The number of shad that were not able to ascend to 

 the counting barrier is not known, but after passing through 

 the counting gate many would not go on up the ladder. In- 

 stead they would mill about in the relatively quiet water 

 above the counting barrier, where they would weaken and 

 drift against the counting barrier and there die. A great 

 deal of effort was expended to induce the shad to go on 

 upstream. In 19U6 it was found that by placing two 

 equidistant xrooden walls or leads parallel with the sides 

 of the ladder above the Bradford Island counting station 

 thus creating three equal sized short channels, the shad 

 were prevented from moving back and forth above the count- 

 ing station by being constrained in the central narrower 

 channel. Somehow this treatment impelled more to go on 

 upstream for after this was done fewer dead fish were 

 found in the ladder. 



19U7 ; 



Again in 19^7, as in previous years, considerable 

 mortality occurred to the shad in the fish ladders after 

 these fish passed through the counting station, A record 

 of this mortality has been kept which indicated that l5.9^ 

 of the June shad that ascended the Bradford Island ladder 

 perished, whereas 7.1^ died in the Washington Shore lad- 

 der after being counted. The fish do not like to ascend 

 the last ten turbulent weirs into the forebay, and they 

 migrate upstream just as the forebay level is ten feet 

 higher than normal. 



From these notes it would appear that the shad mortalities 

 in the Bonneville fishways during past years resulted from the rigorous 

 conditions above the counting fence when high headwater levels prevailed, 

 and from the adverse effect of the quiet resting pools. One or both of 

 these factors has been listed as the cause of mortalities in every instance. 



During the 1950 run^ only minor mortalities occurred even though 

 the water levels were such that the two factors causing the prei/iously 

 mentioned mortalities prevailed. For the major part of the 1950 run the 

 forebay was held at elevation 82 and the ladders had to be adjusted to 

 this high level. In spite of this, mortalities were only 28 out of 7,8l8 

 shad counted. 



It is also encouraging to note that since 19U8 very few shad 

 mortalities have occurred. The resident biologist's notes on shad 

 passage for 19U8 states that the "losses were minor"; in 19U9 "the 

 shad were able to ascend with ease"; and in 1950 he states that there 



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