Vulnerability of coastal fisheries
- Chapter 9 Presented by
Morgan Pratchett
Importance of coastal fisheries
Fiji
Annual production (mt)
30000
25000
20000
15000
26900
10000
13851
5000
0
315
4146
Aquaculture
Freshwater
Coastal
Offshore
200000
180000
160000
140000
120000
100000
80000
60000
40000
20000
0
Subsistence
Commercial
300
All PICTs
Estimated value ($US millions)
Annual Production (mt)
Coastal Fisheries Production
Gillett 2009
250
200
150
100
50
0
Commercial and Locally-based
susbsistence
industrial tuna
coastal fisheries
fishing
Annual Production (mt)
Coastal Fisheries Production
200000
180000
160000
140000
120000
100000
80000
60000
40000
20000
0
Subsistence
Commercial
PICTS
Fiji
What are coastal (inshore) fisheries?
i.
Demersal fish
ii. Nearshore pelagics
iii. Invertebrates
What are not considered (so far)
i.
Deepwater snapper
ii. Sharks
i. Demersal fish
ii. Nearshore pelagic fish
iii. Invertebrates
Coastal fisheries - Fiji
4,180 t/yr
5,270 t/yr
17,450 t/yr
Indirect effects of climate change
60
1600
Coral cover (%)
Seagrass area
40
1200
1000
30
800
20
600
Coral cover
400
10
200
0
0
now
2035
2050
2100
Areal extent (km2)
1400
50
Effects of habitat degradation
Macroalgae
Proportional change
0.5
0
Habitat
complexity
-0.5
Coral cover
-1
0
1
2
3
4
5
6
7
8
Time after extensive coral loss (years)
9
10
Effects of habitat degradation
Macroalgae
Proportional change
0.5
0
Habitat
complexity
-0.5
Coral reef fishes
Coral cover
-1
0
1
2
3
4
5
6
7
8
Time after extensive coral loss (years)
9
10
Others
Caesionidae
Balistidae
Chanidae
Labridae
Kyphosidae
Siganidae
Mullidae
Holocentridae
Scaridae
Mugilidae
Lutjanidae
Carangidae
Acanthuridae
Serranidae
Lethrinidae
Average annual catch (kg/ year)
60000
Catch composition
50000
40000
Generalists
Not vulnerable
30000
20000
10000
Reef associated
Vulnerable
0
Coral associated
Highly vulnerable
Labridae
40
35
30
25
20
15
10
5
0
Siganidae
Holocentridae
Balistidae
Mullidae
Scaridae
Acanthuridae
Lutjanidae
Serranidae
Lethrinidae
Percentage
Catch composition - Fiji
Catch
Availability
Labridae
40
35
30
25
20
15
10
5
0
Siganidae
Holocentridae
Balistidae
Mullidae
Scaridae
Acanthuridae
Lutjanidae
Serranidae
Lethrinidae
Percentage
Catch composition - Fiji
Catch
Availability
4
3.5
3
2.5
2
1.5
1
0.5
0
8.15
8.1
pH
8.05
8
7.95
7.9
7.85
Temperature
now
2035
2050
7.8
2100
Ocean pH
Temperature change
Direct effects of climate change
Effects of temperature
100
90
80
Growth (mg/week)
70
60
Acanthochromis
polyacanthus
Maximum growth
28-30oC
50
40
30
Projected
increase
3oC by 2100
20
10
0
22
24
26
28
30
32
34
36
38
Temperature (oC)
Zarco Perello and Pratchett 2012
Effects of temperature
100
Declines in:
growth
lifespan
reproduction
90
80
Growth (mg/week)
70
60
Maximum growth
28-30oC
50
Fewer &
smaller
fishes
40
30
Projected
increase
3oC by 2100
20
10
0
22
24
26
28
30
32
34
36
38
Temperature (oC)
Zarco Perello and Pratchett 2012
Normal spawning temperature
Mortality of fertilised embryos (%)
Effects of temperature
100
90
80
70
60
50
40
30
20
10
0
27.9
29.5
32.0
32.8
33.9
Temperature (oC)
34.7
% larval survival/development
Effects of ocean acidification
Abalone
80
20 deg C
22 deg C
24 deg C
70
60
50
40
30
20
10
0
pH 8.2
pH 7.8
pH 7.6
Byrne 20120
Effects of ocean acidification
Munday et al 2012
Effects of ocean acidification
Munday et al 2012
Projected changes in
maximum fisheries production
100
80
2100
•Response conditional on emission scenario
2030
•Up
to 50% decline in production, due mostly
60
40
20
0
2000
B1
A2
decline
in demersal
fishes on fishes
to 2-5%
habitat
degradation
and effects
Potentialmay
increase
in nearshore
pelagics
•Declines
be partly
offset by slight
2-5% decline
in invertebrates
increase
in nearshore
pelagic fishes
2020
2040
2060
2080
2100
Projected coastal fisheries production
Fiji
Fisheries
Demersal fish
Nearshore
pelagic fish
Invertebrates
%
65
2035
-2 to 5%
2050
-20%
20
+15 to
+20%
20%
15
0 to 5%
-5 to
-10%
2100
Main effects
-20 to 50%
Habitat loss
and
degradation
+10%
-10 to 20%
Changes in
distribution of
tuna
Declining
aragonite
saturation
Page 54, Country summaries
Priority adaptations
1. Protect the structural complexity and
biological diversity of coral reefs, mangroves
and sea grasses to sustain fisheries and
maximize adaptation potential.
2. Recognise the ecological importance of
specific fishes (e.g, herbivorous fishes on
coral reefs), and ensure stocks of these
species are sufficient to maintain key
ecosystem functions.
Priority adaptations
3. Diversify coastal fisheries activities to target
species and habitats that will be least affected
(or favoured) by climate change
4. Build the effects of climate change into fisheries
management and planning, particularly the need
to maintain adequate spawning stocks to
overcome the shocks of greater climate extremes
Conclusions
• Coastal fisheries are critically important for
both food security and livelihoods across the
Pacific
• Effects of climate change will compound upon
existing anthropogenic disturbances and
pressures (e.g., overfishing).
Conclusions
• Improved data on coastal fisheries catches is
important for monitoring, understanding and
predicting the effects of climate change on
coastal fisheries
Reporting
– subsistence fisheries catches
– separate data for distinct fisheries sectors
and species, wherever possible
Conclusions
• Up until 2035, effects of climate change will be
difficult to detect against the backdrop of existing
anthropogenic disturbances, but urgent action on
climate change is critical to minimize long-term
impacts
% change
100
80
60
2000
B1
A2
2020
2040
2060
2080
2100