Post on 18-Mar-2016
description
Todd Seamons and Tom QuinnUniversity of Washington
School of Aquatic and Fishery Sciences
Individual lifetime reproductive success of repeat spawners vs. one-
time spawners
Hypotheses• Repeat spawners will have more
offspring than one-time spawners– In terms of lifetime reproductive success
Hypotheses• Repeat spawners will have more
offspring than one-time spawners– In terms of lifetime reproductive success
• But repeat spawning fish don’t just age between brood years, they also grow
Female choiceDominance
Body Size
Longevity
MalesReproductive success
Hypothesized size advantages for repeat spawners
Egg SizeFecundity
Body Size
Redd Quality
FemalesReproductive success
Hypothesized size advantages for repeat spawners
Other advantages?
• Prior knowledge/experience?– Females
• Best redd sites
– Males• Spawning territories?
Hypotheses• Repeat spawners will have more
offspring than one-time spawners
• Repeat spawners will produce more than twice the average number of offspring of one-time spawners
Hypotheses• Repeat spawners will have more
offspring than one-time spawners
• Repeat spawners will produce more than twice the average number of offspring of one-time spawners
• Repeat spawners will produce more offspring the second time they spawn than the first time
Snow Creek
Strait of Juan De Fuca
Port TownsendDiscovery BayBarrier waterfall
~5 km
Study site: Snow Creek
Oncorhynchus mykiss
Photo: Thom Johnson
Snow Creek
Strait of Juan De Fuca
Port TownsendDiscovery Bay
Permanent weir - WDFW
~5 km
Snow Creek
Strait of Juan De Fuca
Port TownsendDiscovery Bay
No hatchery*
~5 km
Snow Creek
Strait of Juan De Fuca
Port TownsendDiscovery Bay
~5 km
Snow Creek
Strait of Juan De Fuca
Port TownsendDiscovery Bay
No fishing!
~5 km
Adults trapped and sampled at the weir
Sampling
• Date• Sex• Fin clip (DNA)• Fork Length (mm)• Scales (DNA, age – Jon Sneva, WDFW)
6
143
0
20
40
60
80
100
120
14019
8219
8319
8419
8519
8619
8719
8819
8919
9019
9119
9219
9319
9419
9519
9619
9719
9819
9920
00
Brood Year
Total number of adults returning to Snow Creek in 19 brood years
Brood Year
N (M
+F)
1986 1987 1988 2004Parental brood year
1982
1983
1984
Adult offspring sample year
Directly enumerate number of adult offspring returning to spawn
2000
1989
19 parental brood yearsN (parents + adult offspring) = 1094
1986 1987 1988 2004Parental brood year
1982
1983
1984
Adult offspring sample year
Directly enumerate number of adult offspring returning to spawn
2000
1989
19 parental brood yearsN (parents + adult offspring) = 1094
• Scales • Fin Clip
1986 1987 1988 2004Parental brood year
1982
1983
1984
Adult offspring sample year
Directly enumerate number of adult offspring returning to spawn
2000
1989
Genetically match parents to returning adult offspring
How were repeat spawners identified?
• Healed opercle scar
• Healed opercle scar
• Scales– Spawn check
Spawn check
Photo: Michael Dauer
How were repeat spawners identified?
• Healed opercle scar
• Scales– Spawn check
Spawn check
Photo: Michael Dauer
How were repeat spawners identified?
• Healed opercle scar
• Scales– Spawn check
• DNA
Female - 1988
Female - 1989
How were repeat spawners identified?
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Females Males
More females survive to kelt than malesA
vera
ge p
ropo
rtio
n Range: 56-91%
64% overall survival to kelt (11 years of data)
54%
74%
Range: 31-84%
Snow Creek repeat spawner growth
• Growth– Female average = 42 mm (n = 16)– Male average = 71 mm (n = 3)
• Fecundity– +350 – 450 eggs – A little over 10% increase in fecundity
0.0694033*[Length]^1.66088 – Thom Johnson personal comm.
