ices annual symposium, bergen, 14 may 2004
DESCRIPTION
Non-additive effects of environmental variables on the recruitment of walleye pollock ( Theragra chalcogramma ) in the Gulf of Alaska. Does the intensity of density-dependent control change over contrasting environmental phases?. - PowerPoint PPT PresentationTRANSCRIPT
L. CiannelliL. Ciannelli - NOAA, Seattle - NOAA, SeattleK. BaileyK. Bailey - NOAA, Seattle - NOAA, Seattle N.C. StensethN.C. Stenseth – CEES, University of Oslo, Norway – CEES, University of Oslo, NorwayK.S. ChanK.S. Chan - University of Iowa - University of IowaA. BelgranoA. Belgrano - University of New Mexico - University of New Mexico
ICES annual symposium, Bergen, 14 May 2004
Non-additive effects of environmental Non-additive effects of environmental variables on the recruitment of walleye pollock variables on the recruitment of walleye pollock ((Theragra chalcogrammaTheragra chalcogramma) in the Gulf of ) in the Gulf of AlaskaAlaska
Does the intensity of density-dependent control change over contrasting environmental phases?
Pollock early life cyclePollock early life cycle
3
ACC
-Hypothesis: non-additive effect of DI and demographic variables on pre-recruitment survival: variable levels of DD
AnalysisAnalysis
tj
jtj
at
at EgXfbS )()(0GAM: additive
tkt
k
atk
j
jtj
at
at EXsEgXfbS )ˆˆ()()(0CGAM: non-additive
continuous
tj
jtj
at
at EgXfbS )()(11
tj
jtj
at
at EgXfbS )()(22
TGAM:if E<= E*
otherwise
non-additivethreshold
Model selection criteria
1975 1980 1985 1990 1995
32.6
33.0
33.4
Eggs
year
LN(E
ggs)
1975 1980 1985 1990 1995
22.5
23.5
24.5
Age-0
year
LN(A
ge-0
)
1975 1980 1985 1990 1995
21.0
22.0
23.0
Age-1
year
LN(A
ge-1
)
1975 1980 1985 1990 1995
1819
2021
22
Age-2
year
LN(A
ge-2
)
Data: demographic Data: demographic variablesvariables
F(SB) Survey
Survey Catch-at-agemodels
Wind
year
1975 1980 1985 1990 1995
WS
3 (
m3
s-3
)
0.00
0.01
0.02
0.03
0.04
0.05
Predation
year
1975 1980 1985 1990 1995
LN
(pre
da
tion
)
24.8
25.0
25.2
25.4
25.6
25.8
26.0
26.2
Fall and Spring temperature
year
1975 1980 1985 1990 1995
tem
pe
ratu
re (
oC
)
4
6
8
10 FTST
Eggs
year
1975 1980 1985 1990 1995
LN
(eg
gs)
32.4
32.6
32.8
33.0
33.2
33.4
33.6
Data: environmental Data: environmental variablesvariables
W and TS = egg to age-0PG and TF = age-0 to age-1
age-1 to age-2
(Wind speed)3 = W Spring (TS) and Fall (TF) SST
TF
TS
Groundfish predation index (PG)
Results: model selectionResults: model selection
Egg to Age-Egg to Age-00
GAMGAM
CGAMCGAM
TGAMTGAM
X, W, TX, W, TSS
X, W, TX, W, TSS, (X*T, (X*TSS))
X, W, (X*W*TX, W, (X*W*TS S ))
0,7280,728
0,6020,602
0,6170,617
Age-0 to Age-0 to Age-1Age-1
GAMGAM
CGAMCGAM
TGAMTGAM
X, PX, PGG, T, TFF
X, PX, PGG, T, TFF, (X*T, (X*TF F ))
X, TX, TFF, (X* P, (X* PGG*T*TF F ))
0,6270,627
0,7540,754
0,3290,329
Age-1 to Age-1 to Age-2Age-2
GAMGAM
CGAMCGAM
TGAMTGAM
PPGG, T, TFF
N/AN/A
NANA
0,2790,279
Model Structure Variables CV
Results: effectsResults: effects
Egg D
ensity
Survival
Egg D
ensity
Survival
Egg D
ensity
Survival
