320 EIGHTH PACIFIC SCIENCE CONGRESS 



The special hazards which are faced by anadromous fish as a re- 

 suit of human activities have been mentioned previously. Perhaps the 

 most serious interference with natural conditions is produced by hydro- 

 electric developments which intrude impassable barriers to upriver sal- 

 mon, pass practically all of the water through their turbines, and create 

 great nev/ lakes in their storage reservoirs. Much effort is being put on 

 studies of methods to guide upstream and downstream migrating sal- 

 mon past obstructions. Culturing in coastal lakes or special nursery 

 areas may prove necessary and the conditions controlling survival are 

 being studied with that in mind. As hydro-electric power is in increas- 

 ing demand, there is a great sense of urgency in the researches which 

 seek means for preventing the destruction of the salmon fisheries. 