Hypotheses• Repeat spawners will have more adult
offspring than one-time spawners
• Repeat spawners will produce more than twice the average number of adult offspring of one-time spawners
Repeat spawning females have only twice the number of adult offspring as single-time spawners
0.0
0.5
1.0
1.5
2.0
2.5
Single Repeat
0.9 offspring / female
1.8 offspring / female
Ave
rage
# o
ffspr
ing
± 1
SE
Spawner type
N=380 N=54
t-test, p=0.001
Repeat spawning males have a little more than twice the number of adult offspring as single-time spawners
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Single Repeat
0.5 offspring / male
1.2 offspring / male
Ave
rage
# o
ffspr
ing
Spawner type
N=383 N=19
± 1
SE
t-test, p=0.05
Hypotheses• Repeat spawners will have more adult
offspring than one-time spawners
• Repeat spawners will produce more than twice the average number of adult offspring of one-time spawners
• Repeat spawners will produce more adult offspring the second time they spawn than the first time
Repeat spawning females produced slightly more adult offspring their second spawning
0.0
0.2
0.4
0.6
0.8
1.0
1.2
First Second
0.8 offspring / female0.9 offspring / female
Ave
rage
# o
ffspr
ing
Spawning Year
N=54 N=54
± 1
SE
Not significantly different
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
First Second
Repeat spawning males produced all of their adult offspring their second spawning
0 offspring / male
1.2 offspring / male
Ave
rage
# o
ffspr
ing
Spawning Year
N=19 N=19
± 1
SE
Summary - males• Repeat spawning male LRS = x2.4 one-
time spawners• First time spawning males produce no
adult offspring
• Life-history trade off for males?– sacrifice present reproduction for future
Summary - females• Repeat spawning female LRS = x2 one-
time spawners• In any one year, a repeat spawning
female is only as good as a one-time spawning female
• No obvious trade-off for females
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
275
320
365
410
455
500
545
590
635
680
725
770
815
860
Length (mm)
Prop
ortio
n Not all repeat spawners are big
Repeat spawners @ 2nd time spawningAll adults
0
5
10
15
20
25
30
35
40
-5 -4 -3 -2 -1 0 1 2 3 4
Rel
ativ
e re
prod
uctiv
e su
cces
s
smaller biggerRelative length
P < 0.01r2 = 0.01
Bigger is better for males (but not much)
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
-6.0 -4.0 -2.0 0.0 2.0 4.0 6.0
Bigger is better for females (but not much)R
elat
ive
repr
oduc
tive
succ
ess
smaller biggerRelative length
P < 0.01r2 = 0.01
Consistent repeat spawning rates• across Washington rivers
River Run % x 1 % x 2 % x 3Skagit Winter 92 7 1Snohomish Winter 92 6 1Green Winter 93 7Puyallup Winter 89 10Nisqually Winter 93 6 1Quillayute Winter 91 7 1Cowlitz Winter 96 4Kalama Winter 93 6Kalama Summer 94 6
Source: Busby et al. 1996
Snow Creek rates are about the same
River Run % x 1 % x 2 % x 3Skagit Winter 92 7 1Snohomish Winter 92 6 1Green Winter 93 7Puyallup Winter 89 10Nisqually Winter 93 6 1Quillayute Winter 91 7 1Cowlitz Winter 96 4Kalama Winter 93 6Kalama Summer 94 6Snow Creek Winter 88 10 2
Source: Busby et al. 1996
• but much smaller population
• Would removal = fewer in the future?
Probably NOT
• Genetic component of repeat spawning ≈ 0
• Repeat spawning = almost all environmental– Spawning conditions– Flow at outmigration– Migration distance– Ocean conditions upon arrival– Ocean conditions for the next year
Is it important to keep repeat spawners in the population?
Is it important to keep repeat spawners in the population?
• Repeat spawning = Overlapping generations– Slow the rate of loss of genetic diversity
• Important for population recovery– Increased rate of recovery for small
populations
Many many many many thanks…
• Thom Johnson WDFW• Randy Cooper WDFW• Cheri Scalf WDFW• Jon Sneva WDFW• Many volunteers
Many Thanks…• In the field
– Jen McLean– Caryn Abrey– Ray Timm– Josh Latterell– Greg Mackey– Ian Stewart– Erin McClelland– Chris Boatright– Et al.
• MMBL– Sofia– Jen McLean– Mike Canino– Tatiana Rynearson– Patrick O’Reilly– Rolf Ream– Pam Jensen– Brent Vadopalas– Ingrid Spies– Sara Feser– Jennifer Cabbarus– Anny Soon– Ann Riddle– Willy Eldridge– Erin McClelland– Et al.
• Funding– National Science Foundation– H. Mason Keeler Endowment
• Data Analysis– Kevin Brinck– Stephanie Carlson
• The Quinn Group– Jen McLean– Caryn Abrey– Bobette Dickerson– Stephanie Carlson– Richie Rich– Et al.
6
143
0
20
40
60
80
100
120
140
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Brood Year
N
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Total number and sex ratio of adults returning to Snow Creek in 19 brood years
Brood Year
N (M
+F)
2:1
1.5:1
1:1
1:1.5
1:2
1:2.5
3:1
2.5:1
Sex ratio+F +M
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0 1 2 3 4 5 6 7 8
Freq
uenc
y
MalesFemales
Uneven distribution of adult offspring among parents
average = 0.91
σ2 / μ2 = 2.67
Prop
ortio
n
19 brood years
# adult offspring per parent
average = 0.52
σ2 / μ2 = 4.59
Embryos
Juveniles
Smolts
AdultsOcean
Freshwater
Mature male parr
More mothers assigned
than fathers
3 brood years
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Mom Dad
19 brood years
00.10.20.30.40.50.60.7
Mother Father
199819992000
Mothers Fathers
Mothers Fathers
0.700.600.500.400.300.200.10
0
0.700.600.500.400.300.200.10
0
Prop
ortio
n
Prop
ortio
n
mature male parr
~30%
~30%