Draft Imnaha Subbasin Summary November 30, 2001 Prepared for the Northwest Power Planning Council Subbasin Team Leader


Appendix H - Northwest Power Planning Council (1990) Smolt Density Model – Fall Chinook

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Appendix H - Northwest Power Planning Council (1990) Smolt Density Model – Fall Chinook




StreamName

TributaryTo

From

To

Present

LengthMiles

WidthFeet

UseType

HabitatQuality

SmoltCapacity

Major Habitat constraints

Imnaha R

Snake R

Mouth

Cow Cr

100

4.30

65

Primarily spawning and rearing

Excellent

227799

low winter water temperatures

Imnaha R

Snake R

Cow Cr

Lightning Cr

100

1.10

75

Primarily spawning and rearing


Excellent

58274

low winter water temperatures

Imnaha R

Snake R

Lightning Cr

Horse Cr

100

5.40

80

Primarily spawning and rearing

Excellent

286073

low winter water temperatures

Imnaha R

Snake R

Horse Cr

Big Sheep Cr

100

11.50

80

Primarily spawning and rearing

Excellent

609230

low winter water temperatures



Appendix I - Hatchery Genetic Management Plan for the Imnaha Subbasin

(The following documents were not developed cooperatively with co-managers. ODFW developed it and submitted it to NMFS without co-manager review or comment. This HGMP also does not reflect the current program.)

SECTION 1.0 GENERAL PROGRAM DESCRIPTION

1.1) Name of Program

Imnaha River Spring/Summer Chinook Salmon

1.2) Population (or stock) and species

Oncorhynchus tshawytscha, chinook salmon (stock 029)
1.3) Responsible organization and individual
ODFW Portland Staff:
Name (and Title): Trent Stickell

Organization: Oregon Department of Fish and Wildlife

Address: 2501 SW First, Portland, OR 97207

Telephone: 503-827-5252

Fax: 503-872-5632

Email: Trent.W.Stickell@state.or.us


ODFW Regional Staff:
Name (and Title): Bruce Eddy

Organization: Oregon Department of Fish and Wildlife (ODFW)

Address: 107 20th Street

Telephone: 541-963-2138

Fax: 541-963-6670

Email: bruce.r.eddy@state.or.us

Co-Management Organizations: Nez Perce Tribe (NPT)

Confederated Tribes of the Umatilla Indian Reservation (CTUIR)



1.4) Location(s) of hatchery and associated facilities:

  • Adult holding, spawning, egg incubation, and rearing:
  • Lookingglass hatchery is located 18 miles north of the town of Elgin, adjacent to Lookingglass Creek 2.2 miles above its confluence with the Grande Ronde River at about river mile 86. Elevation at the hatchery is 2,550 feet above sea level. Adult facilities consist of a trap and two concrete raceways (4,560 ft3). Incubation is in 288 vertical incubator trays with a capacity of 2.3 million eggs to hatching. There are 32 Canadian troughs for starting fish each with a capacity of 100 to 125 pounds of fish. Rearing is in 18 concrete raceways (3,000 ft3) each with a capacity of 4,000 lb (Lewis 1996).


  • Adult collection, acclimation and release:

Imnaha collection and acclimation facility is located three hours from Lookingglass hatchery, approximately 30 miles from the town of Imnaha, adjacent to the Imnaha River at river mile 45.5. Elevation at the Imnaha facility is 3,760 feet above sea level. Facilities consist of an adult trap, spawning area and one pond (13,000 ft3). The pond is used for adult holding in the fall and juvenile acclimation and release in the spring. Capacity for juveniles is about 19,500 lb.
Other organizations involved and intent

The U.S. Fish and Wildlife Service, through the Lower Snake River Compensation Plan (LSRCP), funds production and operation expenditures at Lookingglass hatchery and Imnaha acclimation pond. The Nez Perce Tribe, Oregon Department of Fish and Wildlife, and the Confederated Tribes of the Umatilla Indian Reservation are co-managers of the Imnaha River spring/summer chinook salmon program.


1.5) Type of program:

The Imnaha River spring/summer chinook salmon (stock 029) fish propagation project is managed as a "mitigation" and "supplementation" program.


