Projected changes to aquaculture

Based on…….

Outline Freshwater aquaculture (tilapia, milkfish, freshwater prawn) Vulnerability of freshwater aquaculture Coastal aquaculture/mariculture (giant clams, corals, trochus, sea cucumbers) Vulnerability of coastal aquaculture

Tilapia Food security Lake restocking to replace Mossambique Tilapia with Nile Tilapia PNG 10-15,000 households with tilapia farms

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

Tilapia Tilapia farming is expanding in the region Samoa has 35 farms Fiji produces 200-300 tonnes per year Solomon Islands has begun an Inland Aquaculture project to support emerging farmers A tilapia hatchery has been established in Vanuatu

Milkfish 30 – 80 t per year in Guam 5 – 15 t per year in Kiribati Four farms in Palau Capture-based culture trials in Fiji, Solomon Islands and Tonga Brackish ponds Freshwater ponds Cage culture for food, tuna-bait

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 Some areas with increased rainfall or cyclones may become more prone to flooding DFF (Fiji) Ltd freshwater prawn Farm Cyclone Mick, December 2009

Tilapia, freshwater prawn Stratification from higher temperatures causes de-oxygenation – aeration needed

Milkfish Increased temperatures will extend the geographical range and season of fry collection Risk from ocean acidification?

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

Annual value Pearl and shrimp farming dominate Comprise >90% of total value

Livelihoods Shrimp Pearl

Restocking Sea cucumber Giant clam Trochus Green snail

Vulnerability of mariculture

Marine fish, shellfish Mariculture of fish and shellfish faces major uncertainties Possible effects of acidification on larval fish and shells Applies to giant clams and cultured corals

Aquatic animal diseases Higher temperature are likely to increase prevalence of pathogens The nature and extent of future disease risks are not clear White Spot Virus WSV

Adaptations Grow ornamentals at greater depth (cooler waters) Identify sites where CO2 is reduced Selective breeding for resilience to acidification

See Chapter 11 for vulnerability of pearl oysters, shrimp, seaweed and other commodities

Conclusion Mariculture has development potential in years ahead But production efficiency is likely to be progressively affected by climate change