116 



days. A bargeload of fish being transported fi^m the Snake River (approximately 0.6 

 million) was released above iJie project and passed in spill with high levels of dis- 

 solved nitrogen. Juvenile monitoring at The Dalles Dam immediately began detect- 

 ing signs of GBT in fish with anywhere from 7 to 33 percent of salmonid species 

 aifected within two (Lays. Bonneville Dam monitoring indicated that approximately 

 74 percent of the steelhead sampled 4 days later exhibited visual signs of GBT. The 

 second instance was in 1993 over the Memorial Day weekend. Power demands were 

 extremely low and 100 percent of nighttime flow was spilled at Little Goose Dam. 

 Dissolved gas levels in the forebay of Lower Monumental Dam (the next down- 

 stream project) were measured in excess of 130 percent. Subsequent to this high 

 spill operation approximately 19 percent of fish at Lower Moniunental Dam exhib- 

 ited signs of GBT. Since these incidents our methods of detecting the early signs 

 of GBT have improved with specific areas of fish being observed for GBT, extensive 

 training and the use of magnification. 



3. Are there risks to migrating smolts and returning adults associated with high 

 levels of dissolved nitrogen resulting from spill? 



There are certainly risks to migrating smolts and adults associated with high lev- 

 els of dissolved nitrogen fi-om spill. The program for spill that was developed by the 

 NMFS recognizes those risks and limits the dissolved gas levels fi'om fish spill. The 

 operation of the hydrosystem is not benign to passing juvenile and adult salmonids. 

 Passing the structure itself and through the slack water lake created by each project 

 imposes mortality on fish. The responsibility of the resource management agencies 

 is to adjust the passage of fish through the hydrosystem in a way that optimizes 

 fish survival. Passage over the spillway is the most benign of the project passage 

 routes, and if total dissolved gas levels are kept low enough, the benefits of spill 

 passage exceed the detrimental effects imposed by high gas levels. The dissolved gas 

 levels specified by the NMFS are conservative relative to the recommendations fa- 

 vored by the state and tribal fishery resource agencies. The recommendations of the 

 states and tribes and the justification for those recommendations is contained in the 

 drafi; 1995 SpUl and Risk Management. 



4. Have there been investigations of the effect of supersaturated water on resident 

 fish? Have the results of these studies been incorporated into current policy? 



The concern regarding the effects of dissolved gas on resident species has not been 

 investigated on tiie Columbia and Snake systems to the extent that research has 

 been conducted on salmonids. However, studies conducted on other river systems 

 have prompted the region to be concerned regarding the impact of TDG on fish that 

 are spending longer periods of time exposed to higher levels. Therefore, the NMFS 

 has incorporated tasks related to assessing the extent of signs of GBT in resident 

 fish and invertebrates into its monitoring efforts. In addition, the distinction has 

 been made, at least by the state agencies, regarding their preferential management 

 for native salmon over introduced exotic species. 



5. To what extent has scientific research from the states been incorporated into the 

 current spill policy? How can the decisionmaking process be improved? 



To my knowledge the research conducted by the states has been incorporated into 

 the current spill policy. There are some that view the current spUl program as more 

 conservative than necessary but support its implementation. The monitoring pro- 

 gram currentiy being implemented is based on the recommendations of the expert 

 panel on dissolved gas convened by NMFS and on recent research results on signs 

 of gas bubble trauma. Additional research is being conducted in 1996, which will 

 be incorporated into future monitoring programs. Research and monitoring rec- 

 ommended by state, tribal. Federal and private special interest consultants have 

 been incorporated into the monitoring and into the research programs for 1995. In- 

 dividual aspects of the present program are being conducted by state, tribfd. Federal 

 scientists and' independent consultants. Virtually all aspects of the impacts of dis- 

 solved gas trauma are presentiy being studied or will be addressed in the near fu- 

 ture. 



In 'Conclusion, spUl has been shown to be the safest route of dam passage. The 

 controlled spill for fish passage program was developed on the basis of past research 

 and monitoring. It was developed with broad regional input by public and private 

 entities. The spill for fish program was developed using a conservative analysis of 

 the risks and benefits associated with spiU and dissolved gas. An extensive research 

 and monitoring program has been implemented to verify the program. A broad 

 range of research and monitoring data is being collected to evaluate the impacts and 

 benefits of the spill program. All of this information will be incorporated into analy- 

 ses to evaluate the effect of recovery (measures on Snake River salmon). 