1.6) Purpose (Goal) of program (Nandor 1995):

Produce up to 3,210 spring/summer chinook salmon adults for in-place, in-kind mitigation.


1.7) Specific performance objectives(s) of program:
1.8) List of Performance Indicators designated by "benefits" and "risks"
1.9) Expected size of program

1.9.1 Expected Release -

Production goals for 1999 brood Imnaha spring/summer chinook salmon (AOP 1999):


  • 420,000 smolts released into the Imnaha River.

  • 70,000 smolts released into the Big Sheep and Lick Creeks.

  • Actual production will be based on egg take, with Imnaha River releases as first priority.




      1. Adult fish produced and harvested

The number of spring/summer chinook salmon collected at the Imnaha weir since 1990 is presented in Table 1. Estimated total adults produced from juvenile Imnaha spring/summer chinook salmon released for this program is reported in Table 2.
Table 1: Summary of spring/summer chinook salmon collected at the Imnaha weir and their disposition since 1990 (adults and jacks combined). Released = released alive above the weir. Retained = transferred to Lookingglass hatchery for brood stock. Data taken from ODFW Annual Report Series, Evaluation of Lower Snake River Compensation Plan Facilities in Oregon.


Brood

Unmarked Fish

Marked Fish

Year

Collected

Released

Retained

Collected

Released


Retained

1990

183

102

81

221

68

153

1991

223*

126

97

282

67

215

1992

413*

280

133

431

179

252

1993

650*

543

107

593

248

345


1994

72

52

20

91

60

31

1995

38

0

38

30

0

30

1996

145

73

72

99

23

76

1997

84

61

23

204

55

149

1998

150

73

77

236

136**

96

1999

73


51

22

323

69

254

* = In 1990 and 1991 not all the Imnaha spring/summer chinook salmon juveniles released were marked. Estimates of unmarked hatchery fish included in the above numbers are: 1991 = 92; 1992 = 253; and 1993 = 302.

** = Includes 25 fish out-planted to Big Sheep Creek and 14 fish out-planted to Lick Creek.


Table 2: Estimated total adult spring/summer chinook salmon produced from juveniles released as part of this program. Data taken from ODFW Annual Report Series, “Evaluation of Lower Snake River Compensation Plan Facilities in Oregon”. Strays = non-harvest freshwater recoveries outside the Imnaha Basin.


Run

Harvest

Imnaha




Total

Year

Ocean

Columbia R.

Return *

Strays

Return

1990

2


18

276




296

1991

0

8

142




150

1992

9

23

1,214




1,246

1993

8

0

973




981

1994

0

1

151

7

159

1995

0

1

190

4

195


1996

3

0

200

1

204

* = Compensation goal area.


      1. Escapement Goals

The escapement goal for this program is 3,210 adults annually (Nandor 1995).
1.10) Date Program started or is expected to start:

Lookingglass Hatchery and the Imnaha Acclimation Pond were both completed in 1982. The first releases of spring/summer chinook salmon for this program occurred in March 1984 (1982 brood).


1.11) Expected duration of program:

The Imnaha spring/summer chinook salmon stock 029 program is an ongoing project.


1.12) Watersheds targeted by program:

All hatchery-reared fish are released into the Imnaha River Subbasin (as defined by the Northwest Power Planning Council (NWPPC)).



SECTION 2.0 RELATIONSHIP OF PROGRAM TO OTHER MANAGEMENT OBJECTIVES


    1. List all existing cooperative agreements, memorandum of agreement, or other management plans or court orders under which program operates. Confirm HGMP consistency.




