Figure 17. — Stationary trap for catching juvenile sockeye salmon migrating upstream in Brooks River, 1957. 



juveniles is insignificant. At no time was any 

 large migration upstream noticed, although 

 personnel particularly watched for it. The few 

 sockeye salmon fry that were caught in the 

 trap probably originated in Brooks Lake, since 

 the area below the trap provided an excellent 

 resting place out of swift water for fish pausing 

 during their downstream migration. 



MIGRATORY BEHAVIOR OF 



JUVENILES AS DETERMINED 



FROM OBSERVATIONS 



2. Large schools of sockeye salmon fry 

 were observed at the outlet of Brooks Lake 

 and at the mouth of Brooks River, particularly 

 from mid-May to mid-June and again in Sep- 

 tember. These schools sometimes consisted 

 of thousands of fish. 



3. There was never any evidence of 

 significant upstream migration from Naknek 

 Lake or from Brooks River into Brooks Lake. 

 On the contrary, whenever fry were evident, 

 there was a continual downstream displacement 

 as indicated in part by (2) above. 



Observations of the migratory behavior of 

 juvenile sockeye salmon were made 39 times 

 between May 18 and September 27 on Brooks 

 River and Brooks Lake and its tributaries. 

 They are summarized as follows: 



1 . Yearling and 2-year-old sockeye salm- 

 on were evident to observers in appreciable 

 numbers in Brooks Lake or River only at 

 night at the outlet during the period of peak 

 outmigration in late May and early June. 



4. Sockeye salmon yearlings and 2-year- 

 olds migrated from Brooks Lake to Naknek 

 Lake within a single night. 



5. Lake (Salvelinus namaycush) and rain- 

 bow trout, which lie in schools at Brooks Lake 

 outlet during May and June, fed mainly on 

 floating insects drawn to the outlet by surface 

 current, but sometimes ate young salmon. 



6. Sockeye salmon fry in Brooks Lake 

 fed voraciously on periphyton, which breaks 



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