Table 15. — Escapement recoveries of marked chinook salmon of 1961 brood by location of re/ease and recovery and age of 



capture, 1963-66 



Recovery location - 



Release location ' 



Elokomin 



Age 



Age 



Ape 



Spring Creek 

 Ape 



Grays River. 



Big Creek 



Plympton 



Elokomin 



Abernatliy.-- 



.N umber offish. 



Toutle. 



Kalama --. 



Lewis River (Speelyai). 

 Washougal, 



45 , 

 4 



Tanner Creek (Bonneville). 



Ea^le Creek (Cascade) 



Herman Creek (Oxbow) 



Wind River.. 



35 



Little White Salmon. 



Spring Creek 



Big Wliite Salmon. . . 



1 



42 308 141 



Klickitat., 



Total 2 S 3 13 176 



Number of strays U 7 3 6 5 



Percentage strays 77.S 100.0 46.2 2.8 



Percentage strays (all ages) 71.4 6.3 — 



2 



4 



41fl 148 3 



IS 7 1 



4. 3 4. 7 33. 3 



... 4.9 



40 4 52 22 



4 3 17 10 



8.2 75.0 32.7 54.4 



... 38.0 .... 



46 

 4 



8.7 



1 Elokomin? LV-RM; Kalama: Ad-RV-RM and Ad-RV; Oxbow: RV-RM; Spring Creek: Ad-LV-RM and Ad-LV. 



= Recoveries in tributary streams were adjusted on the basis of the appropriate sampling ratios. Recovery locations are arranged in upstream order (see 

 fig. 1). 



River. A smaller fraction of the fish under 80 cm. 

 (31.5 inches) long returned to Spring Creek than 

 did the group over 80 cm. long (3-year-old chinook 

 at Spring Creek average about 80 cm.) . 



These results offer an alternative explanation 

 for the observed increase in the marked to un- 

 marked ratio with age of return. That is, if the 

 proliability of straying is greater for younger fish 

 than for older fish, as indicated above, then it is 

 likely that the marked to unmarked ratio would 

 increase witli age even if marking had no effect on 

 maturation. 



Additional information of the effect of marking 

 on maturation will be available later from the TM 

 50 marking experiment at Little White Salmon 

 Hatchery. For the ))reseiit, we will assume that 

 marked and unmarked lOfil-lirood hatchery fish 

 had tlie same maturity schedule. 



Another point of interest in table 15 is that the 

 fisli generally strayed to areas near the hatchery 

 of origin. Except for the one marked fisli from 

 Spring Creek recovered in the Kalama system all 

 marked fish recovered at any great distance from 

 the liatcliery of origin were recovered upstream. 

 If the pattern of straying is the same for non- 

 liatchery fish, it is possible to obtain a maximum es- 

 timate of straying of nonhatchery fish into the four 

 selected hatcheries — Cascade, Oxbow, Little White 



Salmon, and Spring Creek. These hatcheries are 

 between Bonneville and The Dalles Dams (fig. 1). 

 Most of the fall chinook salmon return to tliese 

 hatcheries during the last week of August and 

 September. Spawning occurs between mid-Septein- 

 Ijer and mid-October but is generally concentrated 

 within a 2-week period. 



Most (about 70 percent in 1965) of the fall 

 chinook salmon that passed The Dalles Dam be- 

 tween August 26 and September 30 are generally 

 brightly colored and are thought to spawn as much 

 as a month later than the darker hatchery fish."' ** 



Because of the short duration of spawning at the 

 four hatcheries, it is not likely that fish destined 

 for areas above Tlie Dalles Dam would contribute 

 substantially to these hatchery returns. This gen- 

 erally agrees witli the indicated "upstream" stray- 

 ing of the marked hatcliery fish. That is, straying 

 probably conies primarily from populations of fish 

 that normally spawn near or downstream from tlie 

 four hatcheries. 



' Smith. Eugen(> M. 19fi6. Final report. A study to identify the 

 race of fall chinook salmon whose spawning sround.s will be 

 innndatcd by the .John Day impoundment on the Columbia River. 

 Fish Comm. Oreg. Res. Div. (U.S. Army Corps Eng.. Walla Walla 

 Dist.. contract D.i— to-164-CIVEXG-66-.T) . OM pp. I Processed.] 



* McKee. Thomas B. 1966. Deschutes River adult fall chinook 

 holding study, 1965. Fish Coinm. Oreg. Res. Div. (U.S. Army 

 Corps Eng., Walla Walla Dist., contract DA-1.'5-164-CIVENG- 

 66-7), 26 pp. [Processed.] 



382 



TT.S. FISH AXD WILDLIFE SERVICE 



