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Fall Chinook Salmon

Fall chinook salmon were believed to return to the Umatilla subbasin as salmon were known to be captured from spring through the fall by Native Americans and early settlers. Natural production potential is theoretically large based on the juvenile life history patterns of fall chinook.

State and tribal authorities began hatchery releases of fall chinook salmon in 1982 with Tule stock, and switched to Upriver Bright stock in 1983 (Evans 1984). The suitability of the Umatilla subbasin for the natural production of fall chinook in its current condition has remained a critical uncertainty. Returns of hatchery produced adults has often been low with the largest adult return in 1999 of 737 adults. Low returns and the need for broodstock has limited harvest and natural spawning in most years (Table 23). However, outplanting of adult hatchery fall chinook from other mid-Columbia hatcheries has produced good survival to spawning and good redd numbers (Contor et al. 2000). Production of fry has also been documented, even though redds have been scoured by high flow events and impacted with fine sediment (Contor et al. 2000). ODFW (Knapp et al. 2000) estimated that 141,000 fall chinook fry migrated from the Umatilla River in 1998. Fry survival has been severely compromised by warm water temperatures during outmigration below Westland Dam, where most of the early summer flows are extracted. Additional water has been released into July during the last several years to assist down stream migration and enhance survival (Figure 33).


Fall chinook spawning has been observed primarily from the mouth of the Umatilla to the confluence of Meacham Creek (RM 79.0) with most of the spawning in the Barnhart (RM 42) to Yoakum (RM 37.0) reach. CTUIR estimates that most of the spawning occurs just below Barnhart where the majority of adult spawners are released.

Table 23. Umatilla fall chinook adult returns, disposition and spawning escapement, 1988-2000.


YEAR

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

Adult CHF Enumerated at TMD

91

271

329

522

225

368


692

595

646

354

286

737

643

Jack CHF Enumerated at TMD

195

267

113

468

79

29

230

291

80

207

154

137

437

Subjack CHF Enumerated at TMD

1268

65

618

273

0

15

367

343

606


189

230

152

4948

CHF Sacrificed or Mortalities at TMD

921

333

192

731

6

8

166

195

95

159

78

67

409

CHF Taken for Brood Stock

0

0

0

348

211

385

0

0

576

300

201

465

603


Adult Female CHF Released above TMD

?

?

?

57

7

6

305

213

9

30

5

133

59

Adult Male CHF Released above TMD

?

?

?

112

29

27

288

302

79

12

84

147

10

Total Adult CHF Released above TMD

58

192

168

169

36

33

593

515


88

42

89

280

69

Jack CHF Released above TMD

138

78

89

18

51

7

213

255

53

131

114

99

298

Subjack CHF Released above TMD

0

0

611

0

0

12

317

264

520

118

188

115

4647

Adult Female CHF Outplanted in Umatilla

0

0


0

0

0

0

0

0

423

483

74

433

-

Maturing Male CHF Outplanted in Umatilla

0

0

0

0

0

0

0

0

285

457

126

458

-

Total Females Available for Spawning

-

-

-

57

7

6

305

213

432

513

79

566

-

Total Males Available for Spawning


-

-

-

130

80

46

818

821

937

718

512

819

-

CHF Redds Observed




0

0

0

0

0

82

9

170

301

6

89

-

Unidentified Redds Observed




92

50

18

0

0

7

1

1

22

24

25

-


Figure 33. Life history chart of naturally produced Umatilla fall chinook salmon; shaded ovals represent areas and times where redds are at risk from scouring and/or sedimentation during high flows; shaded rectangles and red arrows represent times and areas where high water temperatures may be limiting (Contor et al. 1998).






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