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Introduction to the Circumpolar World
The marine environment #2
Fisheries
Hreiðar Þór Valtýsson, MSc in Fisheries Biology
Assistant Professor, Faculty of Business and Science, University of Akureyri
Director, the Fisheries Sciences Center at the University of Akureyri
Borgir (2nd floor, office 228), Norðurslóð, 600 Akureyri
Tel.: 460 8920 (office)
E-mail: [email protected]
Office hours: By appointment
Drawings: Jón Baldur Hlíðberg – www.fauna.is
Marine species
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Hreiðar Þór Valtýsson
University of Akureyri 2016
High Arctic
• Few fish species
• Low biomass
– Fewer harvested
• Low catches
• Very few people
• Mostly subsistence
High Arctic
Low Arctic
Drawings: Jón Baldur Hlíðberg – www.fauna.is
Marine species
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Hreiðar Þór Valtýsson
University of Akureyri 2016
But the SubArctic
• Many fish species
• High biomass
• Some of the most
important commercial
fisheries in the world
High Arctic
Low Arctic
Subarctic
Arctic economies
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Hreiðar Þór Valtýsson
University of Akureyri 2016
16 greatest fishing nations (239 nations total)
Icelandic catch 1 to 2 million tonnes annually
Other 3 Arctic/subarctic
Fisheries also very important for northern Canada,
Greenland and the Faroes
Partly Arctic
fisheries
Arctic economies
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Hreiðar Þór Valtýsson
University of Akureyri 2016
Example Iceland
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Fisheries always the most important economic activity
Nearly always more than 50% of exports in goods
Export in goods from Iceland
Climate change - Global
Global warming
–
IPCC 2014
The Arctic is
warming
faster
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Hreiðar Þór Valtýsson
University of Akureyri 2016
Iceland and surrounding waters
• Situated close to the Arctic Circle in
the North Atlantic.
• Right at the boundaries of the cold
temperate and arctic zones
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Hreiðar Þór Valtýsson
University of Akureyri 2016
Iceland and surrounding waters
• Productivity of the ocean
around Iceland is high
• Biomass and biomass
production high on all
levels of the food chain
• Due to regular mixing of
sunlit surface and nutrient
rich deep water
• The mixing of the cold
currents from the north
and warm from the south
increases this mixing
• However highly variable
between years
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Hreiðar Þór Valtýsson
University of Akureyri 2016
The battle of
the currents
Drawings: Jón Baldur Hlíðberg – www.fauna.is
Marine species
Arctic
Hreiðar Þór Valtýsson 10
University of Akureyri 2016
X
X
Subarctic
X
X
Temperate
X
X
Iceland and surrounding waters
Hreiðar Þór Valtýsson 11
University of Akureyri 2016
Arctic species
Greenland halibut
• North pacific and North Atlantic
• The second largest predatory fish in
high Arctic waters
• Very valuable
• No fisheries agreements
• Declining stock size
• Warming or overfishing ???
Hreiðar Þór Valtýsson 12
University of Akureyri 2016
Arctic species
Northern (or pink) shrimp
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•
•
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North pacific and North Atlantic
Very important in the N. Atlantic
Shrimp fisheries mainly north of
Iceland => cold water species
For a time the second most
important commercial species in
Iceland
Then a disaster ........
Hreiðar Þór Valtýsson 13
University of Akureyri 2016
Arctic species
Hreiðar Þór Valtýsson 14
University of Akureyri 2016
Northern shrimp and cod
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•
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The stock collapsed and the catch collapsed
Reason, warming trend in waters north of Iceland
However not directly the temperature
=> more cod in the area north of Iceland (the shrimp can
actually well tolerate this temperature) but ...
=> the cod eats shrimp
What about
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Greenland ?
Newfoundland ?
Arctic species
Scallop
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N Atlantic, closely related in N Pacific
Chlamys islandica – the Icelandic scallop
Important fisheries in western Iceland
Unexpected collapse of the fishery
Now no fishery ....... Why?
The climate became warmer but the scallop
is supposed to tolerate warmer waters !
