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oto Adventures

Rice vs fish

(only 35% produce surplus)

Sanjiv de SilvaMarch 19, 2013IWMI-ACIAR workshopPhnom Penh

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Objective & Discussion QuestionsObjective

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?

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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.

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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

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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.

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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)?

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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

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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

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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

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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

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Thank You.