Table 3. — Numbers of marked juvenile sockeye salmon 

 recovered in scoop traps at the Interstate Bridge after 

 release in the spillway (S) or turbines (T) of Brovmlee 

 Dam, March 31 to May IB, 1966 



Date (1965) 



Fish 

 released 



Release 

 site 



Average 

 spill 



Fish recovered 



Number 



March: 



31 241 T 



April: 



1 95 S 



2 109 T 



5 177 S 



5 275 T 



6 140 S 



7 211 T 



8 238 S 



9 lOB T 



10 218 S 



10 103 T 



11 124 S 



12 180 S 



14 110 T 



16 140 S 



May: 



15... 207 S 



Total 2,670 



CM.Vkc.) Numbtt Percent 

 2.5 



487 



459 

 425 

 448 

 448 

 519 

 338 

 357 

 409 

 610 

 510 

 511 

 499 

 448 

 511 



2.1 

 1.8 

 2.3 

 2.9 

 1.4 

 1.9 

 2.1 

 4.9 

 1.8 

 2.9 

 4.8 

 1.1 

 3.6 

 3.6 



4.3 



2.66 



Table 4. — Numbers of marked juvenile salmon {chinook, 

 coho, and sockeye) recovered in scoop traps in the Brownlee 

 Dam tailrace between 8 a.m. and 4 p.m., 196^-66 



Total 



fish 



released 



Number released at Turbine 

 turbine number dis- 



charge Fish recovered 



12 3 4 



1964: 



July 3.. 



July 3.. 



July 4.. 



July 4.. 



July 6.- 



JulyS.. 



July 5. . 



July 7-. 



July 7.. 



July 7.. 



July 8.. 

 1965: 



June 6.. 



June 6.. 



June 6.. 



June7.. 



Total. 



Number 



200 

 200 

 200 

 200 

 200 

 200 

 200 

 200 

 200 

 200 

 200 



350 

 371 

 392 

 384 



Number offish 



100 . 

 100 . 

 100 

 100 . 

 100 . 

 100 , 

 100 



100 100 



100 100 



100 100 



100 100 



96 99 76 



99 100 79 



106 99 87 



95 92 105 



(.M.'laee.) 



618 

 612 

 439 

 448 

 379 

 399 

 375 

 387 

 443 

 417 

 536 



79 472 



93 472 



100 409 



92 547 



Num- Per- 

 ber cent 



100 

 100 

 100 

 100 

 100 

 100 

 100 



5 

 7 

 14 

 7 

 6 

 1 

 3 

 15 

 10 

 10 

 9 



13 

 17 

 22 

 12 



2.5 

 3.5 

 7.0 

 3.5 

 3.0 

 .5 

 1.5 

 7.5 

 5.0 

 6.0 

 4.5 



3.7 

 4.6 

 5.6 

 3.1 



3,697 1,096 790 747 1,064 



Bridge, these limits represent the 95-percent con- 

 fidence limits as computed by Chapman's formula : 



m, 7n=R-f 



1.96^ 



where 



v> 



±1.96-»/R-F 



1.96* 



(3) 



m and m are the upper and lower values of R, 

 respectively. 



Upper and lower estimates at the turbine tail- 

 race site were based on the 95-percent confidence 

 interval of the means of the frequency distributions 

 in the respective day-night tests of efficiency 

 (Wilkes, 1948). These values were computed ac- 

 cording to the formula: 



where 



n 



ti= population mean 

 .X'= sample mean 

 <„= confidence coefficient 

 s= standard deviation 

 n= number of tests 



Table 5. — Numbers of marked juvenile salmon {chinook, 

 coho, and sockeye) recovered in scoop traps in the Brownlee 

 Dam tailrace between 4 p.m. and 8 a.m., 1964-66 



Date 



Total 



fish 



released  



Number released at 

 turbine number 



Turbine 

 dis- 

 • charge Fish recovered 



1964: 



Julys.. 



July 4. - 



July 6... 



July?.-. 



July 11-- 



Julyll.. 



July 12.. 



July 12.. 



July 14.. 



July 15.. 



July 15.. 



July 15.. 



July 16.. 



July 17.. 



July 18. . 

 1965: 



June 5.. 



June 5.. 



June 6.. 



June 7.. 



Total. 



Number 



200 

 20O 

 200 

 100 

 300 

 300 

 200 

 200 

 200 

 100 

 800 

 200 

 300 

 200 

 300 



Number offish 



(.M.'Isec.) 



577 

 378 

 349 

 364 

 268 

 263 

 228 

 294 

 301 

 84 

 343 

 214 

 339 

 303 

 408 



409 110 100 99 100 553 



364 61 99 99 105 168 



381 94 96 101 90 159 



320 98 98 59 65 358 



Num- 

 ber 



10 

 9 

 13 



7 

 25 

 26 

 34 

 34 

 15 



6 

 27 

 28 

 89 

 12 

 34 



36 

 54 

 52 

 30 



Per- 

 cent 



5.0 

 4.5 

 6.5 

 7.0 

 8.3 

 8.7 

 17.0 

 17.0 

 7.5 

 6.0 

 9.0 

 14.0 

 29.7 

 6.0 

 11.3 



8.8 

 14.8 

 13.6 



9.4 



4,774 1,363 793 1,458 1,160 



11.33 



Estimates of annual emigration were based on 

 scoop trap catches from May 1963 tlirough Au- 

 gust 1965 (table 6). No tests of efficiency of scoop 

 traps were made in 1963; therefore, estimates of 

 emigration for that year were based on efficiency 

 tests in 1964. In the estimates of emigration, 

 catches by the Idaho Power Company barrier net 

 in 1964 were also included. Estimates of immigra- 

 tion used to compare with estimates of emigration 

 were from Krcma and Raleigh (1970). 



ESTIMATES OF EMIGRATION 



EMIGRATION OF NATIVE SALMON 



The migration of juvenile salmon and trout 

 from Bro\\'Tilee Reservoir included three native 

 and three hatchery-reared salmon populations and 

 a trout population of unknown origin. Estimates 

 of emigration were made for each population. 



Native juvenile salmon migrating through 

 Brownlee Reservoir included fall chinook salmon 

 and kokanee from the Snake River and spring 

 chinook salmon from Eagle Creek and the Weiser 

 River. 



JUVENILE SALMON AND TROUT EMIGRATION FROM BROWNLEE RESERVOIR 



249 



