Fish water productivity

A sinner’s view

Some observations

0

1000

2000

3000

4000

5000

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

GVP, million $

Crop Livestock Inland fisheries

0

500

1000

1500

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003Year

GVP, million $

Crop Livestock Fisheries Fish - high estimate

0

1000

2000

3000

4000

5000

1995 1996 1997 1998 1999 2000 2001 2002 2003Year

GVP, million $

Crop Livestock Fish low estimate

0

200

400

600

800

1,000

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

GVP, million $

Crop Livestock Fish low estimate

Fish stocks almost certainly under-estimated – even

in Mekong

Total Thai fish , Mekong agriculture

Cambodia

Thailand

Laos

Vietnam

Simple story

Andean0.0

0.5

1.0

0.00 0.50 1.00 1.50 2.00

Rain / ETpot

ET / ET pot

Capacity limit

Suppy limit

Ganges

Mekong

Sao Francisco

Volta

Yellow River

NileLimpopo

IndusKarkeh

Fish

Livestock

Crops

Irrigation

M ekong

1,19 5 bcm

Ganges

1,167 bcm

K a r kh eh

2 1 , 4 0 2 mcm

Irrigation ET

Yellow

384 bcm

Rainfed cropsLimpopo

229 bcm

Grassland ET

Indus

865 bcm

Net runoff

Nile

2,042 bcm

Sa o F r a n c i s c o

6 2 2 b c m

Capture fisheries

likely to be

important in wet

basins

Aquaculture

elsewhere –

markets permitting

Threats to fish stocks

• More flow more fish - Dai fishery in Tonle Sap river

• Expect flow changes (dams) to lead to decline in

yield

Valued-addingSmoking fish, a women activity

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.