well as the low-priced fish species such as tilapia, mud carp and silver barb, are
typically consumed within the household, while the higher-priced grass carp is often
marketed. On average, self-recruiting species made up approximately 3 % of the
total live biomass output of aquatic species during the study, whereas the grass carp
accounted for over half (~52 %). The high proportion of grass carp in this pond
system is a result of its ability to use the available on-farm crop residues as major
feed inputs, as well as its ability to grow rapidly. It can also be sold at relatively high
prices. Unfortunately, frequently occurring grass carp diseases have led to high fish
mortality rates in the region in recent years, and around 70 % of fish farmers
interviewed said they had had to cope with this problem in previous years, with
some farmers reporting losses of their entire stocks. So far, the causative pathogen
involved has not been identified. Furthermore, techniques applied by farmers in
order to effectively prevent diseases or cure fish have so far failed. The grass carp
disease is probably the most important restriction in this grass-carp-dominated
aquaculture system, so within the framework of the Uplands Program, research
aimed at diagnosing and preventing this disease, as well as treating it, has also
been undertaken (see Sect. 8.7).
Despite the loss of grass carp, it has been shown that fish production is still a
lucrative business due to the low cost of pond inputs – since usually no off-farm
inputs are required except fish seed, the low opportunity costs for labor and
the relatively high fish prices. That fish is a high-valued commodity can be
shown when comparing the average local price for fish of approximately 1.2 USD
per kg (year 2005) with the average monthly per capita income of approximately
11.8 USD in Son La province (GSO 2004; 1 USD ¼ 18,000 Vietnamese dong).
The interviewed farmers reported that their mean income per household (with an
average of 5 members) had been almost 831 USD for the year 2004, of which
approximately 12 % was derived from sales of aquatic products. However, this
percentage was calculated using data from those farmers who also did not sell any
fish during the year under consideration.
In general, case study farmers produce fish for both income generation and home
consumption. Farmers obtain a high share of their protein intake from aquatic
products, and these products make an important contribution to farmers’ nutrient
intake and especially their supply of animal protein (Steinbronn 2009). It is widely
acknowledged that fish and other living aquatic resources can constitute an important component of the human diet; they are considered to be nutrient-dense foods
which provide protein, amino acids, fatty acids, minerals and vitamins (Prein and
Ahmed 2000). While in the past fish production in the study area was predominantly for subsistence purposes, the system has now become increasingly marketorientated, with fish the third most important product for the farmers in terms of
income generation after maize and cassava.
The demand for fish in the local market in Yen Chau cannot currently be
completely satisfied by the local fish production alone. In the years 2003–2005,
a road was upgraded to connect the north-western mountains with the country’s
capital Hanoi. As a result, fish from the more intensive aquaculture areas in the
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J. Pucher et al.
typically consumed within the household, while the higher-priced grass carp is often
marketed. On average, self-recruiting species made up approximately 3 % of the
total live biomass output of aquatic species during the study, whereas the grass carp
accounted for over half (~52 %). The high proportion of grass carp in this pond
system is a result of its ability to use the available on-farm crop residues as major
feed inputs, as well as its ability to grow rapidly. It can also be sold at relatively high
prices. Unfortunately, frequently occurring grass carp diseases have led to high fish
mortality rates in the region in recent years, and around 70 % of fish farmers
interviewed said they had had to cope with this problem in previous years, with
some farmers reporting losses of their entire stocks. So far, the causative pathogen
involved has not been identified. Furthermore, techniques applied by farmers in
order to effectively prevent diseases or cure fish have so far failed. The grass carp
disease is probably the most important restriction in this grass-carp-dominated
aquaculture system, so within the framework of the Uplands Program, research
aimed at diagnosing and preventing this disease, as well as treating it, has also
been undertaken (see Sect. 8.7).
Despite the loss of grass carp, it has been shown that fish production is still a
lucrative business due to the low cost of pond inputs – since usually no off-farm
inputs are required except fish seed, the low opportunity costs for labor and
the relatively high fish prices. That fish is a high-valued commodity can be
shown when comparing the average local price for fish of approximately 1.2 USD
per kg (year 2005) with the average monthly per capita income of approximately
11.8 USD in Son La province (GSO 2004; 1 USD ¼ 18,000 Vietnamese dong).
The interviewed farmers reported that their mean income per household (with an
average of 5 members) had been almost 831 USD for the year 2004, of which
approximately 12 % was derived from sales of aquatic products. However, this
percentage was calculated using data from those farmers who also did not sell any
fish during the year under consideration.
In general, case study farmers produce fish for both income generation and home
consumption. Farmers obtain a high share of their protein intake from aquatic
products, and these products make an important contribution to farmers’ nutrient
intake and especially their supply of animal protein (Steinbronn 2009). It is widely
acknowledged that fish and other living aquatic resources can constitute an important component of the human diet; they are considered to be nutrient-dense foods
which provide protein, amino acids, fatty acids, minerals and vitamins (Prein and
Ahmed 2000). While in the past fish production in the study area was predominantly for subsistence purposes, the system has now become increasingly marketorientated, with fish the third most important product for the farmers in terms of
income generation after maize and cassava.
The demand for fish in the local market in Yen Chau cannot currently be
completely satisfied by the local fish production alone. In the years 2003–2005,
a road was upgraded to connect the north-western mountains with the country’s
capital Hanoi. As a result, fish from the more intensive aquaculture areas in the
288
J. Pucher et al.