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