Projected changes to coastal fisheries Solomon Islands Government
Jan 04, 2016
Projected changes to coastal fisheries
Solomon Islands Government
Based on......
Outline
• Main components of coastal fisheries• Indirect effects of climate change• Direct effects of climate change• Projected changes to coastal fisheries
production• Priority management measures
Coastal fisheries – Solomon Islands
What are coastal fisheries?
• Demersal fish• Nearshore pelagics • Invertebrates
Species not considered • Deepwater snapper• Sharks
Demersal fish
Nearshore pelagic fish
Invertebrates
Coastal fisheries – Solomon Islands
8,925 t/yr
5,750 t/yr
3,575 t/yr
Gillett 2009
Indirect effects of climate change
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 – Solomon IslandsPe
rcen
t
Catch
Availability
Importance of herbivorous fish
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 2012
Effects of ocean acidification
Munday et al 2012
Projected coastal fisheries productionSolomon Islands
Fisheries % catch 2035 2050 2100 Main effects
Demersal fish 50 -2 to -5% -20% -20 to
-50%
Habitat loss and
degradation
Nearshore pelagic fish 31 0% -10% -15 to
-20%
Changes in distribution of
tuna
Invertebrates 19 0 to -5%
-5 to -10%
-10 to -20%
Ocean acidification
Priority management measures1. Protect structural complexity and biological
diversity of coral reefs, mangroves and seagrass to sustain fisheries and maximise adaptation potential
2. Recognise ecological importance of herbivorous fish and ensure stocks are sufficient to maintain ecosystem functions
3. Maintain adequate spawning stocks of all species to help overcome the shocks of greater climate extremes
Conclusions• Coastal fisheries are critically important for both
food security and livelihoods• Effects of climate change will add to existing
pressures (e.g. overfishing)• Improved catch data are needed for monitoring
effects of climate change on coastal fisheries: separate data for each main category of
coastal fisheries subsistence fisheries catches
Thank you