Fish water productivity
A sinner’s view

Some observations

Fish stocks almost certainly under-estimated – even
in Mekong
1500 1,000
Cambodia 800
Laos
GVP, million $
GVP, million $
1000 600
400
500
200
0
0 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year
Year
Crop Livestock Fish low estimate
Crop Livestock Fisheries Fish - high estimate
5000
Thailand
5000
Vietnam
4000
GVP, million $
4000
GVP, million $
3000
3000
2000
2000
1000
1000
0
1995 1996 1997 1998 1999 2000 2001 2002 2003 0
Year 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Crop Livestock Fish low estimate Crop Year
Livestock Inland fisheries
Total Thai fish , Mekong agriculture

Ganges
1,167 bcm
Simple story
M eko ng
1,19 5 b cm
Sa o Fr a nc i s c o
622 bcm
Nile
2,042 bcm
Suppy limit
Capacity limit
1.0
Net runoff
Indus
Ganges
865 bcm
ET / ETot
p
Sao Francisco
Grassland ET
Fish
0.5 Mekong
Rainfed crops Lim popo
229 bcm Volta
Crops Capture fisheries
Nile
Irrigation ET Limpopo likely to be
Yellow River
Livestock important in wet
Karkeh Indus
Yellow
384 bcm
basins
Irrigation
Aquaculture
0.0 Andean
elsewhere –
0.00 0.50markets permitting
1.00 1.50 2.00
K ar kheh
2 1, 4 0 2 mcm
Rain / ETpot

Threats to fish stocks
• More flow more fish - Dai fishery in Tonle Sap river
• Expect flow changes (dams) to lead to decline in
yield

Smoking fish, a women activity
Valued-adding

Aquaculture more likely to meet expanding demand
Capture Aquaculture

‘water productivity’
• What we know
• What we don’t know

we know…
• …case studies showing fish CAN be
important
• Where present, fish provide special
support. Triple systems in Africa
– Fish, crops, cattle
• Fish under-reported in statistics
• 84%of global catch from 20 countries
– 10 Asia, 7 Africa
• Top 20 countries per capita fish catch
– 4 in Asia (but includes Cambodia), 13 in Africa

We don’t know
• If the concept of Wprod is useful for fish
– More akin to livestock
• Basic data on fish stocks
– Consumption data vs recorded catch
• How many people depend on fish
• What happens to fish stocks if hydrology
changes
• What alternatives exist if fish stock is
damaged

Are fish likely to be important?

Suggested structure
• To evaluate ‘water productivity’
– Aquaculture that uses water abstracted
• The most straightforward
– Aquaculture integrated into livestock / cropping
systems
• More complex trade-offs
– Capture fisheries
• Mainly about evaluating the over-looked

Some sources
• Some papers
– Martin van Brakel et al. 2008. Water Productivity
of fisheries.
– Maya Rajasekharan 2008. Towards an
understanding of fisheries water productivity
– David Blake. 2006.The Songkhram River wetlands
- A critical floodplain ecosystem of the Lower
Mekong Basin
– Chris Bene and Richard Friend. 2008. Water,
poverty and inland fisheries: Some lessons from
Africa and Asia.