spatial distribution of fish stocks in a climate perspective nordic climate fish conference 2011,...
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Spatial distribution of fish stocks in a climate perspective
Nordic Climate Fish Conference 2011, Solstrand
Geir Odd Johansen
Overview
• FishExChange objectives• The FishExChange database• Data examples• Looking for important factors influencing the
variation in geographical distribution• Ambient temperature• The complex interplay• Conclusions
FEC principal objective
• Evaluate the effect of climate change in the Barents Sea and adjacent areas on distribution of fish stocks, in perspective of national marine areas
• Further, evaluate what effect this will have on division of national fish quotas and economical consequences for the fisheries
Spatial approach
FEC objectives
FEC Task 2
• The fish stocks– Based on deliverables from Task 1
(oceanography)– Age specific spatial fields (maps) of historical fish
distributions• Mechanisms behind spatial distribution
– Links to climate indicators– Interactions between species– Cover most of the life history
– Spatial fields (maps) of most likely future fish distribution
FEC objectives
ChallengeData heterogeneity in space and time
The FEC database
Allowing data to meet in a common
framework andmaking them talk
together!
Climate data
Model output
Fish survey data
Fisheries data
Horizontal, vertical, and temporal structure on different scales
Data from fish surveys in the FEC database
The FEC database
Data from fish surveys in the FEC database
• Commercial species• Based on different sources of raw data• Synoptic surveys for abundance estimation• Trawl catches corrected for swept area• Comprehensive metadata• Protocols for planning, preparation of data
and input• Data catalogues with temporal coverage
The FEC database
Data from fish surveys in the FEC database
• 0-group autumn, pelagic trawl– Blue whiting, capelin, cod, Greenland halibut,
haddock, herring, mackerel, redfish, saithe and polar cod
• Cod, bottom trawl– Winter survey, 5 cm size groups, age 1-13+– Summer/autumn/ecosystem surveys 5 cm size gr.
• Haddock, bottom trawl– Winter survey, 5 cm size groups, age soon– Summer/autumn/ecosystem surveys 5 cm size gr.
The FEC database
Data from fish surveys in the FEC database
• Capelin, acoustic surveys autumn– Age 1-5
• Polar cod , acoustic surveys autumn– Age 1-5
• Saithe, acoustic survey autumn planned– Winter survey, 5 cm size groups, age soon– Summer/autumn/ecosystem surveys 5 cm size gr.
• + T, salinity and catch data
The FEC database
Other interesting species
• Blue whiting (Micromesistius poutassou Risso, 1827)
• Entering the BS from south-west
• High abundance in 2001-2007
• Interact with other species
The FEC database
Distribution area Spawning area
Other interesting species
• Atlantic mackerel (Scomber scombrus L.)– Observed at least as north as 74°N– Recently caught off the Murman coast
• Several fish species related to benthic habitats (e.g. eelpouts (Zoarcidae) and sculpins (Cottidae)– Habitat specific– Sensitive to temperature variation
The FEC database
What about the data?
Data example
• Example: Winter bottom trawl survey in the Barents Sea
• 1981-2009• Cod ≥ 45 cm (~ catchable size)• Density (No. Fish / nmi2)
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1981
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1982
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1983
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1984
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1985
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1986
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1987
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1988
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1989
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1990
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1991
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1992
Expansion of survey area from 1993 and onwards!
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1993
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1994
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1995
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1996
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1997 Limited survey coverage
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1998 Limited survey coverage
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1999 Limited survey coverage
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2000
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2001
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2002
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2003
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2004
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2005
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2006
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2007
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2008
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
2009
Distribution of NEA cod
Variation in geographical distribution
50° E30° E
50° E30° E10° E
75°
N70
° N
75°
N70
° N
1994
1980 1985 1990 1995 2000 2005 2010
71.5
72.0
72.5
73.0
Year
Ce
ntr
e o
f gra
vity
, co
d >
45
cm
, °N
74
75
76
77
78
Ice
co
ver
- so
uth
ern
lim
it, °
N
Distribution of NEA cod
In the Barents Sea, cod appeared in large quantities on Bear Island Bank in response to the warming of the early 20th century, resulting in the reestablishment of a cod fishery there after an absence of almost 40 years (Blacker, 1957). Cod also penetrated farther east to Novaya Zemlya and north of West Svalbard, during the 1920s (Beverton and Lee, 1965). Similar effects at west Greenland and Iceland.
