TROUT, DUCKS, BEAVERS, 0R SALAMANDERS by Dan McAskill 
     
    
   
   
    
     For those individuals owning or managing streams, the old saying “May you 
     
     live in interesting times" is certainly applicable in these "new" times. The 
     
     pressures created by the demands to allocate primary or exclusive use of our 
     
     waters to conflicting uses has again returned to our streams. In the last 
     
     century it was water powered dams, clay road erosion, and sawdust pollution 
     
     that conflicted with free passage of trout, salmon, and other fish. Now it is 
     
     conflicting demand from fish farming, salmon and trout enhancement, waterfowl 
     
     enhancement, irrigation, fur bearer management (beavers), and other uses. 
     
    

    
     The first of the problems arises from 
     
     exclusive use of a section of water. A 
     
     good example of this occurs when a pond is 
     
     converted to an in-stream caged fish farm 
     
     for angling purposes. If the owner does 
     
     not utilize appropriate netting over the 
     
     cages, fish predators such as Belted 
     
     Kingfisher, Double- crested Cormorant, 
     
     Great Blue Heron, Osprey, or mink can 
     
     quickly become a problem for the fish 
     
     farmer. The ensuing predation can lead to 
     
     requests for special permits to remove the 
     
     "problem" birds or mammals. Another aspect 
     
     of in-stream cages is the buildup of fish 
     
     food under the cages or an increase in 
     
     feces from large numbers of fish in a 
     
     small area. Both can create water 
     
     pollution problems. Predator problems can 
     
     also occur from other types of fish farms 
     
     if they do not use enclosures around their 
     
     cages. 
     
    

    
     A second type of conflict arises from water withdrawal from streams. If 
     
     the water is returned directly to the stream unchanged chemically or thermally 
     
     e.g. low-head hydroelectric siphon systems, the only management concern may be 
     
     preventing fish from being sucked into the pipe and the mortality caused by 
     
     fish hitting the turbine blades. Regulations limit the volume of water that can 
     
     be removed from a stream during the various portions of the year and screens 
     
     must be installed to divert fish from the entrance. In addition, water 
     
     specialists have developed equations to assist in calculating the natural flow 
     
     rates of different streams. However, not all water withdrawals return water to 
     
     the stream at the same temperature or chemical quality. If the water is used to 
     
     culture fish, it will pick up nitrogen and other materials from the feces, 
     
     food, or medications. Properly handled, the water quality problems can be 
     
     minimized but the compounding effect of multiple developments on single streams 
     
     could lead to problems. In addition, cultured fish escapes from the aquaculture 
     
     facility can cause genetic shifts in the native fish or introduce new species 
     
     or problems to a stream. Irrigation water is still another reason for removing 
     
     stream water. Unfortunately, irrigation water is needed most during dry years 
     
     and the steam flow is already reduced. A considerable portion of the irrigation 
     
     water evaporates and that which does not must either percolate down through the 
     
     soil or run across the land to return to the steam. In either case it will pick 
     
     up additional chemicals. 
     
    

    
     The latest conflict has been present for some time but is only now 
     
     becoming recognized as a potential problem. One of the primary means of 
     
    
   
   
    
       
     
    
   
   
    
     Black Duck 
     
    
   
   
    
         
     
    
   
   
    
     Brook Troul 
     
    
   
   
    
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