    1. Status of natural populations in target area.

      1. Geographic and temporal spawning distribution


Spring/summer chinook salmon historically spawned throughout the mainstem and major tributaries of the Imnaha River (Olsen et. al. 1994). Currently spawning is primarily in the mainstem (a 30-mile section from Freezeout Creek to the Blue Hole), Big Sheep Creek (an 11.5-mile section from Coyote Creek to 0.25 miles above Lick Creek), and Lick Creek (a 2.8-mile section from the confluence to the crossing of Forest Service Road 39) (Olsen et. al. 1994). Spawning has also been documented in South Fork Imnaha River (Nez Perce Tribe of Idaho et. al. 1990). Spawning ground surveys conducted in the Imnaha River in 1995 (August 25th to September 11th) and 1997 (August 20th to September 5th) documented new redds and live fish throughout these periods (Parker et. al. 1995, Parker and Keefe 1997). Migrating natural and hatchery adult spring/summer chinook salmon enter the Imnaha weir from July through September (Table 5). Spawning at Lookingglass hatchery occurs in August and September (Table 5).

      1. Annual spawning abundance for as many years as available



      1. Progeny to parent ratios, survival data by life stage, or other measures of productivity for as many brood years as available.




      1. Annual proportions of hatchery and natural fish on natural spawning grounds for as many years as possible.

The number of marked and unmarked spring chinook passed about the Imnaha weir since 1990 is provided in Table 1. For the period 1990 through 1999, the proportion of marked fish among the fish released from the Imnaha weir has averaged 43.6% and ranged from 24.0% to 65.1%. However, spring/summer chinook salmon do spawn in areas below the weir and the weir only traps about 52% of the run (AOP 1999). The proportion of marked carcasses recovered during 1994 through 1997 spawning ground surveys in the Imnaha River Basin is reported in Table 3.


Table 3: Origin of spring/summer chinook salmon carcasses, based on marking of hatchery fish, recovered during spawning ground surveys in the Imnaha River. Data from: 1994 and 1996 (Kinery 1999); 1995 (Parker et. al. 1995); and 1997 (Parker and Keefe 1997).


Run







Percent

Year

Marked

Unmarked

Marked

1994

24

30

44.4%

1995

5

23

17.9%

1996

8

60

11.8%

1997

109

59

64.9%


* = Compensation goal area.

      1. Status of natural population relative to critical and viable population thresholds.

2.3) Relationship to harvest objectives.

Three utilization objectives for Imnaha spring chinook salmon are identified in Nez Perce Tribe of Idaho et. al. (1990). These objectives include both hatchery and naturally produced fish. Fish from this program will also contribute to ocean and Columbia River harvest.


1. Establish tribal and sport harvest opportunity in the subbasin.

2. Provide opportunity for an annual non-selective tribal harvest of 350 fish.

3. Provide opportunity for an annual non-selective sport harvest of 350 fish.
2.4) Relationship to habitat protection and recovery strategies.

This hatchery program is part of a cooperative recovery strategy for naturally produced spring/summer chinook salmon in the Imnaha River.




    1. Ecological interactions

Potential ecological interactions with listed fish specifically caused by this hatchery program are unknown.

SECTION 3.0 WATER SOURCE:

SECTION 4.0 FACILITIES:

SECTION 5.0 ORIGIN AND IDENTITY OF BROODSTOCK

5.1) Source

Brood stock for the Imnaha River spring/summer chinook salmon program is collected from adult returns trapped at Imnaha weir and then transferred to Lookingglass hatchery for spawning. This includes both hatchery and naturally produced fish. The number of fish transferred to Lookingglass hatchery is reported in Table 1, and the number of fish spawned in Table 4.

5.2.1 History

Since the beginning of this program in 1982 only natural or hatchery produced Imnaha River spring/summer chinook salmon have been used for brood stock.


Table 4. Imnaha River spring/summer chinook salmon spawning data for the 1990 through 1999 brood years.


Brood Year

Marked Males Spawned

Marked Females Spawned

Unmarked Males Spawned

Unmarked Females Spawned

% Un-marked

Spawning Ratio F/M

Average Fecundity

Egg Take (1,000’s)

Fry Ponded (1,000’s)

Fingerling releases (1,000’s)

