This type of electrical field has proved 

 highly efficient in the diversion of Chinook sal- 

 mon. The longest a recognizable fish has been 

 observed in the area of the ground line has 

 been 2 days . In addition no concentration of 

 Chinook salmon collected below the weir, in- 

 dicating that this species was being diverted 

 into the ladder with no appreciable delay. 

 These observations are in sharp contrast to 

 those made at a conventional picket weir in- 

 stalled in exactly the same location in years 

 before 1953. Some of the chinook salmon per- 

 sisted in fighting the conventional weir for two 

 weeks or longer. As a result concentrations 

 of fish built up below the weir and injuries to 

 the fish, particularly in the head region, were 

 common. 



The reactions of sockeye salmon to the 

 electrical barrier have been slightly different 

 from those of chinooks. These fish appear in 

 fairly large schools in deeper parts of the river 

 about 200 yards below the weir. Occasionally 

 a fish will move out of the school and proceed 

 upstream at a high rate of speed. When it en- 

 ters the electrical field to a depth of from 6 to 

 8 feet it jumps out of water, reverses its direc- 

 tion, and proceeds as rapidly downstream. Un- 

 like the Chinook, the sockeye have never been 

 observed to work along the ground line, yet 

 they move readily into the holding ponds . Whole 

 schools disappear from the river and appear in 

 the holding ponds overnight. Undoubtedly the 

 movement of these fish is directed toward the 

 fish ladder by the angle lead of the electrical 

 field. 



Andrew, Johnson, and Kersey (1956) state 

 that an angled electrical field created by a double 

 curtain of electrodes, 4 feet apart between rows 

 and spaced 3 feet apart within rows, had no lead- 

 ing effect on either sockeye or pink salmon . 

 These tests were conducted using direct current 

 and only for 30-minute trial periods. The ob- 

 servations at Entiat indicate little probability 

 that the fish would become conditioned to an 

 electrical stimulus within a 30-minute period. 

 The lack of conditioning, location of the bypass, 

 and the uneven voltage gradient surrounding the 

 electrodes in this experimental installation 

 would make these tests a biased measure of the 

 leading ability of electrical fields. Leading, in 

 this instance, is defined not as an orientation 



toward one pole of a direct current field but 

 rather as the diversion of the fish away from 

 an electrical field and into an alternate passagje. 



It has been impossible to demonstrate 

 any deleterious effects from electrical diversion 

 either on the survival until maturation of the 

 adult salmon diverted by the weir or on their 

 resulting progeny. Because all fish procured 

 for artificial propagation since 1953 have been 

 diverted by the electrical field, the only com- 

 parisons possible have been with previous years . 

 The many additional variables other than elec - 

 trical diversion make this a crude measure at 

 best . The survivals of both the adults and 

 fingerling are well within the range encountereid 

 in previous operations. 



A few females in 1953 and 1954 received 

 sufficient shock to induce spinal curvature . 

 These fish survived to spawning and produced 

 normal appearing eggs . In 1954 the eggs from 

 2 females were held separately and the viability 

 of the eggs compared with those derived from 

 females which were apparently normal. The 

 survival rate was higher in the eggs from the 

 severely shocked females than in the eggs from 

 the normal fish . Individual variation between 

 females was assumed to be the cause for the 

 differences in survival. Since 1954 no females 

 with spinal dislocations have been observed. 

 The indications are that even severe electrical 

 shock incurred on the upstream migration, whdn 

 the eggs are at least 2 weeks from maturity, has 

 no deleterious effect on egg viability. 



Downstream migrant salmon fingerlings 

 pass through the electrical field of the weir with 

 impunity. According to McMillan (1928), fingeor- 

 ling Chinook salmon must be exposed to a gradient 

 of 1 . 5 volts per inch for 1 minute before they are 

 killed. Voltages of this magnitude occur only ih 

 the area immediately adjacent to the electrodes 

 at a maximum distance of not more than 6 inches 

 from the electrodes. Fingerling salmon, 4 to 5 

 inches in length, have been observed moving 

 freely both upstream and downstream within th$ 

 electrical field. Only when they approached to 

 within 3 or 4 inches of an electrode were they 

 temporarily stunned. Large whitefish (ProsopiUm 

 williamsoni ), 12 to 14 inches in length, intro- 

 duced immediately above the electrodes, were 

 immobilized and carried through the field btiT 



