Projected changes to aquaculture
Jan 13, 2016
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
• Lake restocking to replace Mossambique Tilapia with Nile Tilapia
• PNG 10-15,000 households with tilapia farms
TilapiaFood security
• Cage culture
• Semi-intensive ponds
• Aquaponics
• PNG - 10-15,000 households with tilapia farms
TilapiaLivelihoods
Tilapia•T
ilapia 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
Freshwater ponds Cage culture for food, tuna-bait
Brackish ponds
• 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
• Hatchery-based culture Hatchery-based culture ((M. rosenbergii)
• Capture-based culture Capture-based culture ((M. lar)
Freshwater prawn Macrobrachium
• 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.
•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
Tilapia, freshwater prawn
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•F
reshwater 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
Sea cucumber
Giant clam Trochus Green snail
Restocking
Vulnerability of mariculture
Marine fish, shellfish•M
ariculture 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