1990

35

49

39

25

43.2%

1.00


4,414

327

270

0

1991

11

24

27

15

54.5%

1.03

4,954

193

163

0

1992

46

86

69

28

42.4%

0.99

4,754

542

465

0

1993

134

139

58

54

29.1%

1.01

5,425


1,047

1,010

283

1994

15

13

6

9

34.9%

1.05

5,082

112

96

0

1995

16

9

30

6

59.0%

0.33

4,541

68

51

0

1996

15

7

37

17

71.1%

0.46

4,276

103

102

0


1997

54

50

8

7

12.6%

0.92

4,962

283

206

0

1998

59

33

31

28

39.1%

0.68

5,059

309

183

0


5.2.2 Annual Size

The program annual brood stock collection goal is 400 (Nez Perce Tribe of Idaho et. al. 1990). Actual collection goals are established each year through development of the annual operation plan. The green egg take goal for 1999 is 576,500 (AOP 1999). Actual number of males and females spawned is reported in Table 4.

5.2.3 Past and proposed level of natural fish in brood stock

Naturally spawning fish included in the brood stock, are reported in Table 4. The proportion of naturally produced fish (Unmarked) spawned has averaged 39.4% and ranged from 8.3% to 71.1% for the 1990 through 1999 brood years. Guidelines for the Imnaha weir call for retaining 2 of every 5 unmarked adults and 3 of every 5 Ad+CWT adults by age and sex, and 2 of every 5 unmarked jacks and Ad+CWT jacks trapped as brood stock (AOP 1999).

5.2.4 Genetic and ecological differences

There is currently no information about genetic and ecological differences between the hatchery stock and wild Imnaha fish. However, the brood stock is based on and annually incorporates locally adapted naturally produced fish, which should minimize differences.


5.2.5 Reasons for choosing

Brood stock is collected at Imnaha weir and incorporates naturally produced fish in order to maintain local adaptation and wild type characteristics.


5.3) Unknowns

SECTION 6.0 BROODSTOCK COLLECTION
6.1) Prioritized Goals:
6.2) Supporting Information:

      1. Proposed number of each sex

The program goal is to collect 400 fish for brood stock, and to spawn them in a ratio of 1 male to 1 female (Nez Perce Tribe of Idaho et. al. 1990). Actual collection designs are established each year in the annual operation plan. The collection design for the 1999 run year is described in section 6.2.3 (below).


      1. Life-history stage to be collected (e.g., eggs, adults, etc.)

Returning adults and jacks are collected at Imnaha trap. The fish are sorted based on the design below in section 6.2.3, and fish retained for brood stock are transported to Lookingglass hatchery.


      1. Collection or sampling design

All adults that enter the Imnaha trap are sorted by origin (marked vs. unmarked), sex and age. Fish retained for brood stock are 2 of every 5 unmarked adults and 3 of every 5 Ad+CWT adults by age and sex, and 2 of every 5 unmarked jacks and all Ad+CWT jacks (AOP 1999). Within the above criteria adults are selected randomly from the available fish for the brood stock. Brood stock fish are marked with an opercle punch and a jaw tag. Fish not retained for brood stock are marked with an opercle punch and released above the weir. Hatchery jacks may be placed above the weir, up to 10% of the males passed above the weir.

Table 5. Imnaha spring/summer chinook salmon program adult collection and spawning dates.


Run

Collection at Imnaha Weir

Spawning at Lookingglass Hatchery

Year

Beginning

Ending

Beginning

Ending

1990

9-Jul

18-Sep

23-Aug

18-Sep

1991

3-Jul

12-Sep

21-Aug

16-Sep

1992

18-Jun

8-Sep

18-Aug

8-Sep

1993

7-Jul

8-Sep

12-Aug

10-Sep

1994


27-Jun

13-Sep

24-Aug

8-Sep

1995

2-Aug

30-Aug

17-Aug

7-Sep

1996

23-Jul

4-Sep

14-Aug

12-Sep

1997

8-Jul

3-Sep

15-Aug

12-Sep

1998

11-Jul

8-Sep

5-Aug

14-Sep

1999

27-Jul

7-Sep

6-Aug

9-Sep




      1. Identity -

  1. Methods for identifying target populations (if more than one population may be present).

Naturally produced fish are identified based on lack of marks or tags. The Imnaha weir is in a location where only one wild population would be encountered.



