Projected changes to aquaculture Solomon Islands Government Based

Projected changes to aquaculture Solomon Islands Government

Based on…….

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

Tilapia Food security • Lake restocking to replace Mossambique Tilapia with Nile Tilapia • Household subsistence production

Livelihoods Tilapia • Cage culture • Semi-intensive ponds • Aquaponics

Tilapia • Tilapia farming is expanding in the region • PNG 10 -15, 000 • Fiji produces 200 -300 tonnes per year • Samoa has 25 farms • Hatchery 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 • 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

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

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

Coastal aquaculture - livelihoods

Vulnerability of mariculture

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

Temperature 2035 2050* Spatial variation in temperature increase 2035 * Based on B 1 2100 Source: Lough et al. (2011)

Acidification and temperature • Acidification expected to affect pearl oyster larvae, juveniles and adults • Acidification and increased temperature likely to reduce pearl quality High-quality Fiji Pearls Poor lustre, defects

Temperature and increased rainfall Ice-ice Kappaphycus seaweed is vulnerable to: • temperature >30 o. C • lower salinity These conditions cause “ice-ice” and Epiphytic Filamentous Algae (EFA) outbreaks EFA

Summary 2035 • Pearls 2050 2100 Effects due to: • Seaweed • Marine ornamentals • • • Increased temperature Ocean acidification Greater runoff Sea-level rise More-intense cyclones

Key responses and adaptations

How should we respond? • Expect production losses from extreme events and ‘unexpected’ causes • Ensure that financial planning for enterprises can absorb such shocks Photos: Cathy Hair

How should we adapt? • Grow pearls at greater depth for final nacre

How should we adapt? • Long term data collection to identify sites where conditions for nacre growth may be better • Progressively switch to hatchery production and selective breeding

How should we adapt? • Select sites for seaweed farms near upwelling areas and at low risk from increased freshwater runoff • Use temperature- and salinity-tolerant strains to avoid “ice-ice” and EFA Photo: Gideon Tiroba

How should we adapt? • Grow ornamentals at greater depth (cooler waters) • Identify sites where CO 2 is reduced

Outlook for mariculture

Pearl farming • Difficult to predict effects of future production until more is known about consequences of ocean acidification

Kappaphycus seaweed • Medium-term production targets of around 1000 tonnes per year should still be achievable • But not in the same places, by the same methods, or with the same varieties

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