from 

 the COE CROHMS reports. Table 3 presents period average TDG for 

 the monitoring sites most used in in-season management. Twelve 

 hour averages would be more meaningful since spill normally 

 occurred on a 12 hour per day basis. However, at this time those 

 data are availeQ>le only for the forebay monitors and monitors 

 below Bonneville Dam (see table 4) . 



Table 3. Total dissolved gas monitoring results from COS 

 monitoring locations. Data are in percent TDG and are 

 averages of hourly TDG readings between the dates noted. 