  1. Methods for identifying hatchery origin fish from naturally spawned fish.

All hatchery fish released in the Imnaha basin from the 1990 brood year on have been marked with an adipose fin clip plus coded-wire tag (Ad+CWT). The only except is small numbers of fish which lose their marks.


      1. Holding -




      1. Disposition of Adults

Returning spring/summer chinook salmon collected at Imnaha weir are either retained for brood stock or released above the weir (see section 6.2.3 above). Hatchery fish are distinguished based on marks. Carcasses are either placed in to habitat for stream enrichment or sent to a landfill.
6.3) Unknowns:

SECTION 7.0 MATING


    1. Selection method

      1. Adult Selection -

Hatchery and natural origin fish are used for the brood stock. Fish are spawned based on a matrix determined each year. The specific matrix is based on the actual number of adults retained for brood each year (by origin, sex and age). The goal is to include all fish retained for brood stock in the spawning population. Cryopreservation of sperm may be used. Sperm from unmarked males will be cryopreserved for gene banking.


      1. Selection of Egg Take -

All females collected for brood stock, except pre-spawning mortalities, are spawned. Excess fish are not collected and thus selection or culling of eggs is not done. Disease monitoring may result in segregated rearing for fish health reasons but is not used to cull eggs.



    1. Males

Fish for this program are matrix spawned, determined annually based on brood stock collection. Overall sex ratios (including jacks) for the last 10 years are reported in Table 4.


    1. Fertilization




      1. Fertilization Scheme -




      1. Fish Health Procedures -

Fish health procedures are established in the annual operation plan. Specific plans for February 1999 through January 2000 are reported in AOP (1999).


    1. Cryopreserved gametes

Sperm are cryopreserved for gene banking and use in the matrix spawning.


    1. Unknowns



SECTION 8.0 REARING AND INCUBATION

SECTION 9.0 RELEASE
9.1) Life history stage, size, and age at release

Spring/summer chinook salmon smolts are released as yearlings from late March through early May after approximately 400 – 430 days of rearing in a hatchery environment. The target size at release for this program is 30.2 gm/fish (15 fish/lb) for direct releases. Acclimation groups compare two sizes at release 18.1 gm/fish (25 fish/lb) and 30.2 gm/fish (15 fish/lb). Actual size at release for the 1988 to 1997 brood years is reported in Table 6.

During the 1990’s there have been no releases of spring/summer chinook salmon unfed fry in the Imnaha Basin. The only non-smolt release was 283,046 1993 brood year fingerlings released in July 1994 at 4.6 gm/fish (98 fish/lb). These fingerling were excess to smolt production goals and were out-planted for natural rearing in the Imnaha Basin. Locations included in Big Sheep, Little Sheep, Cow, Freezeout, Horse, and Lightling Creeks and the main stem Imnaha River. These fish were 100% marked with an adipose fin clip. No unfed fry or fingerling releases are planned in the current Annual Operation Plan.

9.2) Life history stage, size, and age of natural fish of same species
9.3) Dates of release and release protocol

Releases consist of both acclimated and direct release groups. If smolt production numbers are below the program goal, releases at the Imnaha acclimation site take precedence over releases in Big Sheep and Lick Creeks, and acclimated releases take precedence over direct releases. Smolts have been released from late March through early May (Table 6). The current Annual Operation Plan calls for a direct release April 5th and 6th, and for a volitional acclimation release. The volitional release is to begin March 22nd with any remaining fish forced out April 15th.


9.4) Location(s) of release

Currently all smolts are released at the acclimation pond, located at the site of the Imnaha adult collection weir (about river mile 45.5). The program goal is to also release smolts in to Big Sheep Creek and Lick Creek. During the 1990’s the only release not at the acclimation site was 79,947 1988 brood year smolts released in to Big Sheep Creek in 1990 (Table 6).

9.5) Acclimation procedures

All smolts are reared at Lookingglass hatchery from hatching until release or transfer to the acclimation pond. Lookingglass hatchery transfers smolts to the acclimation pond as yearlings in March. The current Annual Operation Plan calls for a March 1st transfer with a volition release to begin March 22nd. Plans for the direct release group are to haul them April 5th and 6th from Lookingglass hatchery for direct release in to the Imnaha River near the acclimation site.

