Todd Seamons and Tom Quinn University of Washington School of Aquatic and Fishery Sciences Individual lifetime reproductive success of repeat spawners.
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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 Townsend
Discovery B
ayBarrier waterfall
~5 km
Study site: Snow Creek
Oncorhynchus mykiss
Photo: Thom Johnson
Snow Creek
Strait of Juan De Fuca
Port Townsend
Discovery B
ay
Permanent weir - WDFW
~5 km
Snow Creek
Strait of Juan De Fuca
Port Townsend
Discovery B
ay
No hatchery*
~5 km
Snow Creek
Strait of Juan De Fuca
Port Townsend
Discovery B
ay
~5 km
Snow Creek
Strait of Juan De Fuca
Port Townsend
Discovery B
ay
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
1401
98
2
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
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 years
N (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 years
N (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
pro
po
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
rag
e #
off
spri
ng
± 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
rag
e #
off
spri
ng
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
rag
e #
off
spri
ng
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
rag
e #
off
spri
ng
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)
Pro
po
rtio
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
Re
lati
ve
re
pro
du
ctiv
e s
ucc
ess
smaller bigger
Relative length
P < 0.01
r2 = 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
ela
tiv
e r
ep
rod
uct
ive
su
cce
ss
smaller bigger
Relative length
P < 0.01
r2 = 0.01
Consistent repeat spawning rates
• across Washington rivers
River Run % x 1 % x 2 % x 3
Skagit Winter 92 7 1
Snohomish Winter 92 6 1
Green Winter 93 7
Puyallup Winter 89 10
Nisqually Winter 93 6 1
Quillayute Winter 91 7 1
Cowlitz Winter 96 4
Kalama Winter 93 6
Kalama Summer 94 6
Source: Busby et al. 1996
Snow Creek rates are about the same
River Run % x 1 % x 2 % x 3
Skagit Winter 92 7 1
Snohomish Winter 92 6 1
Green Winter 93 7
Puyallup Winter 89 10
Nisqually Winter 93 6 1
Quillayute Winter 91 7 1
Cowlitz Winter 96 4
Kalama Winter 93 6
Kalama Summer 94 6
Snow 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
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
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
Se
x 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
Fre
qu
ency
Males
Females
Uneven distribution of adult offspring among parents
average = 0.91
σ2 / μ2 = 2.67
Pro
po
rtio
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
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Mother Father
1998
1999
2000
Mothers Fathers
Mothers Fathers
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0
Pro
po
rtio
n
Pro
po
rtio
n
mature male parr
~30%
~30%
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