DEPTH(M.) 



0-3.7 



3.7-7.3 



7.3-11.0 



11.0-14.6 

 14.6-18.3 



18.3-21.9 

 21.9-256 



DEPTH (M.) 



DEPTH (M.) 



0-37 



37-7.3 



7.3-11.0 



II 0-14.6 



14.6-18.3 



18.3- 21.9* 



219-25.6 



Period 3: 

 July 20,l964,to Morch 11,1965 

 3- day schedule 



Period 4: 

 April 12 to June 17, 1965 

 2 - day schedule 



Figure 4. — Cross sections of gill net sampling area showing daily fishing schedule for each sampling period. 



at night. Each trawl tow lasted about 15 

 minutes. The surface (0 to 3.7 m.), middle 

 (11.0 to 14.6 m.), and bottom (21.9 to 25.6 m.) 

 were sampled by towing the trawl at a speed 

 of 2.3 km. per hour (1.8 knots) and by letting 

 out 7.6, 45.7, and 76.2 m. of towing line, 

 respectively, from each boat. The distance 

 maintained between the boats was about equal 

 to the length of towing line used. 



After a tow was completed both boats stopped; 

 the net was lifted from the water and the 

 captured fish were identified, counted, and 

 measured (fork length). To prevent repeated 



sampling of the same groups, the fish were 

 taken to a holding tank and later released 

 below Mayfield Dam. 



The number of times each gill net and 

 trawling station was sampled varied. To com- 

 pare the relative abundance of fish among the 

 gill net fishing stations, as well as among 

 the eight trawling stations, a standard catch 

 per unit of effort was defined as the total catch 

 at any particular gill net or trawling station 

 divided by the number of times that station 

 was fished. 



