SLIDE 1 A Comparison of the Performance of Summer Steelhead Smolts Released at Two Sizes From Wallowa Hatchery
This work was funded by the United States Fish and Wildlife Service through the Lower Snake River Compensation Program
Oregon Department of Fish and Wildlife 203 Badgley Hall Eastern Oregon University
Lance Clarke, Mike Flesher and Rich Carmichael
SLIDE 2 LSR SRCP P Ob Obje jecti ctives
r each des esignate ted s sto tock, es establish an n ann nnual s sup upply of
h capable o e of m meet eting egg gg-tak take e goals. s.
a to tota tal retu eturn o
summer er steel elhead ead in O Ore regon that at meet eets compen ensati tion g goals.
esta tablish sport a t and t tribal al fisheri eries es.
e the impacts acts of t the program am on residen ent t stocks of g game e fish. h.
SLIDE 3 Wh Why a a Siz ize a at Release S Study dy?
- 1. Older studies were with smaller fish (5.5 – 35 fish/lb.).
- 3. Address potential interactions with wild fish from
release size.
- 2. Regional, stock, and hatchery specific factors
have produced variable results in past size at release studies.
SLIDE 4 Size a e at R Relea ease se S Study O y Objec ectives es
ts grown to to tar target sizes of 5 5 fish/lb. (90 g (90 g) ) or r 4 4 fish/lb. (113 (113 g). ).
are e juven enile e migrati tion c charac acteri eristi tics cs a and passage i indices ces at Lower G er Granite D te Dam.
ermine e differ eren ences ces i in c catch contri tributi tion p pattern erns a and smolt-to to- adult s t survival al.
e co compositi tion at t retu eturn.
sess ss producti ction effecti ectiven enes ess by c compari aring perf rform rman ance ce measur ures such h as adults prod
uced per thous usand nd pound nds of smolts ts releas eased ed.
stra ray rat rates.
SLIDE 5 The Grande Ronde River Basin and Associated Hatchery Facilities
Washington Oregon
LOWER GRANITE DAM
N
20 20 40 Kilometers
Wallow
a Hatc tche hery Irri rrigon Hatc tche hery
SLIDE 6
Wallowa H a Hatchery a y and Adult Ladder
SLIDE 7
Irrigon Fish Hatchery
SLIDE 8
Wallo llowa H Hatchery A Acclim limatio tion P Pond
SLIDE 9 Relea ease se Data S a Summar ary
Brood year Target size (fish/lb) Release dates Number Coded-wire tagged Number branded 1985 5 5 May 86 52,433 29,985 4 55,002 29,749 1986 5 25-27 Apr 87 46,571 29,132 4 50,019 29,123 1988 5 24 Apr 89 53,448 49,957 4 53,021 49,988 1989 5 19 Apr 90 53,097 50,329 4 52,820 49,711 1990 5 22 Apr 91 57,553 41,089 4 53,886 40,938
Wallow
a Stock S Steel eelhead head S Size a at R Relea ease S e Study
SLIDE 10 Relea ease se Data S a Summar ary
Brood year Target size (fish/lb) Mean weight fish/lb (g) Mean Length (mm) 1985 5 5.4 (84.0) 204 4 3.9 (115.2) 224 1986 5 4.7 (96.9) 214 4 3.6 (124.5) 231 1988 5 5.3 (86.4) 203 4 3.8 (118.2) 223 1989 5 5.3 (85.9) 202 4 4.2 (108.0) 218 1990 5 4.5 (101.0) 212 4 3.9 (116.6) 222
Wallow
a Stock S Steel eelhead head S Size a at R Relea ease S e Study
SLIDE 11 Length Freq equen ency D y Distribution ( (198 989)
Wallow
a Stock S Steel eelhead head S Size a at R Relea ease S e Study
5 10 15 20 25 30 150 175 200 225 250 275
For
Length (m (mm)
5.3 Fish/lb 3.8 Fish/lb
Nu Numb mber o
SLIDE 12 Smol Smolt Passa ssage e at L Lower er G Granite D Dam
No significant difference P = 0.972
10 20 30 40 50 1985 1986 1988 1989 1990
Percent of Release Br Brood Y Year ear
5 Fish/lb 4 Fish/lb
SLIDE 13 Mig Migratio ion T Tim imin ing to Lower er Gr Granite ite D Dam
5 Fish/lb 4 Fish/lb
Percent of Total to Lower Granite Dam
10 20 30 40 50
1989
10 20 30 40 50
