Projected changes to aquaculture

Based on…….

Outline Freshwater aquaculture (tilapia, milkfish, freshwater prawn) Vulnerability of freshwater aquaculture Coastal aquaculture (marine shrimp, marine ornamentals) Vulnerability of coastal aquaculture

Tilapia Food security Cage culture Household subsistence production

Tilapia Livelihoods Cage culture Semi-intensive ponds Aquaponics PNG - 10-15,000 households with tilapia farms

Tilapia Tilapia farming is expanding in the region PNG 10-15,000 households Fiji produces 200-300 tonnes per year Vanuatu 65-70 tonnes p.a., hatchery established Samoa has 25 farms

Freshwater prawn Macrobrachium Hatchery-based culture (M. rosenbergii) Capture-based culture (M. lar) Fiji produces about 25 t per year

Vulnerability of freshwater aquaculture

Tilapia, freshwater prawn Likely to benefit from climate change Higher rainfall and warmer temperatures will allow farming in more places and at higher altitudes

Tilapia, freshwater prawn Increased risks from flooding Stratification from higher temperatures causes de-oxygenation

How should we respond? Build fish ponds to avoid more severe floods Photo: Avinash Singh

How should we respond? Increase aeration to combat stratification

Conclusion Freshwater pond aquaculture is likely to be favoured by climate change Source: Pickering et al. (2011)

Coastal aquaculture - livelihoods

Vulnerability of coastal aquaculture

Ocean acidification Source: IPCC (2007), Ganachaud et al. (2011)

Temperature Spatial variation in temperature increase 2035 2050* 2035 2100 * Based on B1 2100 Source: Lough et al. (2011)

Sea-level rise Projection 2035 2050 2100 IPCC 8 cm 18-38 cm 23-51 cm Semi-empirical 20-30 cm 70-110 cm 90-140 cm

Marine shrimp Expected to benefit in short term from higher temperatures In the long-term, the main threats to shrimp culture are: Sea-level rise Ocean acidification Pathogens Scarcity of fishmeal?

Marine shrimp Sea-level rise will make it difficult to: Now: crop in progress Sea-level rise will make it difficult to: dry out ponds between crops harvest shrimp Now: pond preparation Future: poor pond prep. Future: difficult to harvest

How should we adapt Modify shrimp ponds to drain well

Giant clams and marine ornamentals 2035 2050 2100 Effects due to: Increased temperature Ocean acidification Greater runoff More-intense cyclones

How should we adapt? Grow-out animals at greater depth (cooler waters) Identify sites where CO2 is reduced

Outlook for coastal aquaculture

Conclusion Scope for development over next 30-40 years Production efficiency is likely to be reduced