Vulnerability of coastal fisheries - Chapter 9 -
Presented byMorgan Pratchett
Importance of coastal fisheriesFiji
Coastal Fisheries Production
Gillett 2009
Coastal Fisheries Production
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
17,450 t/yr
5,270 t/yr
4,180 t/yr
Indirect effects of climate change
Seagrass area
Coral cover
65% decline in abundance
and diversity of fishes
Pro
port
iona
l cha
nge
Time after extensive coral loss (years)
0 1 2 3 4 5 6 7 8 9 10
0.5
0
-0.5
-1
Macroalgae
Coral cover
Habitatcomplexity
Effects of habitat degradation
Pro
port
iona
l cha
nge
Time after extensive coral loss (years)
0 1 2 3 4 5 6 7 8 9 10
0.5
0
-0.5
-1
Coral reef fishes
Macroalgae
Coral cover
Habitatcomplexity
Effects of habitat degradation
Coral associatedHighly vulnerable
Reef associatedVulnerable
GeneralistsNot vulnerable
Catch composition
Catch composition - Fiji
Catch composition - Fiji
Direct effects of climate change
Temperature
pH
Temperature (oC)Temperature (oC)
Maximum growth28-30oC
Acanthochromis polyacanthus
Projected Projected increaseincrease
33ooC by 2100C by 2100
Effects of temperature
Zarco Perello and Pratchett 2012
Maximum growth28-30oC
Effects of temperature
Fewer &smaller fishes
Declines in: growth lifespan reproduction
Projected Projected increaseincrease
33ooC by 2100C by 2100
Temperature (oC)Temperature (oC)
Zarco Perello and Pratchett 2012
Effects of temperature
Nor
mal
spa
wni
ng t
empe
ratu
re
Effects of ocean acidificationAbalone
Byrne 20120
Effects of ocean acidification
Munday et al 2012
Effects of ocean acidification
Munday et al 2012
Pro
ject
ed c
hang
es in
m
axim
um f
ishe
ries
prod
uctio
n
2000 2020 2040 2060 2080 2100
100
80
60
40
20
0
B1A2
20302-5% decline in demersal fishesPotential increase in nearshore pelagics2-5% decline in invertebrates
2100•Response conditional on emission scenario•Up to 50% decline in production, due mostly to habitat degradation and effects on fishes•Declines may be partly offset by slight increase in nearshore pelagic fishes
Projected coastal fisheries productionFiji
Fisheries % 2035 2050 2100 Main effects
Demersal fish 65 -2 to -5% -20% -20 to -
50%
Habitat loss and
degradation
Nearshore pelagic fish 20 +15 to
20% +20% +10%Changes in
distribution of tuna
Invertebrates 15 0 to -5%
-5 to -10%
-10 to -20%
Declining aragonite saturation
Page 54, Country summaries
Priority adaptations1. 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 adaptations3. 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 fisheriesReporting– subsistence fisheries catches– separate data for distinct fisheries sectors
and species, wherever possible
• 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
Conclusions%
cha
nge
2000 2020 2040 2060 2080 2100
100
80
60
B1A2