of fish diseases occurring. These modifications were widely implemented, for
farmers had observed that the mortality and morbidity rates among grass carp
were linked to turbidity in the ponds, especially after heavy rain. However, these
modifications were not understood as measures that would increase primary production levels. Though farmers consider green water as being better for fish culture
than turbid pond water, most farmers do not know that greener water is linked to
higher natural food resources and higher oxygen production levels. Farmers have
traditionally applied organic fertilizer, such as buffalo manure, which is seen as a
direct feed source for the fish rather than a means of supporting the development of
green water. In addition, a basic knowledge of biology and nutritional requirements
of the cultured fish species is very sparse; farmers usually do not know the specific
feed resources available for the different stocked fishes under their traditional
polyculture system, except in the case of fish such as grass carp, which feed directly
on the materials applied by the farmers themselves. Natural food resources such as
phytoplankton, zooplankton and zoobenthos, and their importance for each specific
fish species, are generally not understood. Consequently, investment in the chemical fertilization of ponds is not seen by farmers as a means of providing internal
food for the fish and is, therefore, not accepted.
Owing to the limited financial savings to be found among most Black Thai
households, regular expenditure on farm resources with a market value, such as
chemical fertilizers or ingredients for the preparation of pellets for daily feeding
activities, is generally only adopted by the better educated and wealthier farmers,
whose incomes are more stable than those of the typical Black Thai households, and
who are, moreover, willing to invest in innovations that concentrate on aquaculture.
Another important factor limiting the adoption of the proposed modification to
the system is the almost total absence of record-keeping, for farmers rarely keep
track of basic labor times and expenditures, nor of (non-)marketed outputs, in order
to calculate overall financial benefits. These deficiencies in book-keeping make it
impossible for farmers to compare losses against gains for a single farm activity, or
to carry out overall cost/benefit calculations.
Furthermore, the ability of farmers to adopt new technologies and adapt them to
local circumstances is limited by a lack of both basic biological and economic
understanding.
In the pilot study, application of the entire set of proposed modifications was
shown to multiply the financial net return from pond aquaculture when compared
with the traditional system (Pucher et al. 2010a), thereby, turning local aquaculture
into a semi-intensive and more valid business. However, these modifications were
seen as a rather radical innovation for Black Thai farmers (Acharya et al. 2011),
because they require a constant investment of time and financial resources, which
does not fit well into the seasonal pattern of work and budget of a typical Black Thai
household. During the 3 years of collaboration, farmers had the chance to acquire
knowledge on aquaculture through practically daily contact with researchers, as
well as during workshops held on fish biology and general aquaculture. But it was
only the trial farmers who chose aquaculture as one of their key farming activities
that showed an increase in knowledge and disseminated it to their peers, whilst,
8 Improved Sustainable Aquaculture Systems for Small-Scale Farmers . . .
305
farmers had observed that the mortality and morbidity rates among grass carp
were linked to turbidity in the ponds, especially after heavy rain. However, these
modifications were not understood as measures that would increase primary production levels. Though farmers consider green water as being better for fish culture
than turbid pond water, most farmers do not know that greener water is linked to
higher natural food resources and higher oxygen production levels. Farmers have
traditionally applied organic fertilizer, such as buffalo manure, which is seen as a
direct feed source for the fish rather than a means of supporting the development of
green water. In addition, a basic knowledge of biology and nutritional requirements
of the cultured fish species is very sparse; farmers usually do not know the specific
feed resources available for the different stocked fishes under their traditional
polyculture system, except in the case of fish such as grass carp, which feed directly
on the materials applied by the farmers themselves. Natural food resources such as
phytoplankton, zooplankton and zoobenthos, and their importance for each specific
fish species, are generally not understood. Consequently, investment in the chemical fertilization of ponds is not seen by farmers as a means of providing internal
food for the fish and is, therefore, not accepted.
Owing to the limited financial savings to be found among most Black Thai
households, regular expenditure on farm resources with a market value, such as
chemical fertilizers or ingredients for the preparation of pellets for daily feeding
activities, is generally only adopted by the better educated and wealthier farmers,
whose incomes are more stable than those of the typical Black Thai households, and
who are, moreover, willing to invest in innovations that concentrate on aquaculture.
Another important factor limiting the adoption of the proposed modification to
the system is the almost total absence of record-keeping, for farmers rarely keep
track of basic labor times and expenditures, nor of (non-)marketed outputs, in order
to calculate overall financial benefits. These deficiencies in book-keeping make it
impossible for farmers to compare losses against gains for a single farm activity, or
to carry out overall cost/benefit calculations.
Furthermore, the ability of farmers to adopt new technologies and adapt them to
local circumstances is limited by a lack of both basic biological and economic
understanding.
In the pilot study, application of the entire set of proposed modifications was
shown to multiply the financial net return from pond aquaculture when compared
with the traditional system (Pucher et al. 2010a), thereby, turning local aquaculture
into a semi-intensive and more valid business. However, these modifications were
seen as a rather radical innovation for Black Thai farmers (Acharya et al. 2011),
because they require a constant investment of time and financial resources, which
does not fit well into the seasonal pattern of work and budget of a typical Black Thai
household. During the 3 years of collaboration, farmers had the chance to acquire
knowledge on aquaculture through practically daily contact with researchers, as
well as during workshops held on fish biology and general aquaculture. But it was
only the trial farmers who chose aquaculture as one of their key farming activities
that showed an increase in knowledge and disseminated it to their peers, whilst,
8 Improved Sustainable Aquaculture Systems for Small-Scale Farmers . . .
305