Table 3. --Number and kinds of fish passed by Snake Island fishway, 

 Potomac River, spring of 1962 



Date 



Operative conditions 



8 a .m. 

 water 

 temper- 

 ature 



Needle 

 weirs 

 out 



Stoplog 



openings 



closed 



Fishway 

 trap 

 lifts 



Fish passed 



Sucker 



Blue- 

 gill 



Chan- 

 nel 

 cat- 

 fish 



Carp 



April 30 



May 7 



8 



9 



10 



11 

 12 

 14 

 15 

 16 



17 

 18 

 21 

 22 

 23 



24 

 25 

 26 

 27 

 28 



29 

 30 

 31 



Total 



15.5 

 17.7 

 17.2 

 15.6 

 15.5 



15.5 

 15.7 

 18.8 

 20.0 

 21.1 



22.2 

 23.3 

 23.3 

 22.2 

 22.2 



22.7 

 23.3 

 23.8 

 23.3 

 22.2 



23.3 

 23.3 

 23.3 



Number 



5 

 5 

 5 

 5 

 5 



5 

 5 

 6 

 6 

 6 



6 

 6 

 6 

 6 

 8 



8 

 8 



8 

 8 

 8 



Number 



2 

 1 

 1 

 1 

 1 



1 

 1 

 1 

 1 

 1 



1 

 1 

 2 

 2 

 2 



2 

 2 

 2 

 2 

 2 



2 

 2 

 2 



Number 



1 

 1 

 3 

 2 

 4 



2 

 3 

 5 

 6 

 5 



5 

 4 

 4 

 3 

 2 



4 

 2 

 2 

 3 

 1 



1 

 3 

 2 



Number 



Number 



Number 



Number 



68 



14 



18 



2 

 2 

 2 



10 

 8 

 2 



16 

 2 



3 

 6 

 4 



63 



Fish counted through the fishway trap in- 

 cluded: 1 sucker, Z bluegills, and 14 channel 

 catfish (table 4). No anadromous species 

 were trapped or seen in the fishway system. 



Fish Behavior in Holding Facility 



Fronn April 22 to 24 and April 29 to May 

 23, we observed the behavior of anadromous 



fish placed in a holding pen immediately below 

 the fishway entrance. The pen was made by 

 placing a wire screen in one of the stoplog 

 openings, while the stoplogs were left in 

 place in the other openings (fig. 5). The 

 only escapement route for captive fish was 

 upstream through the fishway. 



The number of each species held in the 

 pen on any 1 day was: 1 to 43 American shad 



