Content
The Pelagic Complex
Atlanto-Scandian herring
Blue whiting
NA mackerel
The most important “southern straddlers”
Other potential “southern” pelagics
Changes in distribution and migration of fish stocks
in the Northeast Atlantic Ocean due to climate
variations
Jóhann Sigurjónsson
Marine Research Institute, Reykjavik, Iceland
Capelin
The most important highly migratory species – a
“northern straddler”
Challenges of the Changing Arctic
Conference, Bergen 26-27 June 2014
Bergen conference 26-27 June 2014
Demersal stocks that are or are likely to exhibit straddling
stock behaviour/status under climatic changes
Changes in distribution and migration of fish stocks
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Ocean currents around Iceland
Ocean currents in the NE Atlantic and Arctic
Po
Ar
cti
c
lar
Atlantic
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Sea Surface Temperature (SST) north of Iceland
Warming
up in
recentsea-surface
years similar
to mid 20th
century
temperature
A new North
Icelandic
series
Bergen conference 26-27 June 2014
Sea conditions
around Iceland are
dictated by relative
strength of warm
Atlantic water, cold
Polar water and
intermediate Arctic
waters
MRI
Changes in distribution and migration of fish stocks
Straddling stocks: The Pelagic Complex
(Hanna et al. 2006)
7
Warm
Cold
Cold
Cool
Mackerel
Blue whiting
Atlanto-Scandian herring
Warm
5
o
Temperature ( C)
6
4
3
SST estimated from available
data
2
1
1869
1889
1909
1929
1949
1969
Hraun12
Hraun60
Grim12
Grim60
Rauf12
Rauf60
NIceSST
Major fish resources in the NE Atlantic – dominate the
pelagic system
Undertake northern feeding migrations during summer
Become stronger during warm water periods
Seek northward during such periods
Temperature sensitive spp
Candidates to invade the Arctic seas – not restricted to
continental shelves – but need much food !
1989 Hanna et al., 2006
Year
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
The Pelagic Straddlers
Straddling stocks: The Pelagic Complex
Capelin
80°
78°
Catches
----------------------------------Max
Current
-----------------------------------------------------------------------------------------Mackerel
1 M tons
1 M
Blue whiting
2,4M <1 M
Herring
2M 0,7 M
76°
Herring
74°
72°
Blue whiting
Mackerel
---------------------------------------------------------------
70°
68°
66°
64°
62°
60°
58°
56°
52°
48°
44°
44°
28°
12°
4°
20°
36°
Normally restricted overlap in distribution of herring and mackerel,
Based
on mackerel
H Vilhjálmsson,–J. A. Jacobsen
Utne etand
al. others
2014
but blue whiting overlaps both with herring
and
Changes in distribution and migration of fish stocks
Bergen conference 26-27 June 2014
The Pelagic Complex in relation to Crustaceans
The Pelagic Complex in relation to Crustaceans
Spawning Stock Biomass 1987-2013
14
12
Crustacean abundance index
16
1,2
Mackerel
Blue whiting
1
Herring
0,8
10
8
0,6
6
0,4
4
0,2
2
0
0
87 88 89
90 91 92 93 94
95 96 97 98 99
0 1 2 3 2005
4 5 6 7 8 92010
10 11 12 13
1990
1995
2000
Year
Intermdiate
Bergen conference 26-27 June 2014
Ár
Spawning
Stock Biomass
Hrygningarstofn
(þús. T.)
Hrygningarstofn
(þús. T.)
Spawning
Stock Biomass
16
Changes in distribution and migration of fish stocks
14
16
Makríll
14
12
Blue whiting
12
10
Herring
10
8
8
6
6
4
4
2
2
0
0
87 88 89
90 91 92 93 941995
95 96 97 98 99
0 1 2 3 42005
5 6 7 8 92010
10 11 12 13
1990
2000
Year Ár
Warm
(ICES WGWIDE 2013)
Changes in distribution and migration of fish stocks
Intermdiate
Bergen conference 26-27 June 2014
Warm
Changes in distribution and migration of fish stocks
Distribution of mackerel and herring during Nordic
pelagic survey July-August 2012
Sea Surface Temperature July 2012
Deviation from 20 yrs mean
(ICES WGWIDE 2012)
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Bergen conference 26-27 June 2014
Changes in distribution and migration
(ICES WGWIDE
of fish stocks
2012)
Átu þurrvikt (g m2)
Bergen conference 26-27 June 2014
Summer growth by age groups
120
140
700
(c) 2011
600
43-55%
160
180
gain
weight240
200 in 220
Other “southern” stocks ?
