 |
||
 |
 |
 |
|
|
|||||||
|---|---|---|---|---|---|---|---|
|
|||||||
This report provides basic descriptive information concerning the way
aquaculture is practiced in four CRSP countries. It focuses on four central
aspects of tilapia culture; pond management, feeding, fertilization, and
stocking practices. Data were collected from tilapia growers: 121 active Rwanda
fish farmers in eight local administrative districts (communes) during the
winter and early spring of 1992; 51 active Honduran fish farmers in five of
15 Honduran departments during the fall 1993; 51 active Thai fish farmers in
four of 75 Thai provinces during winter 1994; 56 Philippine fish farmers in
four of 15 provinces on the main island of Luzon during winter 1994. In each
country, the survey instrument was revised and adapted, then translated into
the national language. More than 80 percent of the Rwandan farmers had but a
single pond. In contrast, more than 70 percent of the Philippine and Honduran
farmers had more than one pond. Most Honduran farmers had more that a hectare
of ponds. More than half the Thai sample reported problems getting enough water
to keep ponds full. A third of the Philippine farmers said so, as did a quarter
of the Rwandans. Farmers in the four countries fed their tilapia a variety of
different items reflecting differences in the intensity of aquaculture practice
in each nation. Commercial feed was not used in Rwanda; two-thirds
of the Hondurans did not use commercial feed; and about half the Philippine
respondents did not use commercial feed. Thai farmers were most dependent on
commercial inputs to raise their tilapia crops. They also used the most diverse
variety of feeds, reflecting the high level of availability of different feed
types and a greater willingness to use feeds for other animals for the fish as
well. Honduran and Rwandan farmers were most likely to report inadequacies in
feed availability on their farms. About seven percent of the Rwandan farmers
said that they never had enough. Cattle and goats were most often reported in
Rwanda, pigs in Honduras, and chickens in the Philippines, and ducks were more
frequent on Thai farms. Given the pervasive use of integrated systems in
Thailand, ponds are most frequently fertilized by animal manure in that
country. Thai farmers also are more likely to apply lime to improve the
alkaline balance of the pond and foster primary productivity. Rwandan farmers
indicated the most passive approach to fish farming - about half said they
visited every day. Philippine farmers spent the most time with their ponds when
they visited them; Thai farmers the least. Fingerling availability was a
problem for 30 percent of the Philippine respondents, less than 25 percent in
Rwanda and Honduras, and a concern for only 4 percent in Thailand. Most farmers
are growing but single crop of tilapia each year in Rwanda and Thailand. In
Honduras, almost half reported two or more crops, but in the Philippines two-thirds
obtained two crops per year. The data emanating from this study present a
comparative perspective on tilapia culture in four CRSP countries. The
similarities and differences suggest different patterns of technology
utilization and need in each setting. The benefits of these understandings
should help shape research directions and enhance the development impacts of
CRSP technologies.
Decision support systems are a useful mechanism for synthesizing qualitative
and quantitative knowledge into analysis tools that can easily be used by a
diverse audience. A user-friendly decision support system (POND) which can be
used to guide decision-making processes relevant to pond aquaculture management
and planning has been developed. POND uses a combination of expertise, an
economics package, and simulation models for analyzing pond aquaculture
systems, either at the level of an individual pond or for an overall facility.
This functionality is accomplished by the use of an object-oriented paradigm
which enables the definition of objects responsible for certain tasks analogous
to entities or experts in a real pond aquaculture facility (e.g., a fish
culturist) responsible for monitoring fish growth). The economics package can
be used to generate enterprise budgets, which account for fixed and variable
costs, depreciation, interest, and income items. Users can examine various pond
management strategies and generate enterprise budgets to assess the economic
viability of such strategies.POND includes simulation models to describe the dynamics of
fish growth, water
temperature, carbon, nitrogen and phosphorus, phytoplankton, and zooplankton.
These models are organized hierarchically into two levels to provide users with
the capability of performing different kinds of analyses based on data
availability and output resolution needs. The fish growth model accounts for
the effects of fish weight, food availability, photoperiod, temperature, and
dissolved oxygen and unionized ammonia concentrations, and has been calibrated
for Nile tilapia. This model has been used to simulate PD/A CRSP experiments at
different sites with favorable results. Simulation models that are used in POND
to describe other state variables are briefly discussed. The Pond Dynamics/Aquaculture CRSP is funded under USAID Grant No. LAG-G-00-96-90015-00
and by
the participating US and Host Country institutions.
Questions for or about the Aquaculture CRSP? Comments about this site? Email ACRSP@oregonstate.edu.
POND: A Decision Support System for Pond Aquaculture
Abstract
Disclaimers
