Transcript 10 Vulnerability of freshwater aquaculture

Projected changes
to freshwater aquaculture
Presented by
Timothy Pickering
Authors
• 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
Key messages
• 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
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
Food security
• 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
Tilapia
Semi-intensive
culture in
earthen ponds
Aquaponics
Red Tilapia – Cage Culture
Intensive
Recirculating
Intensive flow-through
Lined ponds
Milkfish
Brackish ponds
Freshwater ponds
Cage culture
Freshwater prawn
Hatchery-based culture
Macrobrachium rosenbergii
Capture-based culture
Macrobrachium lar
Integrated taro/prawn pond culture
Monoculture
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
2035
2050*
Spatial variation
in temperature
increase
2035
* Based on B1 2100
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)
Flows in Tontouta River,
New Caledonia, after
cyclones
Source: Gehrke et al. (2011)
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
Tilapia, freshwater prawn
DFF (Fiji) Ltd Prawn Farm
• Higher rainfall should
increase the number of
sites suitable for inland
aquaculture
• But some areas may
become more prone to
flooding
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
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
How should we adapt?
• 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
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