260
280
Age
Age
Age
Age
Age
Age
Age
500
400
300
200
2
3
4
5
6
7
8
More than 30 “new” species encountered last decade
Most of them not fished for commercial purposes
Most of them not “shared” stocks
Not large pelagic stocks
Exceptions:
100
Atlantic horse mackerel
Also some small clupeoid pelagics
0
120
1 May
140
160
180
200
220
Summer
Day of the year
240
260
15280
Sept
Equals approx. 2-3 million tons of food
Source: Guðm.Oskarsson et al.. 2012
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Capelin, migration and distribution
Capelin stocks
- the most important cold water or “northern”
straddler
1965-2002
After 2002
Towards the coast of Greenland
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Changes
Vilhjalmsson,
in distribution
1997
and migration
and pers
of fish
com
stocks
Bergen conference 26-27 June 2014
Iceland Capelin: Stock size
Juvenile capelin (year-class 1 and 2) in fall
Veiðistofn
Hrygningarstofn
180
Thous.tons
Stock reduced
Warm
Intermediate
Index of abundance
160
140
120
Low Recruitment
100
80
60
40
20
0
1981
1984
1987
1990
1993
1996
1999
2002
2005
2008
2011
Year
Year
Bergen conference 26-27 June 2014
(Source: MRI)
Changes in distribution and migration of fish stocks
(Source: MRI)
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Shifts in abundance of important fish stocks
Monkfish – warm water species
Impacts on Demersal Stocks
Greenland halibut – cold water species
South
S-West
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Shifts in abundance of important fish stocks
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Straddling demersal stocks ?
Monkfish – warm water species
Demersal stocks that are or could increasingly
become straddling stocks
Red fish stock
Golden redfish
Pelagic redfish
Saithe
Cod
Greenland halibut
Greenland halibut – cold water species
South
S-West
Bergen conference 26-27 June 2014
(Source: MRI)
Changes in distribution and migration of fish stocks
Major stock complexes
Greenland halibut: Stock units in the North Atlantic
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Cod distribution and spawning around
Greenland and Iceland
Additional spawning
>1927
Additional spawning
1921-27 <1917
1918-20
Main spawning
E.Hjörleifsson
Hrygning
Spawning
Grænland-Kanada
Grænland-Ísland-Færeyjar
Noregur Barentshaf
Málstofa Hafréttarstofnunar Íslands 9. nóvember 2007
Bergen conference 26-27 June 2014
Changes in distribution and migration
of fish stocks
H. Vilhjálmsson
(1997)
Cod recruitment around Iceland 1917-2011
1500
Fjöldi
No ofnýliða
recruits
Greenland migration
Grænlandsganga
Milljónir
Million fiska
fish
1000
Conclusions: Pelagic stocks
The most important “southern” straddlers in coming years are
beyond doubt the Pelagic Complex species
Although these stocks are for the time being strong and in great
abundance in Iceland and adjacent seas during the warm water
regime, it seems likely that they will somewhat decrease in size in
the near future, although it may not cool down considerably
Horsemackerel is a likely immigrant into northern waters if warm
water regime continues or becomes stronger – a new species off
Iceland and in northernmore areas
Small clupeoids may also move north
500
0
1917
1930
1940
1950
1960
1970
1980
1990
2000
2011
Árgangur
Year class
(Source: MRI)
Conclusions: Demersal stocks
Changed conditions in northern waters do not have the
same dramatic shifts in distribution and abundance of
demersal species as for the pelagics
Many smaller commercial species and stocks fluctuate
on the continental shelves within the EEZs
Greenland halibut is and will be an important straddler
to share as will be redfish stocks
Cod well known for migration between Greenland and
Iceland during warm water periods – may require
closer cooperation in the future
Cod is and will be an important straddler in the Barents
Sea and require continued cooperation
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks
Capelin, a key species in northern waters, particularly off Iceland
and in the Barents Sea, may continue at relatively low levels if the
situation continues. Will again gain strength when cooling occurs.
Continued changed distribution and migration of capelin can have
management implications and sharing of stock
Bergen conference 26-27 June 2014
Changes in distribution and migration of fish stocks