sub-decadal oceanic oscillations regulate the north-eastern atlantic shelf ecosystems
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Sub-decadal oceanic oscillations regulate the north-eastern Atlantic shelf ecosystems
Hjálmar Hátún, Payne, M., Sandø, A. and others...
Santander, 2011
Blue whiting
Sub-decadal oceanic oscillations and blue whiting recruitment
Outline
• The subpolar gyre – marine climate link and blue whiting stock dynamics
• Can we predict recruitment? – some new ideas on the sub-decadal variability.
SubtropicalGyre
SubpolarGyre
Labrador Sea convection
(Hatun et al., Science 2005)
1. The Subpolar Gyre and the marine climate
R
I
Salinity in the Irminger Current (obs.)
Salinity at Rockall (obs.)
Gyre index (GI)
Record high T and S
1. The Subpolar Gyre and the marine climate
Weak.
Strong
Simulated temperatureCold Warm
1. The Subpolar Gyre and the marine climate
Large mid-1990s changes!
Blue whiting
Blue whiting: Spawning-feeding distributions/migrations
Feeding
Spawning
Mackerel
Herring
Stor endringer i kolmule bestanden
Largest fishery in the North Atlantic!
A threefold blue whiting stock size increase
SST (in Rockall Areal)
Stock size (<- shifted 3 years)
Warm (1998-2003)Cold (1990-1996)
Spatial Shift (Blue whiting catches – all nations)
1997
Spawning distribution: (Hátún et al. 2009, CJFAS)
Post-spawning migration: (Hátún et al. 2009, PIO)
So what about blue whiting recruitment?
Need to understand the processes
(Payne et al., 2011, In Press)
North AtlanticSub-polar gyre
Recruitment
Gyre index and recruitmentnot significantly correlated
Atmosphericforcing
Wind stress curl
-5
-3
-1
1
3
5x 10
-7
-50 -40 -30 -20 -10 040
45
50
55
60
65
UK
Green-land
Anticyclonic (Curl <0)
Wind stress (ws) - arrows (NCAR/NCEP)
Curl (ws) [N/m ]
2
0
Cyclonic (Curl >0)
2. Atmosphere-gyre details
WSC = 0
SubtropicalGyre
SubpolarGyre
2. Atmosphere-gyre details
SubpolarGyre
”Inter-gyreregion”
’Window’
2. Atmosphere-gyre details
WSC = 0
SubtropicalGyre
’Navidad’
”Inter-gyreregion”
SubpolarGyre
2. Atmosphere-gyre details
Recruitment and wind stress curl
2. Recruitment
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
-30 -25 -20 -15 -10 -5 040
45
50
55
60
65
Spain
R
1980 1985 1990 1995 2000 2005 20100
1
2
3
4
5
6x 10
4
BW
Recru
itm
ent
Recruitment
Vs.
-5
-3
-1
1
3
5x 10
-7
-50 -40 -30 -20 -10 040
45
50
55
60
65
WSC
Recruitment and wind stress curl
1980 1985 1990 1995 2000 2005 2010-2
-1.5
-1
-0.5
0
0.5
1
1.5
2x 10
-7
Year
WS
C [
N/m
3]
Recruitment and wind stress curl
1980 1985 1990 1995 2000 2005 2010-2
-1.5
-1
-0.5
0
0.5
1
1.5
2x 10
-7
Year
WS
C [
N/m
3]
Nor
thw
ard
tran
spor
t
ImprovedRecruitment?
Sea surface heightand marine climate
Warmer
3. Monitoring with altimetry
Gyre Mode
Spatial pattern
(Updated from Hakkinen and Rhines, 2004)
3. Monitoring with altimetry
Time series(gyre index)
1994 1996 1998 2000 2002 2004 2006 2008 2010
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
Year
1992 1994 1996 1998 2000 2002 2004 2006 2008 2010-15
-10
-5
0
5
10
Year
dSS
H [
cm]
Transport anomalies of source waters
Western source
Eastern source
3. Monitoring with altimetry
~ 7 Sv(Pingree, 2002)
An along-Continental Slope perspective
(Data availability) Decompose onto a S-axis
Porcupine
(Hátún et al. 2009, CJFAS)
2. Hydrographic Pulses
35.1
35.15
35.2
35.25
35.3
35.35
35.4
35.45
35.5
Year
Dis
tanc
e [k
m]
1980 1985 1990 1995 2000 2005 20100
200
400
600
800
1000
1200
1400
1600
Porcupine
Shetland
Salinity @ 300m
2. Hydrographic Pulses Salinity
35.1
35.15
35.2
35.25
35.3
35.35
35.4
35.45
35.5
Year
Dis
tanc
e [k
m]
1980 1985 1990 1995 2000 2005 20100
200
400
600
800
1000
1200
1400
1600
Porcupine
Shetland
Salinity @ 300m
2. Hydrographic Pulses Salinity, currents
Wea
ker N
AC
35.1
35.15
35.2
35.25
35.3
35.35
35.4
35.45
35.5
Year
Dis
tanc
e [k
m]
1980 1985 1990 1995 2000 2005 20100
200
400
600
800
1000
1200
1400
1600
Porcupine
Shetland
Salinity @ 300m
2. Hydrographic Pulses
A new boom?
Salinity, currents and recruitment
So is the recruitment predictable?
Not with certainty -
But certainly not
if the marine climate is ignored
I ’predict’ that the 2009 year-class will be strong
1990 1995 2000 2005 2010
-6
-4
-2
0
2
4
6
8
10
12
14
Year
dS
SH
[cm
]
3. Monitoring with altimetryTransport anomalies
of source waters
1990 1995 2000 2005 2010
-6
-4
-2
0
2
4
6
8
10
12
14
Year
dS
SH
[cm
]
3. Monitoring with altimetryTransport anomalies
of source watersand blue whiting recruitment
Salt-pulses and blue whiting recruitment2. Recruitment
Porcupine
Shetland
So what about recruitment?
Bad recruitment Good recruitment
(Hátún et al., 2009, CJFAS)
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