1. Rice vs fish
(only 35% produce surplus)
Photo:cc: SabaiPhoto:cc: Nestle
Sanjiv de Silva
Moto Adventures
March 19, 2013
IWMI-ACIAR workshop
Phnom Penh
Water for a food-secure world
www.iwmi.org

2. Objective & Discussion Questions
Objective
Review the importance and urgency of risks to small-scale fisheries
posed by irrigation intensification, and potential options to mitigate
them.
Discussion Questions
• How can we move this discussion forward?
• What research gaps exist to move forward?
• Who should be involved? How do we involve them?
Water for a food-secure world
www.iwmi.org

3. Rice-field fisheries
• Fishing and foraging in flooded rice fields is important for
food and seasonal income for rural households
– rice-fields provide 50 – 250 kg of fish and OAA / family / year
– economic value can equal or exceed that of rice
– important component of nutrition particularly for the poor
– common pool resource, with few restrictions on access.
• Rice-fields are breeding, spawning, feeding and growth
habitats for many fish and OAA
• Estimated 28% of the inland freshwater fisheries sector
• Rice-fish co-culture can also have significant benefits in
terms of rice production.
Water for a food-secure world
www.iwmi.org

4. Mutually exclusive policy
priorities?
• RCG’s Strategic Planning Framework for 2010-2020
– rice-field fisheries as a an essential component of national food
security strategies
– projected 15% annual increase in catch, to reach 0.5m tonnes by
2019 (compared to 0.11 m tonnes in 2000)
• Intensification of rice cultivation results in conditions less
favourable for fish and OAA
– increased use of agrochemicals
– changes in water management practices at field
– changes in habitat and barriers to fish migration due to
construction of irrigation infrastructure
Water for a food-secure world
www.iwmi.org

5. Impact of pesticides
• Pesticides the greatest threat to rice-field fish and OAA?
• Unregulated use of toxic pesticides banned in many
countries, such as organophosphates and
organochlorines (DDT); over- and mis-use is common
• 5-7 applications of pesticide in a season are not unusual
for dry season crops in Prey Veng
• Return of irrigation water to canals, streams and
groundwater - impacts not localised.
Water for a food-secure world
www.iwmi.org

6. Water management implications
• Changed in-field water regimes may impact viability of
rice-field fisheries
– catches are higher in sites that are deeper and inundated for
longer periods
• Little impact of irrigation on fisheries as long as wet
season rice-fields continue as deep-water systems
• Intensification often involves a shift from a long period
wet season crop to two shorter period crops and
reduction in period of continuous inundation
– expected to decrease overall aquatic productivity
– Impacts of alternate wetting and drying (AWD), System of Rice
Intensification (SRI)?
Water for a food-secure world
www.iwmi.org

7. Dams and infrastructure
• Construction of irrigation infrastructure (canals and dams)
changes riverine ecosystems.
– Impacts on biodiversity are almost always negative
• In theory, overall productivity at local scales may not be
affected, as reservoirs and canals can provide alternative
fishery
– In practice, problems with identifying and regulating access rights
e.g. reservoir is an open access & farmers closer to main canal can
block the canal and monopolize access to migrating fish
• Dams act as barriers to fish migration, and can result in very
significant decline in the population of migratory fish
– eg from 79 to 53 species after construction of the Stung Chinit
scheme, despite fish ladder
Water for a food-secure world
www.iwmi.org

8. Management and mitigation
• Reduction of pesticide use
– Law on Pesticide and Chemical Fertiliser Control 2011
– Education of farmers in proper use of pesticides
– Integrated pest management approaches?
– Use of the SRI, with reduced input of agro-chemicals
• In-field water management: better understanding is needed of
the impact of in-field water regimes on fish and OAA.
• In-field refuges: slot trenches in the field during AWD / SRI
Water for a food-secure world
www.iwmi.org

9. Management and mitigation
• Community refuge ponds (man-made or natural) - dry season
sanctuaries for brood fish; stock enhancement; fishing access
regulations (seasonal no-take zones)
• Reservoir and pond aquaculture
Water for a food-secure world
www.iwmi.org

10. Who gains, who loses?
• Gains from intensified rice production need to offset the
potential loss of rice-field fisheries to be beneficial in
aggregate terms.
• Intensification of rice benefits individual (mainly large
scale) farmers
• Rice-field fishery is a common pool resource, particularly
important for poor.
• Measures to mitigate loss of the rice-field fishery must go
beyond productivity, and consider the social distribution of
benefits
Water for a food-secure world
www.iwmi.org

11. Thank You.
Water for a food-secure world
www.iwmi.org