Table 4. --Number and kinds of fish passed by Snake Island 

 fishway, Potomac River, spring of 1963 



Date 



Operative conditions 



8 a.qi. 



water 

 temper- 

 ature 



Needle 

 weirs 

 out 



Stoplog 



openings 



closed 



Fishway 

 trap 

 lifts 



Fish passed 



Sucker 



Blue- 

 gill 



Chan- 

 nel 

 cat- 

 fish 



Number 



Total 



10 



10 

 10 

 10 



10 

 10 

 10 

 10 

 10 



10 

 10 



Number 



Number 



2 1 



2 1 



2 1 



2 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



3 1 



Number 



Number 



Number 



22 



3 

 4 

 1 



14 



over a 27-day period; 2 to 20 striped bass 

 over a 20-day period; 1 to 23 alewives over 

 a 17-day period; 7 to 17 white perch over a 

 12-day period; and 3 hickory shad over a 

 5-day period (table 5). American shad lived 

 1 to 15 days in the holding pen (average 

 of 4 days), striped bass 1 to 17 days (aver- 

 age 6 days), white perch and alewives 1 

 to 9 days (average 4 days), and hickory 

 shad 5 days. Water temperature in the holding 

 pen ranged from 13.3° to 20.6° C. 



During the experiment, the fishway was 

 operated with various connbinations of attrac- 

 tion flow. We made daily observations of 

 fish behavior and lifted the trap in the fish- 

 way exit 67 times. None of the fish placed 

 in the pen was trapped or seen in the fishway 

 transportation pools. All species made random 

 movements in the pen but at no time did the 

 fish appear to be schooled. American shad 

 usually swam near the surface in the calm 

 waters of the attraction chamber; the other 



10 



