Projected changes to aquaculture Based on Outline Summary
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)
Temperature 2035 2050* Spatial variation in temperature increase 2035 * Based on B 1 2100 Source: Lough et al. (2011)
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 a hm nc Be ng rki Farm ction e Water Insp Qu Monito ality ring RM FA CE U NS
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 CO 2 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)
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