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Spring Chinook

The Umatilla River is believed to have once supported large runs of spring chinook salmon, but the populations have since gone extinct (CTUIR and ODFW 1990). Van Cleve and Ting (1960) reported that there was a large return of chinook salmon in 1914 and that Indians and non-Indians caught thousands and thousands of salmon from spring to fall. The last sighting of the Umatilla run of spring chinook was in 1963 (Oregon State Game Commission 1963). Spring chinook were reintroduced to the subbasin beginning in 1986 using Carson stock (CTUIR and ODFW 1990). The current management objective is to return 8,000 adult spring chinook salmon to the Umatilla River (excluding ocean and out-of-basin harvest). The objective is to allow an escapement of 3000 fish for natural spawning, take 1000 fish for brood stock and harvest the remaining 4000. The spring chinook population is considered a key species because of its historical presence, recently demonstrated natural production potential and its tribal and non-tribal cultural significance.

The number of adult spring chinook returning to the Umatilla River has fluctuated in recent years with returns of greater than 2000 adults in 1990, 1996 and 1997, and 2000 (Table 19; Figure 27).


Table 19. Umatilla spring chinook adult return, spawning and harvest summary data.

YEAR

1989

1990

1991


1992

1993

1994

1995

1996

1997

1998

1999

2000

H-CHS Adults Enumerated at TMD

68

2158

1294

461

1202

261

389

2074

2033

343

1742

3874

N-CHS Adults Enumerated at TMD




















77

161

66

22

346

Total CHS Enumerated at TMD

68

2158

1294

461

1202

261

389

2151

2194

409

1764

4220

Jacks Enumerated at TMD

96

32

36

3

19

10

107

122

4

20

210

123

CHS Sacrificed or Mortalities at TMD


36

25

234

200

165

31

55

57

58

11

79

29

CHS taken for brood Stock

0

200

0

0

0

0

0

0

600

202

631

619

Adults Released above TMD

64

1949

1085

263

1050

235

378

2132

1537


207

1138

3562

Jacks Released above TMD

64

16

11

1

6

5

63

84

3

9

126

94

Ad. Clip. CHS Released above TMD

3

685

479

135

603

133

    162

572

400

38

327

1281

Harvest above TMD- CTUIR

0

N/D

82

0

176

0

0


167

187

0

110*

695*

Harvest above TMD- ODF&W

0

20

23

0

18

0

0

206

31

0

11

143**

Adults Available to Spawn

128




980

263

856

235

378

1759

1319

207

1020

2724

Adults Sampled on Spawning Grounds

6


272

228

78

471

112

194

715

667

89

539

1388

Jacks Sampled on Spawning Grounds

-




2

1

3

1

22

24

1

2

40

32

Adult Percent Recovered (After Harvest)

4.7

13.8

23.3

29.7

55.0

47.7

51.3

40.6

50.6

43.0


52.8

51

Number of Ad Clips Sampled

0

83

136

39

356

50

78

166

182

17

137

394

Percent Ad Clipped Adults Recovered

0.0

12.1

28.4

28.9

59.0

37.6

48.1

29.0

45.5

44.7

41.9

30.8

Prespawning Mortalities Sampled (Adults)

?

?

88

22


124

19

60

256

230

28

157

227

Prespawning Mortalities Sampled (Jacks)

-




1

1

1

1

10

5

0

0

13

7

Spawned Out Adults Sampled

?

?

130

48

336

93

126

440

401

61

361

1102

Spawned Out Jacks Sampled






1





2

0

11

19

1

1

27

20

Redds Observed

14

289

144

59

224

74

90

347

288

60

292

721

Spawned Out Females Sampled

?

?

81

37

205

56

73

267

244

41

228

689

*harvest includes 12 gaff mortalities in 1999 and 17 gaff mortalities in 2000; **does not include 441 adults harvested below Three Mile Dam.

Figure 27. Natural and hatchery spring chinook returns to the Umatilla subbasin 1989-2000 (Contor et al. 2000).

The highest returns are still below the objective of 8,000 adults. The number of jack spring chinook has also fluctuated between 58% in 1989 and less than 1% in 1997 (Table 19).

Returning adult hatchery spring chinook have been allowed to spawn naturally in the Umatilla River. Returns from natural spawners began in 1996 and increased to over 300 in 2000 (Figure 27). There is an estimated 1,549 acres of spring chinook spawning and rearing habitat in the Umatilla Subbasin (Northwest Power Planning Council 1988). The United States vs. Oregon Production Report estimated the chinook natural production capacity at 43,500 smolts and 870 adults (ODFW 1987, cited in CTUIR and ODFW 1990). Of the 770 total miles of stream habitat in the Umatilla Subbasin, only 64.5 miles (8.4%) were deemed suitable for chinook salmon (Contor et al. 1996).


Quality spawning areas are limited to the North Fork Umatilla River and the mainstem Umatilla River above RM 79 (Table 20, Figure 28). The number of redds observed and the estimated egg deposition has fluctuated through the years and has been determined by the number of adults available for spawning and their rate of survival to spawning (Figure 29 and Figure 30). Spawning surveys indicate that survival to spawning is often well above 90 % in the quality headwater habitat, but can be very low in the marginal habitat (Figure 30). During the last three years more and more adult spawners have been observed in the quality spawning habitat in the headwaters. Most spawned-out carcasses of naturally produced adults are observed in quality headwater habitat, and their numbers are increasing. A portion of the naturally spawning hatchery adults select marginal habitat with warm water temperatures and have poor survival to spawning (Figure 30). Figure 31 summarizes the percent of observed Umatilla adult spring chinook carcasses that had spawned successfully by river mile from 1991-1997.