9.6) Number of fish released

Imnaha River spring/summer chinook salmon releases for the last 10 years are reported in Table 6. Anticipated actual releases in 2000 (1998 brood year) are 180,000 smolts (AOP 1999). The program goal is a 490,000 smolt release.


Table 6. Releases of spring/summer chinook salmon in the Imnaha River Basin for the last 10 years, 1988 through 1997 brood years (1990 – 1999 release years).

Brood Year

Release Type

Release Dates

Location

Number Released

Kg Released

gm/fish

1988

Acclimated

03/31/90

03/31/90

Imnaha Accl. Pond

249,793

7,395

29.6




Direct

04/02/90


04/04/90

Imnaha Accl. Pond

114,722

2,738

23.9




Direct

04/02/90

04/02/90

Big Sheep Creek

79,947

1,973

24.7

1989

Acclimated

03/22/91

04/09/91

Imnaha Accl. Pond

398,909

9,622

24.1

1990

Acclimated

03/30/92

03/30/92

Imnaha Accl. Pond

175,398

5,547

31.6





Direct

03/30/92

03/30/92

Imnaha Accl. Pond

87,188

1,832

21.0

1991

Acclimated

04/12/93

04/12/93

Imnaha Accl. Pond

157,659

4,089

25.9

1992

Acclimated

04/11/94

04/11/94

Imnaha Accl. Pond

271,353

6,810

25.1




Direct

04/11/94

04/11/94

Imnaha Accl. Pond


167,274

3,717

22.2

1993

Acclimated

03/28/95

05/05/95

Imnaha Accl. Pond

445,670

11,091

24.9




Direct

03/28/95

04/24/95

Imnaha Accl. Pond

144,399

3,123

21.6

1994

Acclimated

04/02/96

04/02/96

Imnaha Accl. Pond

91,240

2,242

24.6

1995


Acclimated

04/08/97

04/08/97

Imnaha Accl. Pond

50,911

1,360

26.7

1996

Acclimated

04/07/98

04/07/98

Imnaha Accl. Pond

93,108

2,005

21.5

1997

Acclimated

04/16/99

04/16/99

Imnaha Accl. Pond

184,725

4,528

24.5




Direct

04/05/99

04/05/99

Imnaha Accl. Pond

10,242


320

31.3


9.7) Marks used to identify hatchery adults

All juvenile spring/summer chinook salmon released for this program will be Ad+CWT marked. In addition some fish will be marked with Passive Integrated Transponders (PIT tags). The number of fish to be PIT tagged will be determined in the Annual Operation Plan. The 1999 AOP calls for 23,499 Imnaha spring/summer chinook salmon to be PIT tagged, this includes a sample from each rearing pond at Lookingglass hatchery.




    1. Unknowns

SECTION 1.0. GENERAL PROGRAM DESCRIPTION



1.0) Name of Program
Imnaha Subbasin Hatchery Summer Steelhead Program (Lower Snake River Compensation Plan)
1.1) Population (or stock) and species

Oncorhynchus mykiss, summer steelhead (stock 029)


    1. Responsible organization and individual

ODFW Portland Staff:

Name (and Title): Trent Stickell

Organization: Oregon Department of Fish and Wildlife

Address: 2501 SW First, Portland, OR 97207

Telephone: 503-827-5252

Fax: 503-872-5632

Email: Trent.W.Stickell@state.or.us

ODFW Regional Staff:

Name (and Title): Bruce Eddy, Grande Ronde Watershed District Manager

Organization: Oregon Department of Fish and Wildlife

Address: 107 20th Street, La Grande, OR 97850

Telephone: 541-963-2138

Fax: 541-963-6670

Email: bruce.r.eddy@state.or.us

Other organizations involved:

US Fish and Wildlife Service

Confederated Tribes of the Umatilla Indian Reservation

Nez Perce Tribe (NPT)




    1. Location(s) of hatchery and associated facilities:

  • Adult Collection, Holding and Spawning:

Adult summer steelhead are collected, held and spawned at Little Sheep Creek acclimation facility. This facility is located along Little Sheep Creek, a tributary to the Imnaha River and consists of one acclimation pond and one adult holding pond.


