Projected changes to freshwater aquaculture
Presented byTimothy Pickering
• This presentation is based on Chapter 11 ‘Vulnerability of aquaculture in the tropical Pacific to climate change’ in the book Vulnerability of Tropical Pacific Fisheries and Aquaculture to Climate Change, edited by JD Bell, JE Johnson and AJ Hobday and published by SPC in 2011.
• The authors of Chapter 11 are: Timothy Pickering, Ben Ponia, Cathy Hair, Paul Southgate, Elvira Poloczanska, Luc Della Patrona, Antoine Teitelbaum, Chadag Mohan, Michael Phillips, Johann Bell and Sena De Silva
Authors
• Freshwater aquaculture in the Pacific should benefit from climate change
• Plans to increase future production and livelihoods from freshwater aquaculture will stay on track
• Freshwater aquaculture is an adaptation to effects of climate change on coastal fisheries
Key messages
Current and projected freshwater aquaculture production
Food security• Culture of cheap
freshwater fish for food security is gaining a higher priority
• ‘Drivers’ are increasing populations and a decline in the coastal fisheries
• Pond aquaculture is one of 3 major strategies, along with: low-cost inshore FADs increased landings of
• Small-pond aquaculture will be least in quantity
• But products have high quality (freshness, nutrition) and availability
Food security
Recirculating
Red Tilapia – Cage Culture
Aquaponics
IntensiveIntensive flow-through
Semi-intensive culture in earthen
ponds
Tilapia
Lined ponds
Brackish pondsMilkfishFreshwater ponds
Cage culture
Integrated taro/prawn pond culture Monoculture
Macrobrachium rosenbergii
Hatchery-based cultureHatchery-based culture
Capture-based cultureCapture-based culture
Macrobrachium lar
Freshwater prawn
SME approaches to food security
• Household-level aquaculture for subsistence is only viable with on-going government support
• Challenge is to add a layer of viable SME-scale commercial-market aquaculture for peri-urban markets
Existing tilapia production
• Difficult to estimate
• Many small-scale farmers in remote places with repeated (unmeasured) small harvests
Tilapia production• Tilapia aquaculture continues to expand in the region
• Fiji harvests faround 100 – 300 tonnes
• PNG reports 100 tonnes per year to FAO, but number of farms is 10,000 – 20,000
• Samoa now has 25 farms
• Solomon Islands has an Inland Aquaculture project to support emerging farmers
• Hatchery established in Vanuatu
Livelihoods
Tilapia
Tilapia
Milkfish Production• 30 – 80 tonnes per year in
intensive systems in Guam
• 5 – 15 tonnes per year in Kiribati
• Four farms now operate in Palau
• Capture-based culture trials underway in Fiji, Solomon Islands and Tonga
Freshwater prawn production
• Fiji: 25 tonnes per year
• Vanuatu has established a hatchery
• Other PICTs are interested (PNG, Cook Islands).
• PICTs could produce several hundred tonnes per year
Vulnerability of freshwater aquaculture
Projected climates changes
Source: Lough et al. (2011), Ganachaud et al. (2011)
Temperature
Spatial variation in temperature increase
2035
2035 2100
2050*
* Based on B1 2100 Source: Lough et al. (2011)
Rainfall
Spatial variation in rainfall (winter)
2035 2100
Source: Lough et al. (2011)
Greater climatic variation• Extremes will become more extreme • Expect the unexpected! (droughts, too)
Source: Gehrke et al. (2011)
Flows in Tontouta River, New Caledonia, after cyclones
Tilapia, freshwater prawn
• Tilapia aquaculture has a low vulnerability and may benefit from climate change
• Temperatures suitable for tilapia and prawn farming will extended higher latitudes and altitudes
• Higher rainfall should increase the number of sites suitable for inland aquaculture
• But some areas may become more prone to flooding
DFF (Fiji) Ltd Prawn Farm
Cyclone Mick, December 2009
Tilapia, freshwater prawn
• Increased risk of stratification from higher temperatures causing de-oxygenation; pond aeration may be needed
• Greater heat stress, and incidence of pathogens
Tilapia, freshwater prawn
Milkfish
• Increased temperatures will extend the geographical range of spawners and season for fry collection
• Supply of fry may be at risk from effects of ocean acidification on larval behaviour
Summary of vulnerability
Key adaptations
How should we adapt?
• Build fish ponds to avoid more severe floods
Photo: Avinash Singh
How should we adapt?• Prepare to increase flushing and aeration of
ponds to combat stratification
Photo: Jacques Patrois
• Develop freshwater aquaculture for food security and livelihoods
• Limit farming of tilapia to catchments where tilapia are already established in the wild or where there is a chronic shortage of fish
How should we adapt?
Conclusions• Freshwater pond aquaculture is likely to be
favoured by climate change
Conclusions
• Aspirations for significant future production and livelihoods from inland aquaculture can be realised
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