Aquaculture CRSP 21st Annual Technical Report
Survey of Tilapia-Shrimp Polycultures in the Philippines
Tenth Work Plan, New Species/New Systems Research 3E (10NSR3E)
Department of Soil, Water, and Environmental Science
University of Arizona
Tucson, Arizona, USA
Remedios B. Bolivar and JunRey R. Sugue
Freshwater Aquaculture Center
Central Luzon State University
Nueva Ecija, Philippines
A survey of farmers who had adopted some form of shrimp-finfish polyculture was conducted. The respondents included producers from 13 separate provinces in eight regions of the Philippines. Four separate techniques were reported for rearing fish with their shrimp: simultaneous, sequential, rotational, and cages inside ponds. The majority of the respondents stocked tilapia with shrimp, with milkfish being the primary alternative.
Most of the respondents reported that the integration of finfish and shrimp culture lessened disease problems, especially vibriosis. Several on-farm trials have shown that luminous bacterial counts in the water and in the shrimp were below 10 colony forming units (cfu) per ml and below 1,000 cfu per hepatopancreas, respectively. The on-farm trials were conducted in ponds that had previously been used for tilapia culture (rotation) and whose water was previously taken from a tilapia reservoir (sequential), as well as the stocking of tilapia in cages with shrimp (cages) and stocking directly in the ponds (simultaneous). Several of the respondents also reported that the tilapia contributed to "conditioning" the water. Specifically, the density of green algae increased, providing "greenwater."
The Philippines has developed the most wide-ranging forms of integrated tilapia-shrimp farming. The severe impact of diseases on the yield and profitability of shrimp culture provided much of the impetus for this variety. Adoption of polyculture has provided jobs for many people who had lost positions with the loss of shrimp operations and has led to what appears to an apparently more sustainable culture method.
Shrimp ponds have been abandoned in many parts of the world due to diseases, poor management, and environmental degradation. Production of tilapia, supplemented with low densities of shrimp may provide an opportunity to develop a sustainable aquaculture system using abandoned shrimp ponds that will support local Filipino inhabitants who have not benefited from the shrimp boom that has occurred in many parts of the world. Polyculture, or crop rotation of shrimp and tilapia, may even be the modern equivalent of the Chinese polyculture of carp. Tilapia production in former shrimp ponds (with and without shrimp) has increased rapidly in Aquaculture CRSP countries, including Thailand, the Philippines, Honduras, Mexico, Peru, and elsewhere, such as the inland desert of Arizona.
The spread of shrimp-tilapia polyculture presents a unique
opportunity to take advantage of the strengths of the Aquaculture CRSPÕs locations and expertise to conduct cross-cutting research and make a contribution to groups who would be most likely to understand and benefit from a sustainable production system. Farmers in several locations around the world appear to have demonstrated that tilapia and shrimp can be grown together.
Shrimp aquaculture has been devastated in many countries due to disease outbreaks or decreasing yields or both. The progression of shrimp aquaculture has followed a familiar pattern throughout the tropics. Initially, farms are constructed in the most appropriate areas. These locations are characterized by good soils with proper pH, appropriate levels of clay, silt, and sand, proper elevation, good access