comparative studies amongst sub -arctic seas …
TRANSCRIPT
1970 1980 1990 2000
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Sca
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abun
danc
COMPARATIVE STUDIES AMONGST SUB-ARCTIC SEAS
Ken Drinkwater1 ([email protected]), George Hunt, Jr. and Franz Mueter
1Institute of Marine Research and Bjerknes Center of Climate Research, Bergen, Norway 2School of Aquatic and Fishery Sciences, University of Washington, Seattle, USA
3University of Alaska Fairbanks, School of Fisheries and Ocean Sciences, Juneau, AK, USA
ESSAS ESSAS is an IMBER regional program whose aim is to compare, quantify and predict the impact of climate variability on the productivity and sustainability of Sub-Arctic marine ecosystems.
An ESSAS comparative study between different Sub-Arctic Ecosystems is testing the hypothesis that gadoids control invertebrate abundance through predation.
N
Investigating Invertebrate-Gadoid Interactions C. Morel
West Greenland: Wieland et al. Japanese Waters: Yamamura and Sakurai
1970 1975 1980 1985 1990 1995 2000 2005 2010
Cat
ch (
'000
t)
0
50
100
150
Atlantic cod 1
offshoreinshore / coastal
Northern shrimp 2
offshoreinshore (Disko Bay)
cod
0
1000
2000
3000
4000
0
2000
4000
6000
8000
10000
1981
19
83
1985
19
87
1989
19
91
1993
19
95
1997
19
99
2001
20
03
2005
20
07
Pink
shr
imp
catc
h (t)
Cod
Ann
ual C
atch
(t)
Cod
Pink shrimp
Cod
(kg
/mile
)
Shri
mp
(tou
san
d to
nn
es)
Eastern Bering Sea: Mueter Northern Iceland: Astthorsson
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0.2
0.4
0.6
0.8
1
1.2
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1.6
1.8
2
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1
1.5
2
2.5
3
1980 1985 1990 1995 2000 2005 2010
Cod
stoc
k si
ze
Shri
mp
stoc
k si
ze
Shrimp Cod
Barents Sea: Hvingel
Ecosystem Studies of Sub-Arctic Seas (ESSAS)
NORCAN (NORway-CANada Comparison of Marine Ecosystems)
Surface Chlorophyll Concentrations from SeaWiffs
Drinkwater et al., PiO, accepted
This project has been comparing different ecosystem components between the Labrador Sea and the Norwegian/Barents seas.
ESSAS undertakes comparative studies between different Sub-Arctic Seas: •to gain scientific insights •to determine what processes are fundamental to Sub-Arctic Seas and which are unique to particular seas •to share methodologies. ESSAS has undertaken several comparative studies both within the Sub-Arctic Seas and between Sub-Arctic, Arctic and Antarctic Regions.
+ warm, salty
Change from out of phase to in phase CIs between the two regions in the late 1990s caused by shifts in atmospheric pressure systems (weakening of NAO).
Harrison et al., PiO, accepted
MENU (Comparison of Marine Ecosystems of Norway and the United States)
King crab / shrimp
2 4 6 8 10
200
300
400
500
Annual mean SST (°C)
An
nu
al p
rim
ary
prod
uct
ion
(gC
m-2
)
BS (P = 0.093)
NS (n.s.)
EBS (P = 0.039)
GOM/GB (P < 0.001)
GOA (n.s.)
0
100
200
300
400
500
600
0 10 20 30 40
Tota
l an
nu
al P
P (
gC m
-2)
Nitrate concentration of deep source water (µM)
Eastern Bering Sea (EBS)
Gulf of Alaska (GOA)
Alaska
Russia
(NOR/BAR)
Greenland
Norwegian Sea
Barents Sea
Canada
USA GB
GOM Gulf of Maine / Georges Bank (GOM/GB)
Variations in primary production depends on deep water nitrate concentrations.
Primary production increased with warming from 1998-2006 in 3 of 5 ecosystems. Drinkwater et al., PiO, 2009;
Mueter et al., PiO, 2009
Analyses indicate no consistent relationship between shrimp abundances with gadoids, nor with physical variables in the different regions. Further studies are ongoing.
CPU
E (k
g/tra
p)
ln(r
ecru
its #
milli
ons)
ln(r
ecru
its in
dex)
C
PUE
(kg/
trap)
Temperature °C
Analyses of snow crab show no relationship with gadoid abundance but do show a negative relationship with temperature for all regions investigated.
Temperature °C
Marcello et al.
Timing of the spring bloom and peak seasonal productivity are occurring progressively earlier in the year, particularly at high latitudes.
ESSAS is continuing to undertake further comparative studies using both observations and models. For more information on ESSAS and these and other comparative studies visit http://www.imr.no/essas.
Normalized Climate Indices (CIs)
- cold, fresher