Table 20. Spring chinook redd distributions, 1989-1996 (Contor et al. 1997; Contor et al.1998)


River Section

1989

1990

1991

1992

1993

1994

1995

1996

1997

N.F. Umatilla

0

68

13

10

27

16

13

51

47

RM 86-89.5

14

174

21

13


25

13

21

57

71

RM 83-86

29

15

14

6

10

50

72

RM 80-83

0

26

13

31

9

13

44

37

RM 78.9-80

0

20

6

39

14

13

34

10

RM 76.7-78.9

0

36

7

29

19

RM 73.6-76.7

0

0

0

25

2

4

42

12


RM 70-73.6

0

0

0

0

0

0

0

21

12

RM 67.5-70

0

0

0

0

0

0

0

8

0

Meacham Creek

RM 1-15


0

11

35

1

63

14

9

11

8

TOTAL

14

287

144

59

224

74

90

347

288

Figure 28. Umatilla spring chinook adult returns and the number of redds observed on spawning grounds, 1989-1999.

Figure 29. Spring chinook distribution, spawning and rearing areas in the Umatilla subbasin


Figure 30. Umatilla spring chinook adult returns and the estimated number of eggs deposited in redds.


Figure 31. Percent of observed Umatilla adult spring chinook carcasses that had spawned successfully plotted by river mile from 1991-1997.


Estimates of juvenile spring chinook rearing in the Umatilla Subbasin were based on the amount of suitable rearing habitat estimated during basin-wide habitat surveys, densities observed at annual index sites and intensive biological sampling in primary rearing areas. CTUIR estimated only 50,000 naturally produced juvenile chinook reared annually during the summer low flow periods from 1993-1996 (Contor et al. 1996).

Only in 1993 did significant adult spawning escapement occur during the brood years from 1992 to1995. In 1999 and 2000 spawning escapement and success was greater and the abundance of juvenile chinook has been much higher than normally observed (Contor, CTUIR, report in process). From natural population estimates (1993-1996), biologists identified that the areas with the highest densities of spring chinook were from RM 64.2 to RM 81 of the Umatilla River, in the North Fork Umatilla and in North Fork Meacham (Contor et al. 1998). (Table 21).

Table 21. Juvenile spring chinook abundance estimates in the Umatilla subbasin (Contor et al. 1996).


Reach

Length (mi)

Suitable Miles

Chinook/ Mile

Total Chinook

Umatilla River

(RM 64.2-81.8)



17.6

17.6

1250

22,000

Umatilla River (RM 81.8-89.6)

7

7

1441

10,087

N.F. Umatilla River

10

3

1500

4500

N. F. Meacham Creek

10

4

1000

4000

The distribution of the majority of juvenile spring chinook rearing habitat is limited to the North Fork Umatilla River and the mainstem of the Umatilla River above the mouth of Meacham Creek (Figure 29); however, juvenile spring chinook are also found in low numbers in the more favorable reaches of many of the tributaries used by juvenile steelhead (Contor et al. 1998). Residualization by juvenile hatchery spring chinook occurs at low levels and fewer than ten per year are observed at summer index sites. The abundance and distribution of naturally produced juvenile spring chinook during the summer is variable. The number of successful spawners the previous year and the extent of stream habitat with suitable water temperatures has varied considerably during the 1990s. Suitable stream habitat during cool wet years is considerably greater than during drought years (Contor et al. 2000).

Spring chinook expand their distribution during the fall, winter and spring and use habitat outside of the summer refuge areas (Figure 32). In April of 1997, when water temperatures were cooler and flows were higher, surveyors found low numbers of juvenile chinook lower in the watershed and in intermittent streams such as Thorn Hollow Creek, Saddle Hollow and Shaplish Canyon Creek (Contor et al. 1998)

Figure 32. Life history chart of naturally produced Umatilla spring 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).


Harvest of adult spring chinook is closely monitored and controlled by the timing and length of season as well as the location of the fishery. Harvest levels are set depending on the number of returning adults. Harvest is prohibited in prime spawning areas (above RM 81.7). Quotas are established based on the run size and seasons are closed when quotas are met. Adult returns have been sufficient to allow harvest during five of the last eight years. In 2000, tribal and sport anglers harvested and estimated 1279 adults spring chinook salmon from the Umatilla River (Table 22).

Table 22. Harvest estimates of Umatilla subbasin spring chinook (Contor et al. 1998).




Year

Tribal Harvest

Sport Harvest

Columbia and Snake River Harvest

1988

N/D

N/D

418

1989


0

0

127

1990

N/D

20

351

1991

82

23

49

1992

0

0

10

1993

176

18

29

1994

0

0

31

1995

0

0

46

1996

167

206

0

1997

187

31

N/D

1998


0

0

N/D

1999

110

11

N/D

2000

695

584

N/D





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