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The Adequacy of Biological Monitoring 



Monitoring for visible signs of gas bubble disease is unlikely to provide adequate 

 protection for salmon. By the time gas bubble disease is widely apparent in either the 

 juvenile or adult populations, it is likely substantial losses will have occurred. During the 

 serious dissolved gas problems in the 1960s and 1970s, it was uncommon for large numbers 

 of migrants to be observed with gas bubble disease symptoms. 



Why NMFS Can Achieve 80% FPE Without the Risk of Elevated TDG 



NMFS' plan is designed to achieve 80% "Fish Passage Efficiency" or FPE, which is 

 a measure of how many fish pass by a dam by means other than turbines. It is not a 

 measure of how many fish pass the dam alive. For example, with 80% FPE, 20% of the 

 fish would go through the turbines; assuming 10% turbine mortality and zero bypass or spill 

 mortality, 2% of the fish would die, and 98% of the fish would pass the dam alive. When a 

 significant portion of the fish are transported around the dam, the percentage of fish 

 surviving passage around a particular project is even higher. If half the fish are transported, 

 then 99% will pass the project alive (assuming insignificant barging mortality). 



In the biological opinion, NMFS presents its estimates of the amount of spill required 

 to achieve 80% FPE. NMFS does not present the bases of its calculations. To understand 

 how the amount should be calculated, it is necessary to understand the concept of "Fish 

 Guidance Efficiency" or FQE. Many of the projects have bypass systems to divert juvenile 

 salmon away from the turbines, which generally consist of moving or "traveling" screens. 

 By placing fyke nets behind these traveling screens and testing how many fish get past them, 

 fishery agencies calculate the percentage of fish guided away from the turbines, or FGE. 



Thus at projects with bypass systems (Lower Granite, Little Goose, Lower 

 Monumental, McNary, John Day and Bonneville), to reach a given level of FPE, one must 

 merely know the FGE, and then spill until the proportion of juveniles passing over the 

 spillway reaches the desired level. For example, if FGE is 50%, and the target FPE is 80%, 

 the amount of spill required to reach 80% FPE is the amount of spill that passes 30% of the 

 juveniles over the spillway. 



I have recently re-examined the latest data on fish guidance efficiency (FGE) of the 

 traveling screen-bypass systems and some reports on fish passage behavior during periods of 

 spill. I am convinced that the 80% FPE can be achieved at all the dams with bypass systems 

 without exceeding 115 percent TDG in the spillway tailrace. 



NMFS appears to assume that the number of fish passing by way of the spill is 

 directly proportional to the volume of water being spilled. Several studies indicate that this 

 is most likely not correct (Faurot et al. (1982), Stuehrenberg et al. (1986), and Giorgi gt al. 

 (1988)). In these studies, the effect of spill on juvenile spring chinook and steelhead 

 behavior was examined at Lower Granite and John Day Dams. All indicated that 

 significantly more fish pass via the spillway than the 1:1 ratio apparently assumed by NMFS. 



