106 



BULLETIN OF THE BUREAU OF FISHERIES 



OBSERVATIONS AFTER ELECTRICAL TESTS 



All of the fish used in tests 1 to 30, inclusive, except those killed outright, were 

 kept, segregated by test numbers, in the running water of the hatchery troughs for 

 observation. Check groups taken from the same hatchery pools, which had not 

 been subjected to any potential, were used for comparison. These fish, totaling 407 

 in number, were observed very carefully twice daily for 10 days. During this period 

 the fish that had been subjected to the electrical tests did not develop a single symptom 

 that did not develop in the check groups as well. During the fii'st two days of 

 observation one fish that had been subjected to a high-voltage gradient became 



Fio. 7 



blind, and it was thought at first that it was due to an electrical injury. Later, 

 however, fish in the check groups became blind in the same manner. During the 

 observation period 9 of the 407 fish became blind in one eye. This blindness prob- 

 ably was caused by mechanical injury in the close confinement of the hatchery 

 troughs. The male and female chinook salmon used in tests 13 and 14 of Table 1 

 were taken from a group of 21 being held in one of the ponds on Tanner Creek for 

 spawning purposes. These salmon had scars by which they could be identified, and 

 after reviving from an electrical test they were returned to the pond. These fish 

 spawned later, and Eugene Howell, the superintendent of the hatchery, reported that 

 milt and eggs were normal and did not show any evidence of sterilization. 



