COMMERCIAL FISHERIES REVIEW 



Vol. 28, No. 9 



Receiver 

 Tank 



Air Curtain 



I" I . D . 

 Pipe 



1" I . D. polyethylene pipe 



First 250' I ,■,.-■ Second 250' 



V V vvVT M,Jl^1[JhI 



' 3/4" I . D . polyethylene pipe 

 ■ Second 250' ■ - ■ ' . 



€::=> <fr>0 ^ c^oO 



cD 



3 '8" chain 



Cross Section of Milwaukee River 



West : 

 Bank ; 



Fig, 6 - Diagram of air hose installation. 



MEASURE OF EFFECTIVENESS 



Gill netSj one on each side of the air curtain, were used to evaluate the number of fish 

 traveling through the air curtain. Because the rivers are navigated by pleasure boats and 

 other smaller craft, the nets had to be set below the normal draft of such boats. Gill nets were 

 6 feet deep by 100 feet long and made of l|--inch (stretch) nylon webbing. These nets extended 

 across the river so that fish near the bottom would be caught no matter at what point in the 

 river they migrated. To minimize the length of the nets needed, one was placed between the 

 abutments of the Buffalo Street bridge and the other between the abutments of the North Water 

 Street bridge (see fig. 2), The width of the 

 river at those points (between the abutments) 

 is about 100 feet. The nets were fished each 

 Monday, Wednesday, and Friday. The nets 



Fig. 7 - Air curtain with holes spaced at 6-inch intervals (0. 1 

 inch in diameter). 



Fig. 8 - Setting test net. 



