260 likes | 524 Vues
Projected changes to aquaculture. Based on……. Outline. Freshwater aquaculture (tilapia, milkfish, f reshwater prawn) Vulnerability of freshwater aquaculture Coastal aquaculture/ mariculture (giant clams, corals, trochus , sea cucumbers) Vulnerability of coastal aquaculture. Tilapia.
E N D
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 10-15,000households with tilapia farms
Tilapia Livelihoods • Cage culture • Semi-intensive ponds • Aquaponics • PNG - 10-15,000households 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
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)
Annual value • Pearl and shrimp farming dominate • Comprise >90% of total value
Livelihoods Shrimp Pearl
Restocking Sea cucumber Giant clam Trochus Green snail
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