The efficiency of the nets was greatest 

 when they were new at the start of the season 

 and least at the end of the season, owing to a 

 gradual increase in number of holes and mended 

 sections. No correction was applied for re- 

 duced efficiency; it is not believed to be a 

 major factor because nets were discarded 

 when they reached a point where major re- 

 pairs were needed. On a few days nets over 

 the shallow littoral area were fouled with 

 detached periphyton, which also probably re- 

 duced efficiency. No correction was practical 

 in this case either. Good catches were often 

 made under these conditions, suggesting that 

 the fouling did not appreciably reduce a net's 

 catching ability. 



Fish were removed from the nets daily, 

 usually between 9:30 and 11 a.m., except 

 when bad weather occasionally made boating 

 unsafe. At the start of the season nets were 

 checked morning and evening, but so few 

 fish were caught during the day that the even- 

 ing check was discontinued. One or two men 



A.^A->A.>*-0 -a.&^-o- ^-^^BL. 



1/2 



■ U ^i i ii ) i | | jil i . i j 



3/4 7/8 



1 1/8 



1/2 



^ 



TYPE I 



,a>-a..ux-J.Q-0.. A.o, 



3/4 



1 1/2 



TYPE n 



TYPE 



::£ 



ii^r-^ 



TYPEm 



3/4 7/8 



1/8 



1/2 



3/4 



7/8 



i/e 



1/2 



3/4 



7/8 



1 1/8 



1/2 



3/4 



l'/2 



....cz 



1/2 



3/4 



7/8 



. ■ i p -* i j 



TYPE 1 

 ^374 T 3/4 T 



11/8 



TYPETZI 



* ' J.t l ,M ! l]IJ ' Jll ' . ' '-V 



TYPEini 



1/2 



3/4 



11/2 



O 12 



80 90 100 110 



FORK LENGTH (MM.) 



120 



Figure 19.--Lengths of juvenile sockeye salmon caught 

 in gill nets. Brooks Lake, June 1 toOctober.6, 1957. 



Figure 20.— Diagrammatic sketch of seven types ofgill 

 net sets used in sampling lake- resident juvenile 

 sockeye salmon in Brooks Lake in 1957. (All sizes 

 are stretch measure in inches.) 



checked the nets (fig. 22); two men were 

 necessary in rough water and desirable even 

 when the water was calm. Nets were left in 

 the water continuously, except when repairs 

 were made or the location changed. 



For each fish captured a record was made 

 of the species, net type, mesh size, and loca- 

 tion of fish in mesh (top, middle, or bottom), 

 fork length, weight, location and depth of 

 water of the set, and wind. Scales were taken 

 for age analysis. 



Five hundred and five juvenile sockeye 

 salmon were caught during the season in all 

 types of gill nets (table 9), with August being 

 the most productive month. Other species also 

 were caught and processed In the same way 

 as were the juveniles, with the exception of 

 adult sockeye salmon which were counted and 

 released. Scales were not preserved from 

 species other than sockeye salmon. 



29 



