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Projected changes to aquaculture. Based on……. Outline. Summary of changes to surface climate and the ocean expected to affect aquaculture Projected effects on pearl farming Projected effects on tilapia and milkfish. Projected changes. Source: Lough et al. (2011), Ganachaud et al. (2011).
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Outline • Summary of changes to surface climate and the ocean expected to affect aquaculture • Projected effects on pearl farming • Projected effects on tilapia and milkfish
Projected changes Source: Lough et al. (2011), Ganachaud et al. (2011)
Temperature 2035 2050* Spatial variation in temperature increase 2035 2100 Source: Lough et al. (2011) * Based on B1 2100
Ocean acidification Ganachaud et al. (2011)
Potential impacts on pearl farming • Poorer survival of spat due to ocean acidification • Reduced pearl quality because nacre is composed of aragonite • Effects of warmer water on nacre quality • Problems due to more intense cyclones and increased stratification (e.g. deoxygenation) • BUT rise in sea level may improve flushing of lagoons Photo: Leanne Hunter
Thermocline Source: Georgia Langdon
Options for responding to present-day and future risks for pearl farming
Maintaining resilience of oysters • Mapping to identify high disease risk areas • Regulate stock within farm boundaries and carrying capacity of lagoon • Avoid overlapping farms
Environmental monitoring Farm Inspection Benchmarking Water Quality Monitoring FARM CENSUS
Anticipate and plan for losses • Expect production losses from extreme events and ‘unexpected’ causes • Ensure that financial planning for enterprises can absorb such shocks
Reduce the effects of OA and SST • Identify sites where conditions for nacre growth may be better • Progressively switch to hatchery production and selective breeding • Grow pearls at greater depth for final nacre Photo: Leanne Hunter
Effects on giant clams • Similar to pearl oysters • Grow at greater depth (cooler waters) • Identify sites where CO2 is reduced
Effects on tilapia • Likely to benefit from climate change • Higher rainfall and warmer temperatures will allow farming in more places and allow faster production
Effects on tilapia • Increased risks from flooding • Stratification from higher temperatures causes de-oxygenation
Effects on milkfish • Increased temperatures will extend the geographical range and season of fry collection • Risk from ocean acidification?
Conclusions for pearl farming • Scope for development over next 30-40 years • Production efficiency is likely to be reduced
Conclusions for freshwater fish • Aquaponics and pond aquaculture are likely to be favoured by climate change Source: Pickering et al. (2011)