Relationships between resident and anadromous O. mykiss in Cedar River, WA: Anne Marshall WA Dept of...

Relationships between resident and anadromous O. mykiss in

Cedar River, WA:

Anne Marshall WA Dept of Fish and Wildlife

improving the chances for steelhead recovery, or

Current research project-

“Genetic relationships among anadromous and non-anadromous O. mykiss in Cedar River and Lake Washington: implications for steelhead recovery planning”

Principal investigators- Anne Marshall, Maureen Small, and Steve Foley; WDFW

Funded in part by Seattle Public Utilities, Landsburg Mitigation Agreement

Motivation for our study-

Steelhead population was declining but rainbow trout appeared to be abundant in Cedar River

Previous genetic results for O. mykiss parr above and below the dam

Adult and juvenile fish passage at Landsburg Dam was to be completed by 2003, opening up ~18 miles of former steelhead habitat

Managers’ needs –

Concerns about extinction risks and obligation to pursue mitigation for dam impacts in Cedar River. . .

What in-basin factors were limiting the success of steelhead?

Should artificial production of steelhead be pursued?

Would trout above the dam become anadromous once passage was open?

Our premise –

Understanding relationships between the co-occurring life-history forms was critical for effective management of steelhead

Were steelhead producing the majority of resident fish?

Were resident trout of non-local origin and were they creating impacts through interbreeding and competition?

If so, were resident fish contributing to smolt production?

Research Goal –

“Understand genetic population structure of

Cedar River and Lake Washington O. mykiss

so that managers can design and implement

effective strategies to conserve and recover

native steelhead and rainbow trout resources”

Research objectives –

Determine genetic relationships between adult steelhead and adult resident O. mykiss in Cedar R. & Lake WA

Determine genetic relationships between smolts and potential parent groups

Investigate in-depth the genetic relationships between above and below dam populations

Estimate extent of O. clarki and O. mykiss hybridization

Estimate effective population size if appropriate

Background information and environment –

Special features for this coastal steelhead population –

• Engineered river and migrational route

• Large lake basin in migrational route

• Large sympatric sockeye population

• Relatively large and apparently adfluvial sympatric cutthroat population

• Within largest metropolitan area of WA

Cedar River watershed, Puget Sound, WA

Map from City of Seattle, Cedar R. Habitat Conservation Plan web site

Physical, migrational barriers for Cedar River steelhead

Landsburg Dam, RM 21

Ballard Locks, 1 mi from Puget Sound (ship canal entrance to Lake Washington)

Bridge Trolls

0100200300400500600700800900

1000

83-8

4

85-8

6

87-8

8

89-9

0

91-9

2

93-9

4

95-9

6

97-9

8

99-0

0

Cedar River wild steelhead annual escapement estimates

Lake Washington System and Cedar River Four Year Average

Escapements

0

500

1000

1500

20008

3-8

6

84

-87

85

-88

86

-89

87

-90

88

-91

89

-92

90

-93

91

-94

92

-95

93

-96

94

-97

95

-98

96

-99

97

-00

98

-01

Four year period

Ave

rag

e es

cap

emen

t

System average Cedar average

Cedar River and other O. mykiss populations - plot of genetic distances based on allozyme data from S. Phelps and B. Baker

(Cedar River above Landsburg Dam)

(Chester Morse Reservoir)

(Hatchery exotic rainbow stock)

Methods

Fish capture – two year cycle with 50-fish goal per site per year: fish ladder trap at Locks; angling for adults (>30 cm); screw trap for smolts

Fin clips and scales

Genetic:

Sampling:

Microsatellite DNA markers; nuclear species markers; possibly mitochondrial DNA markers

Genetic population statistics; differentiation metrics; assignment and admixture tests

Populations or groups included in study plan -

1. Steelhead at Ballard Locks

2. Steelhead in Cedar River

3. Cedar R. resident O. mykiss below Landsburg Dam

4. Cedar R. resident O. mykiss above Landsburg Dam

5. Chester Morse Lake O. mykiss

6. Adult O. mykiss in Lake Washington

7. Cedar R. O. mykiss smolts - lower river trap

8. Wild Green River steelhead

9. Hatchery steelhead stock in Green River

10. Resident O. mykiss from Green River Basin

11. Hatchery exotic-origin rainbow trout stocks

12. Cedar R./Lake Washington cutthroat trout (O. clarki)

Sampling results to date -

1. Steelhead at Ballard Locks N=56

(1 from 2003, rest from 1997, ‘98 & ’99 scale samples)

3. Cedar R. resident O. mykiss below Landsburg Dam N=53

4. Cedar R. resident O. mykiss above Landsburg Dam N=50

6. Adult O. mykiss in Lake Washington N=4

7. Cedar R. O. mykiss smolts - lower river trap N=17

8. Wild Green River steelhead N=122

12. Cedar R./Lake Washington O. clarki N=36

(from 2002 and 2003)

(and 10 potential O. mykiss/O. clarki hybrids)

Existing samples included in preliminary genetic analyses -

Hatchery winter-run steelhead (Chambers Creek stock) from Puyallup River Basin – current substitute for hatchery stock sample (9.) from Green River

11. Hatchery exotic-origin rainbow trout stocks -

South Tacoma Hatchery, Spokane Hatchery, Goldendale Hatchery, & Eell Springs Hatchery – all are California-origin stocks

Resident O. mykiss sampled in lower Cedar River in May 2003 for genetic analysis

More sampled fish…

O. clarki from lower Cedar River, where potential inter-specific hybrids (based on phenotype) were also sampled.

Pop./Site Ave. Length cm (N)

Ave. Age (range)

Steelhead- Ballard locks 72.7 (53)

[next Table] (3 – 6)

Resident O. mykiss- lower Cedar

35.7 (53) 3.6 (2 – 8)

Resident O. mykiss- upper Cedar

24.3 (50) 2.0 (1 – 5)

Smolts 18.7 (17)

Sampled Fish Size & Age

Age Class W1.1+ W1.2+ 2.1+ 2.2+ 2.3+ 3.1+ 3.2+

% 14 7 48 23 2 4 2

Steelhead Ages – Ballard Locks (N=56)

30 females and 26 males

Microsatellite DNA loci used for preliminary analyses to date -

Oki-10 Ots-1 Omm-1128

One-2 Ots-3M Omm-1130

One-18 Ots-100 Omm-1138A

One-102 Ots-103 Omm-1138B

One-114 Omy-325 Sco-103

One-101 Omy-1001 Sco-110

One-108 Omy-1011 Ogo-3

Ongoing -

Statistical analyses of microsatellite genetic data

Hybrids analysis with nuclear markers

Assignment and mixture analysis for smolts and other samples

Sampling for year 2 to begin in March or April 2004

Progress report in June 2004