Day 3 06 Coastal Fisheries M. Pratchett
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Transcript Day 3 06 Coastal Fisheries M. Pratchett
7th SPC HOF meeting
Effects of climate change on coastal fisheries
Morgan Pratchett, Philip Munday, Nicholas Graham, Mecki Kronen*, Silvia
Pinca*, Kim Friedman*, Tom Brewer, Johann Bell*, Shaun Wilson, Joshua
Cinner, Jeff Kinch, Rebecca Lawton, Ashley Williams*, Lindsay Chapman*,
and Franck Magron*
Climate change and coastal fisheries
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Four categories of coastal fisheries
1. Demersal finfishes
2. Nearshore pelagics
3. Targeted invertebrates
Shallow sub tidal and
Climate change and coastal4.
fisheries
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intertidal invertebrates
Climate change and coastal fisheries
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Others
Balistidae
Labridae
Mullidae
Kyphosidae
Holocentridae
Siganidae
Mugilidae
Carangidae
Lutjanidae
Serranidae
Scaridae
Acanthuridae
Lethrinidae
Proportional use species
Main types of species considered
Demersal finfishes
0.15
0.1
0.05
0
Major changes in environmental conditions
1. Sea surface temperature (SST)
Temperature increase (oC)
4
High emissions
A2
3
2
B1
Low emissions
1
0
1980
2000Climate 2020
2040 fisheries
2060
change and coastal
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2080
2100
Redistribution of species with increased temperature
Increasing latitude
Decreasing temperature
Climate change and coastal fisheries
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Redistribution of potential fisheries catch
By 2050, potential fisheries catches will decline by ~40% in the
tropical Pacific if species are free to move poleward with
increasing temperatures (Cheung et al. 2010)
Climate change and coastal fisheries
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Climate change and coastal fisheries
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Climate change and coastal fisheries
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Major changes in environmental conditions
1. Sea surface temperature (SST)
High emissions
Temperature increase (oC)
4
A2
3
2
B1
1
0
1980
Typical bleaching
threshold
2000
2020
2040
2060
2080
Climate change and coastal fisheries
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Low emissions
2100
Major changes in environmental conditions
2. Coral cover
0
-10
Severity of declines
-20
-30
-40
-50
Low emissions
-60
B1
-70
-80
-90
High emissions
-100
1980
2000
2020
2040
2060
Climate change and coastal fisheries
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2080
A2
2100
Major changes in environmental conditions
2. Coral cover
0
-10
Severity of declines
-20
-30
Effective local
management
-40
by teams of experts
-50
-60
B1
-70
-80
-90
-100
1980
A2
2000
2020
2040
2060
Climate change and coastal fisheries
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2080
2100
Declines in other habitats are also
expected to affect coastal fisheries
Habitat
2035
B1/A2
2100
B1
A2
Mangroves
-10 to > -10% -50 to -70% -60 to -80%
Seagrass
< -5 to -20%
-5 to -35%
-10 to -50%
Linkages between coral reefs, mangroves and seagrasses in
the life cycles of coastal fish and invertebrates
Climate change and coastal fisheries
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Climate change and coastal fisheries
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Fish declines exacerbated by
structural collapse of coral habitats
65% decline in abundance
and diversity of fishes
Climate change and coastal fisheries
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Major changes in environmental conditions
3. Aragonite saturation (ocean acidification)
5
Severity of declines
4.5
4
3.5
3
2.5
2
1980
2000
2020
2040
2060
Climate change and coastal fisheries
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2080
2100
Major changes in environmental conditions
3. Aragonite saturation (ocean acidification)
Loss of skeleton for corals growing under acidified conditions (Fine and Tchernov 2007)
Climate change and coastal fisheries
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Major changes in environmental conditions
3. Aragonite saturation (ocean acidification)
Climate change and coastal fisheries
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7th SPC HOF meeting
Effects of climate change on coastal fisheries
Demersal
finfish
Nearshore pelagic fish
Targeted
invertebrates
Shallow
Sub-tidal &
intertidal
invertebrates
WARM &
ARCH
PEQD, NPTG
& SPSG
-5%
0%
+40%
-5%
0%
2100 B1
-20%
-10%
+35%
-10%
-5%
2100 A2
-50%
-15%
+30%
-20%
-10%
2035 B1/A2
Low
Confidence
Medium
High
Climate change and coastal fisheries
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Very High
7th SPC HOF meeting
Effects of climate change on coastal fisheries
Coastal fisheries are sensitive to changes in
- habitat quality and quantity
- sea surface temperature
- seawater chemistry (pH)
- ocean currents and nutrient availability
Up until 2035 effects of climate change may be
difficult to distinguish from sustained exploitation and
habitat degradation
Effective local management will greatly reduce
longer-term impacts of climate change on coastal
fisheries
Climate change and coastal fisheries
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7th SPC HOF meeting
Adaptation and management recommendations
Reverse or reduce local anthropogenic impacts
that reduce the structural complexity and
biological diversity of critical coastal habitats.
Keep production of demersal finfish and
invertebrates within sustainable limits; rebuilding
populations of over-exploited species
Diversify fishing activities (and livelihoods) to
reduce reliance on fisheries species that are
highly vulnerable to climate change
Climate change and coastal fisheries
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