• Studies revealed a protists disease that
killed them
• In normal (cold) conditions it is to cold for
the protists
• It came with the warmer waters and wiped
out the scallop stock
Hreiðar Þór Valtýsson 15
University of Akureyri 2016
Arctic species
Capelin
• North Pacific and North Atlantic
• A small cold water species and very
abundant north of Iceland.
• However spawns in shallow and
warmer waters off the south coast.
• It is during these migrations that it
becomes the most important food for
many other marine species in
Icelandic waters
• Usually spawns at the age of 3 and
then dies.
Hreiðar Þór Valtýsson 16
University of Akureyri 2016
Arctic species
Hreiðar Þór Valtýsson 17
University of Akureyri 2016
Capelin
• Annual caches more than 1.000.000 t, almost as high as all other species
combined
• Even if it is a cold water species the effects of warming climate are
uncertain as it depends on warm waters for spawning
• In previous warm periods it has simply shifted from spawning and spawned
in the waters north of Iceland.
• We do not know if the stock was smaller
Arctic species
Capelin
• The distribution has been
changing
• In previous warm periods
it has simply shifted from
spawning and spawned in
the waters north of
Iceland.
• We do not know if the
stock was smaller
Hreiðar Þór Valtýsson 18
University of Akureyri 2016
Sub Arctic species
Hreiðar Þór Valtýsson 19
University of Akureyri 2016
Herring
• One of the most abundant fish in the world when the stock is in
good conditions, probably the largest in the N. Atlantic
• Fisheries very important for many nations through centuries.
• Usually the 2nd most important fish in Iceland, after cod
• Most stocks did collapse due to heavy fisheries between 1965
and 1975
• Have recovered
2.500.000
2.000.000
Other nations
Catch (t)
Icelandic catch
1.500.000
1.000.000
500.000
0
1951 1956 1961 1966 1971 1976 1981 1986 1991 1996 2001
Sub Arctic species
Herring
• Cooling climate also
to blame?
Hreiðar Þór Valtýsson 20
University of Akureyri 2016
Sub Arctic species
Herring
• The herring stock will probably increase
in size in northern waters if the warming
climate will continue
• Given that the fishery is restricted
• And diseases will end
Hreiðar Þór Valtýsson 21
University of Akureyri 2016
Sub Arctic species
Cod
• North Atlantic, closely related
species in North Pacific
• Economically the most important
species during most of the centuries,
a valuable species per kg
• Since the stock is quite large and he
fish is greedy it also has a great
ecological impact
• Historically the largest stocks off
Newfoundland (now collapsed),
Barents Sea and Iceland
• All around Iceland
Hreiðar Þór Valtýsson 22
University of Akureyri 2016
Sub Arctic species
Cod
• Main spawning grounds
(meginhrygningarstöðvar) are off the
south coast
• Egg and larvae drift west and then
north, occasionally also to Greenland
• Main juvenile grounds
(meginuppeldisstöðvar) are off the
north coast
• Main feeding areas after they are
mature are where the cold and warm
currents meet off the west and east
coast
Hreiðar Þór Valtýsson 23
University of Akureyri 2016
Sub Arctic species
Hreiðar Þór Valtýsson 24
University of Akureyri 2016
Cod
• Very small native cod stock in Greenland
• During warm periods cod can however become very abundant
• new grounds open up
• Due to larval drift from Icelandic grounds
• Is self sustained during warm periods but collapses in cold
• A large part of this stock migrates back to Iceland to spawn and stays there
• Very good for the Icelandic
cod fisheries
• Mainly because of that it
has been predicted that
the cod stock in Icelandic
waters will grow with
warming climate
• Has not happened (yet?)
Sub Arctic species
Hreiðar Þór Valtýsson 25
University of Akureyri 2016
Capelin and cod
• However ……..