1990
10 20 30 40 50 15 20 25 30 35 Week eek o
the e Year ear
1991
10,173 10,884 14,900 12,078 18,030 18,141
SLIDE 14 Smol Smolt to
ult Sur Survival
42% difference, significant, P = 0.006
554 1,063 540 483 105 224 627 891 680 1,053
5 Fish/lb 4 Fish/lb
0.0 0.5 1.0 1.5 2.0 1985 1986 1988 1989 1990
Br Brood Y Year ear Perce cent R nt Reco cover ered ed
SLIDE 15 Stray R y Rate Index
, n = 199
199 , n = = 329 329
5 10 15 20 25 1985 1986 1988 1989 1990
- No. Strays / Total Recoveries
Br Brood Y Year ear
66% difference, significant, P = 0.004
5 Fish/lb 4 Fish/lb
SLIDE 16 Adul ult Pr Prod
Comp
12.8% difference, not significant, P = 0.179
20 40 60 80 100
1985 1986 1988 1989 1990 Adults Prodced / 1,000 lbs smolts
Br Brood Y Year ear
5 Fish/lb 4 Fish/lb
SLIDE 17
Ca Catc tch and E Escapem ement Di Distr tribution f for 1 198 989 Brood
Catch
5 fish/lb (n = 627) % of total 4 fish/lb (n = 891) % of total Columbia River: Net 28.2 28.5 Columbia River: Sport 13.1 9.3 Deschutes River 5.3 7.1 Snake River and Tributaries 24.9 29.6 Grande Ronde River 10.7 8.1 Ocean 0.0 0.4 Catch Total 82.2 83.0
Escapement
Deschutes Trap 4.9 3.9 Wallowa Hatchery 12.9 13.1 Escapement Total 17.8 17.0
SLIDE 18
Age Compositon of Returns to Wallowa Hatchery
5 Fish per Pound 4 Fish per Pound Brood Years 1985-1990 (excluding 1987)
Age 4 (2-Ocean) 39.6% Age 3 (1-Ocean) 60.4% Age 3 (1-Ocean) 64.4% Age 4 (2-Ocean) 35.6%
N = 5,968 fish No significant difference P = 0.183
SLIDE 19
Similar SAS and SRI Patterns, Why?
1. Inconsistent tag sampling rate among years. 2. Older age at return when SAS is higher. 3. When survival is high, smolts that may be predisposed to stray survive at a higher rate. 4. Residualism-varying rates of residualism would influence the SAS calculation and could vary the percentage of outmigrating smolts that are inclined to stray as adults. 5. Adults might stray more when run sizes are large. 6. A spurious correlation. Some Hypotheses
SLIDE 20
Summa Summary
1. 1. There e was n no consisten tent t trend i in smolt passage e indices ces or migrati tion timing. 2. 2. Smolt-to to-ad adult survival al was g grea eater i ter in f four o r of five y e year ars a and w was significan cantly b better er over er the five-year ear period for r the fish r releas eased ed a at 4 fish/lb compar ared ed to 5 fish/lb. 3. 3. Number er of adults ts produced ced p per 1,000 l 00 lbs of smolts ts releas eased ed was as grea eater er in four r of five e year ars but w was as n not s significan cantl tly better er over r th the f e five-year p ear peri riod. 4. 4. Large e sized ed smolts ts strayed ed a at a a higher r er rate e in every ery year ar. 5. 5. Catch a and escapem emen ent t distri ributi tion was s similar ar for r all brood year ars. 6. 6. There e was n no differ eren ence ce in mean age c compositi tion of r return rns.
SLIDE 21 Othe her C Cons
Total al Sm Smolt lt Producti ction: A releas ease s e size c e change e to 4 fish/lb mean eans fewer er smolts ts needed ed to reac ach adult t producti ction g goal
000 smolts ts @ 4 4 fish/lb. = 1,136, 136,000 000 smolts ts @ 5 fish/ h/lb. Brood
eeds can can be e red educed . . Residual alism: Fewer er smal all fish, w which h have e been shown to residual alize, will be releas eased
er, fas aster g er growth r rates es a at 4 fish/lb. may produce ce more e early maturi ring residual al m males es. The effect ect of size a e at releas ease e on survival al may be m mediated ted by the leng ngth of
n to
he oc