Drinkwater 2005
Variation in geographical distribution
Spawning sites of NEA cod
Variation in geographical distribution
Cold periods:- Southwards displacement- Decreasing spawning biomass
Hot periods - Northwards displacement- Increasing spawning biomass
Sundby and Nakken (2008) IJMS
NEA cod the first year of life
Variation in geographical distribution
1980 1985 1990 1995 2000 2005 2010
1100
000
1400
000
Survey area
spatdat$Year
spat
dat$
AO
S
1980 1985 1990 1995 2000 2005 2010
4e+
058e
+05
Area of occupancy
spatdat$Year
spat
dat$
AO
O
1980 1985 1990 1995 2000 2005 2010
2530
3540
Easterly centre of gravity
spatdat$Year
spat
dat$
Cen
terX
1980 1985 1990 1995 2000 2005 2010
3032
3436
Northerly centre of gravity
spatdat$Year
spat
dat$
Cen
terY
NEA cod 1 yr old, winter
Variation in geographical distribution
1980 1985 1990 1995 2000 2005 2010
4e+
056e
+05
8e+
05Survey area
spatdat$Year
spat
dat$
AO
S
1980 1985 1990 1995 2000 2005 2010
2e+
056e
+05
Area of occupancy
spatdat$Year
spat
dat$
AO
O
1980 1985 1990 1995 2000 2005 2010
3236
4044
Easterly centre of gravity
spatdat$Year
spat
dat$
Cen
terX
1980 1985 1990 1995 2000 2005 2010
2428
32
Northerly centre of gravity
spatdat$Year
spat
dat$
Cen
terY
NEA cod 4 yr old, winter
Variation in geographical distribution
1980 1985 1990 1995 2000 2005 2010
4e+
056e
+05
8e+
05Survey area
spatdat$Year
spat
dat$
AO
S
1980 1985 1990 1995 2000 2005 2010
3e+
055e
+05
7e+
05
Area of occupancy
spatdat$Year
spat
dat$
AO
O
1980 1985 1990 1995 2000 2005 2010
3032
3436
38
Easterly centre of gravity
spatdat$Year
spat
dat$
Cen
terX
1980 1985 1990 1995 2000 2005 2010
2628
3032
Northerly centre of gravity
spatdat$Year
spat
dat$
Cen
terY
NEA cod 8 yr old, winter
Variation in geographical distribution
1980 1985 1990 1995 2000 2005 2010
4e+
056e
+05
8e+
05
Survey area
spatdat$Year
spat
dat$
AO
S
1980 1985 1990 1995 2000 2005 2010
1e+
053e
+05
Area of occupancy
spatdat$Year
spat
dat$
AO
O
1980 1985 1990 1995 2000 2005 2010
2630
34
Easterly centre of gravity
spatdat$Year
spat
dat$
Cen
terX
1980 1985 1990 1995 2000 2005 2010
2527
29
Northerly centre of gravity
spatdat$Year
spat
dat$
Cen
terY
Stock abundance
Variation in geographical distribution
Ambient temperature
Ambient temperature
Based on bottom temperatures in winter
1 yr old, winter
4 yr old, winter
8 yr old, winter
1980 1985 1990 1995 2000 2005
12
34
5
Ambient temperature for cod
ambient_temp$year
ambi
ent_
tem
p$co
dT1
Factors influencing geographical distribution
The complex interplay
Planque et al. 2010
spatial distribution
geographical attachment
environmental conditions
density dependent
habitat selection
spatial dependency
demographic structure
Persistence
species interactions
Conclusions
Conclusions
• Cod does not show signs of moving out of Norwegian exclusive economic zone - - - yet
• The period 1980-2010 is short in a global climate perspective• Study effects of climate variation
• Abundance is important for area of occupancy of a fish stock
• Important fish stocks for at least 1000 years• “Always” present even if climate varies?
Future challenges
“Prediction is very difficult, especially of the future” Niels Bohr, Danish physicist (1885 - 1962)
Temperature in the Kola hydrographic section
2,5
3,0
3,5
4,0
4,5
5,0
5,5
6,0
1900 1920 1940 1960 1980 2000 2020 2040 2060 2080
Temperatur
År ?
Year-to-year variation Long-time trend Long-term prognosis
”unknown situation”
”known situation”