• The subarctic cod depends heavily on the arctic capelin as food
• If the capelin stock will be reduced due to warming it will have adverse
effects on the cod stock
• This causes great uncertainties on the fate of the cod stock because
warmer waters might either mean larger cod stock as cod in warmer waters
generally grows faster (such as in the
North sea) or it might mean smaller
cod stock if the capelin stock collapses
Sub Arctic species
Northern shrimp and cod
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This relationship between
shrimp and cod now well
known in many other areas
These species just don't
mix, you cannot have both
in abundance
Warming climate will (given
that the cod stocks are not
heavily overfished) drive
shrimp stocks down or
further north
Hreiðar Þór Valtýsson 26
University of Akureyri 2016
Temperate species
Hreiðar Þór Valtýsson 27
University of Akureyri 2016
Even more southern species
Temperate species moving further north
Blue- fin tuna
Mackerel
Norway lobster
Monkfish or anglerfish
Iceland and surrounding waters
Hreiðar Þór Valtýsson 28
University of Akureyri 2016
Summary if warming continues in Icelandic waters
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Valuable species added to the Icelandic fisheries (temperate)
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Blue fin tuna
Mackerel
Valuable species will increase in abundance (subarctic and temperate)
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Herring
Haddock
Monkfish
Lobster
(not in Greenlandic waters but might if warmer)
(not in Greenlandic waters but might if warmer)
Valuable species will decline in numbers (Arctic)
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Shrimp
Scallop
Valuable species that are great uncertainties about (arctic an subarctic)
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Cod
Greenland halibut
(probably increase)
(probably decline)
Iceland and surrounding waters
Hreiðar Þór Valtýsson 29
University of Akureyri 2016
Norwegian and
Barents Seas
The same species and
the same consequences
Global warming and fisheries
Hreiðar Þór Valtýsson 30
University of Akureyri 2016
What happens with warming oceans in the north
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A very few animals just do not tolerate higher temperatures
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More diseases
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cold water species losers
Warmer water species winners
More/different predators
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Especially cold waters species not tolerant
Warmer water species more tolerant
More/different competitors for food
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Usually in the tropics
cold water species losers
Warmer water species winners
Different food sources
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Animals might not be able to change diet
Global warming and fisheries
Humans and fisheries
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Humans are however very adaptive
Collapse of the cod in Newfoundland led to
an great increase in the shrimp and crab
fisheries (previously eaten by cod)
Fishery for those is now actually more
valuable than the cod fishery before
Warming trend in Greenland also meant that
seal numbers decreased and cod numbers
increased
Former sealers therefore became cod fishers
and profited well
A shift in the other direction is however
more difficult
Hreiðar Þór Valtýsson 31
University of Akureyri 2016
Global warming and fisheries
Hreiðar Þór Valtýsson 32
University of Akureyri 2016
Summary of threats to Arctic species due to warming
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Arctic animals will decline, especially marine mammals
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More competition with species from warmer waters
Loss of suitable habitat, increased risk of diseases, more pollution, more human traffic
The species are however few of little commercial interest
Subarctic species might however increase in numbers or simply move
further north as their normal distributional range gets to warm
–
Many of these are fishes of great commercial interest
Conclusion
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If the Arctic will continue to warm it will probably still be teaming with life,
there might even be more life
This will however be very different from the current as warmer water
species will move in and pure Arctic species will retreat north
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It is however impossible to retreat further north when you are on the North Pole
Commercial fisheries will benefit
Management problems as fish will move between countries
Global warming and fisheries
Hreiðar Þór Valtýsson 33
University of Akureyri 2016
The rest of the globe?
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More of the worlds waters will get warm
BUT warm waters are LESS productive than cold
Less catch in warm climates
Often poor and undeveloped countries
Many people
=> Big problem
Global warming and fisheries
Hreiðar Þór Valtýsson 34
University of Akureyri 2016
How about the globe?
Cold countries
Warm countries
Cheung, W. W., Lam, V. W. Y.,
Sarmiento, J. L., Kearney, K.,
Watson, R. E. G., Zeller, D., & Pauly,
D. (2009). Large-scale redistribution
of maximum fisheries catch
potential in the global ocean under
climate change. Global Change
Biology, 16(1), 24–35.