annual fish yields are relatively low, at only 1.5 tons per ha per year, as compared to
other integrated carp polyculture systems in northern Vietnam which have reported
yields up to 6.7 tons per ha (Red River delta) (Luu et al. 2002). Nevertheless,
Steinbronn (2009) showed that aquaculture production contributes significantly to
food security, generates income and plays a significant role in farmers’ livelihood
strategies. The aim of her study was to provide a detailed and holistic understanding
of the actual aquaculture system used and, in the second phase, to create tailor-made
location-specific solutions that would have the potential to improve the livelihoods
of farmers in an economically, socially and ecologically sustainable way. Data were
collected between 2003 and 2006 based on interviews with fish farmers, village
headmen and other stakeholders, as well as through an in-depth investigation of
individually selected case study farms. Here, resource flows to and from the pond
system were monitored quantitatively. The most important features of this aquaculture system are summarized in the following part of this section.
As stated in Chap. 1, more than half of the district’s population is of Black Thai
ethnicity; settled in highland valleys and along the banks of rivers or streams, where
paddy rice is cultivated. Rice is the major food crop in this region and is predominantly used for subsistence, while maize and cassava are the main rain-fed crops –
planted on hillsides as cash crops. Bananas and occasionally cotton are planted in
the upland fields, while fruits and vegetables are primarily produced in home
gardens. The common livestock raised here include buffalos, cattle, goats, pigs
and poultry. The mean farm size of the farmers interviewed for the study was
around 1.7 ha, of which paddy fields accounted for approximately 11 % and ponds
9 %. Around 63 % of the households in the study area owned one or more ponds and
produced fish.
Although aquaculture production has a long history in northern Vietnam
(Edwards et al. 1996), aquaculture activities in the study area are a relatively recent
phenomenon, and about half the farmers interviewed stated they had dug their
ponds within the previous two decades.
The average size of the ponds was found to be around 800 m
2 , most being
earthen. Dykes were concreted only rarely, but surrounded by trees such as bamboo
or fruit trees. Some pond embankments also served as vegetable production areas.
Almost all the farmers had placed tree branches in their ponds to prevent angling or
the use of nets by thieves, as theft is a widespread problem, especially in those
ponds located far from farmers’ houses.
Typically, ponds were constructed either in series or in parallel, and water flows
through the ponds by means of gravity. The water in those ponds located in the
valleys was usually supplied from the shared irrigation system. Activities carried
out by individual farmers, such as the application of pesticides in paddy fields
(Lamers et al. 2011) or even the practice of washing clothes in the canals (Alcaraz
et al. 1993) may have had an influence on connected ponds in a negative way.
Fish are ecto-thermal animals, so water temperature strongly influences their
growth and well-being. The ideal temperature range for fish culture is generally
above 25
C for most warm-water Asian fish (Cagauan 2001) and feeding activity
tends to decrease or stop at temperatures below 20
C (Ling 1977). Whereas the
284
J. Pucher et al.
other integrated carp polyculture systems in northern Vietnam which have reported
yields up to 6.7 tons per ha (Red River delta) (Luu et al. 2002). Nevertheless,
Steinbronn (2009) showed that aquaculture production contributes significantly to
food security, generates income and plays a significant role in farmers’ livelihood
strategies. The aim of her study was to provide a detailed and holistic understanding
of the actual aquaculture system used and, in the second phase, to create tailor-made
location-specific solutions that would have the potential to improve the livelihoods
of farmers in an economically, socially and ecologically sustainable way. Data were
collected between 2003 and 2006 based on interviews with fish farmers, village
headmen and other stakeholders, as well as through an in-depth investigation of
individually selected case study farms. Here, resource flows to and from the pond
system were monitored quantitatively. The most important features of this aquaculture system are summarized in the following part of this section.
As stated in Chap. 1, more than half of the district’s population is of Black Thai
ethnicity; settled in highland valleys and along the banks of rivers or streams, where
paddy rice is cultivated. Rice is the major food crop in this region and is predominantly used for subsistence, while maize and cassava are the main rain-fed crops –
planted on hillsides as cash crops. Bananas and occasionally cotton are planted in
the upland fields, while fruits and vegetables are primarily produced in home
gardens. The common livestock raised here include buffalos, cattle, goats, pigs
and poultry. The mean farm size of the farmers interviewed for the study was
around 1.7 ha, of which paddy fields accounted for approximately 11 % and ponds
9 %. Around 63 % of the households in the study area owned one or more ponds and
produced fish.
Although aquaculture production has a long history in northern Vietnam
(Edwards et al. 1996), aquaculture activities in the study area are a relatively recent
phenomenon, and about half the farmers interviewed stated they had dug their
ponds within the previous two decades.
The average size of the ponds was found to be around 800 m
2 , most being
earthen. Dykes were concreted only rarely, but surrounded by trees such as bamboo
or fruit trees. Some pond embankments also served as vegetable production areas.
Almost all the farmers had placed tree branches in their ponds to prevent angling or
the use of nets by thieves, as theft is a widespread problem, especially in those
ponds located far from farmers’ houses.
Typically, ponds were constructed either in series or in parallel, and water flows
through the ponds by means of gravity. The water in those ponds located in the
valleys was usually supplied from the shared irrigation system. Activities carried
out by individual farmers, such as the application of pesticides in paddy fields
(Lamers et al. 2011) or even the practice of washing clothes in the canals (Alcaraz
et al. 1993) may have had an influence on connected ponds in a negative way.
Fish are ecto-thermal animals, so water temperature strongly influences their
growth and well-being. The ideal temperature range for fish culture is generally
above 25
C for most warm-water Asian fish (Cagauan 2001) and feeding activity
tends to decrease or stop at temperatures below 20
C (Ling 1977). Whereas the
284
J. Pucher et al.