  • Rearing (from green-egg to eyed-egg):

After fish are spawned, green eggs are transferred to Wallowa Hatchery for eye-up. Wallowa Hatchery is located along Spring Creek, a secondary tributary to the Wallowa River, one mile west of Enterprise, Oregon. Site elevation is 3,700 feet above sea level (IHOT, 1995).


  • Incubation and Rearing (from eyed-egg to smolt):

After eye-up, fish are transferred to and reared at Irrigon Hatchery. Irrigon Hatchery is located along the south bank of the Columbia River, above John Day Dam, near Irrigon, Oregon. Site elevation is 277 feet above sea level.


  • Acclimation to release:

Currently, 330,000 smolts are scheduled to be transferred from Irrigon Hatchery in March and April and acclimated at Little Sheep Creek facility for at least three weeks, before being released into Little Sheep Creek.

1.4) Type of program:

Imnaha River summer steelhead stock is managed to compensate for a portion of the summer steelhead losses caused by the construction and operation of four lower Snake River dams and to support sports and tribal fisheries.


1.5) Purpose of program:


  1. Compensate for summer steelhead abundance lost due to the construction and operation of Ice Harbor, Lower Granite, Little Goose and Lower Monumental dams.

  2. Improve sport harvest, while minimizing impacts on naturally produced steelhead in the Imnaha River Basin (Salmon and Steelhead Stock Summaries for the Grande Ronde River Basin, 1994).

  3. Broodstock maintenance to perpetuate program goals.




    1. Specific performance objectives(s) of program: To be addressed later.

    2. List of performance Indicators designated by “benefits” and “risks”: To be addressed later.




    1. Expected size of program:


1.8.1 Expected Releases

Current ODFW production goals for the Imnaha River subbasin summer steelhead program are:



  • Release 230,000 marked smolts at 5.0/lb into Little Sheep Creek in April (Lower Snake Program Annual Operation Plan (AOP), 1999).

  • Release 100,000 marked smolts at 5.0/lb into Big Sheep Creek in May (AOP, 1999).


Adult fish produced and harvested

The number of adults returning to Little Sheep Creek facility since 1990 is presented in Table 1.


Table 1. Adults returned to Little Sheep Creek and number of adults spawned, 1990 to 1998.













Adults Passed Above the Trap




Adults Spawned




Return

Year

Origin

Adults Counted

Male

Female

Percent Wild

Male

Female

Percent Wild

1990

Wild

57

7

11




11

23







Hatchery

924

293

305

2.9


146

156

10.1

1991

Wild

29

6

8




4

9







Hatchery

366

23

18

25.5

129

121

4.9

1992

Wild

128

37 1/

38




27 1/

33







Hatchery

661

52

57

40.8


188

144

15.3

1993

Wild

99

17

60




4

18







Hatchery

1173

60

17

50.0

154

116

7.5

1994

Wild

53

21

20




12

8







Hatchery

141

19

17

53.2

10


94

16.4

1995

Wild

17

2

10




1

4







Hatchery

278

28

6

26.1

101

95

2.5

1996

Wild

48

22 3/

19




6

6







Hatchery

443 /4

36

32

34.0

108

153

4.4


1997

Wild

29

9

15




2

2







Hatchery

937

32

21

31.2

182

182

1.1

1998

Wild

33

7

18




2

6







Hatchery

686

44

72

17.7

192 5/

340

1.5


1/ Includes 12 wild males spawned and released

3/ Includes 6 wild males spawned and released

4/ Includes 22 males and 46 females outplanted to local ponds.

5/ Produced 1,598,340 green eggs.
The 1989 to 1993 summer steelhead (stock 029) brood reared at Irrigon Hatchery and released into Little Sheep Creek survived at an average rate of 0.49% and were caught primarily in tribal gillnet (Columbia Basin) and other freshwater fisheries (Lewis, 1999). The harvest rate of summer steelhead stock 029, for run years 1991 through 1996 averaged 110 per year (ODFW RFMEP, 1997).




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