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

Spatial variation in temperature increase

2035

2035 2100

2050*

* Based on B1 2100 Source: Lough et al. (2011)

Ocean acidification

Ganachaud et al. (2011)

Potential impacts on pearl farming•P

oorer 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

Source: Georgia Langdon

Thermocline

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

FAR

M C

EN

SU

SFarm

InspectionWater Quality Monitoring

Seeded Pearls as a % of hanging pearls and as a % of the previous years

total.

0

0

0

0

0

1

1

1

PF01

PF02

PF03

PF04

PF05

PF06

PF07

PF08

PF09

PF10

PF11

PF12

PF13

PF14

PF15

PF16

PF17

PF18

PF19

PF20

PF21

PF22

PF23

PF24

PF25

PF26

PF27

PF28

PF29

PF30

PF31

PF32

PF33

PF34

PF35

PF36

PF37

PF38

Benchm

arking

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

•Increased risks from flooding

•Stratification from higher temperatures causes de-oxygenation

Effects on tilapia

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•A

quaponics and pond aquaculture are likely to be favoured by climate change

Source: Pickering et al. (2011)