Age-0 D
ensity
Survival
Age-0 D
ensity
Survival
Age-0 D
ensity
Survival
Survival
T S T S T S
T F T F T F
T FPG
GAM CGAM TGAM
Egg to Age0
Age-0 to Age-1
Age-1 to Age-2
Results: TGAM partitionsResults: TGAM partitions
4.0 4.5 5.0 5.5 6.0 6.5
0.0
10
.02
0.0
30
.04
Egg to Age-0
TS
W
25.0 25.2 25.4 25.6 25.8 26.0
6.5
7.0
7.5
8.0
Age-0 to Age-1
PG
TF
1975 1980 1985 1990 1995
32.5
33.0
33.5
EGGS
LN(E
ggs)
1975 1980 1985 1990 1995
2324
2526
27
AGE-0
LN(A
GE
-0)
1975 1980 1985 1990 1995
2122
2324
25
AGE-1
LN(A
GE
-1)
1975 1980 1985 1990 1995
1819
2021
2223
2425
AGE-2
LN(A
GE
-2)
Results: model simulationsResults: model simulations
DATAGAMCGAMTGAM
GAM-R2 = 0.43CGAM-R2 = 0.58TGAM-R2 = 0.65
GAM-R2 = 0.36CGAM-R2 = 0.44TGAM-R2 = 0.51 GAM-R2 = 0.59
CGAM-R2 = 0.64TGAM-R2 = 0.69
Results: model simulationsResults: model simulations
1975 1980 1985 1990 1995
32.5
33.0
33.5
EGGS
LN(E
ggs)
1975 1980 1985 1990 1995
2324
2526
27
AGE-0
LN(A
GE
-0)
1975 1980 1985 1990 1995
2122
2324
25
AGE-1
LN(A
GE
-1)
1975 1980 1985 1990 1995
1819
2021
2223
2425
AGE-2
LN(A
GE
-2)
DATAGAMCGAMTGAM
GAM-R2 = 0.43CGAM-R2 = 0.58TGAM-R2 = 0.65
GAM-R2 = 0.36CGAM-R2 = 0.44TGAM-R2 = 0.51 GAM-R2 = 0.59
CGAM-R2 = 0.64TGAM-R2 = 0.69
Results: model simulationsResults: model simulations
1975 1980 1985 1990 1995
32.5
33.0
33.5
EGGS
LN(E
ggs)
1975 1980 1985 1990 1995
2324
2526
27
AGE-0
LN(A
GE
-0)
1975 1980 1985 1990 1995
2122
2324
25
AGE-1
LN(A
GE
-1)
1975 1980 1985 1990 1995
1819
2021
2223
2425
AGE-2
LN(A
GE
-2)
DATAGAMCGAMTGAM
GAM-R2 = 0.43CGAM-R2 = 0.58TGAM-R2 = 0.65
GAM-R2 = 0.36CGAM-R2 = 0.44TGAM-R2 = 0.51 GAM-R2 = 0.59
CGAM-R2 = 0.64TGAM-R2 = 0.69
Factors affecting recruitment:Factors affecting recruitment: cross-scales (wind, temperature, community change)cross-scales (wind, temperature, community change) change across-stages (egg-age0; age0-1, age1-2)change across-stages (egg-age0; age0-1, age1-2) are non additive, i.e., interact with each other are non additive, i.e., interact with each other
(changes of DD)(changes of DD)
New Question:New Question: How do these patterns affect our ability to How do these patterns affect our ability to
forecast/manage pollock stocks in changing forecast/manage pollock stocks in changing environment?environment?
SummarySummary
Climate in North PacificClimate in North Pacific
Temperature in the GOATemperature in the GOA
Community changes in the Community changes in the GOAGOA
Mortality trends
0
1
2
3
4
5
6
1970 1975 1980 1985 1990 1995 2000
Year class
Mo
rta
lity
Juvenile mortality
Early larval mortality
Recruitment and larval mortality
18
18.5
19
19.5
20
20.5
21
21.5
0 1 2 3 4 5 6
Total larval mortality (mt)
ln(R
ec
ruit
s)
1981-88
1989-96 Immediately after the regime shift, larval mortality and recruitment were correlated
Afterwards, the relationship dissipated
There has been no trend in larval mortality
There has been a trend for increasing juvenile mortality
Control has shifted from environmental effects on larvae to predation of juveniles.
Bailey (2000) MEPS 198:215