Experts claim success with ‘green water’vs bacteria
Two University of the Philippines (UP) biotechnology experts have finally succeeded in battling the pesky luminous bacteria that have caused untold losses to shrimp growers.
Dr. Jesse D. Ronquillo of the National Institute of Molecular Biology and Biotechnology and Prof. Valeriano L. Corre, Jr. of the Institute of Aqualculture (IA), College of Fisheries and Ocean Sciences from the University of the Philippines in the Visayas (UPV) said their research has shown that using “green water” technology eliminates the bacteria that had caused high mortalities in prawn grow-out areas.
Research on the problem started in 1999 but the technology was perfected only in the last three years.
Ronquillo and Corre said the project aimed to prevent and control aquaculture diseases like the spread of vibrio or luminous bacteria, which broke out in 1993 and exterminated shrimps in Visayas farms.
Chlorination had long been used to reduce pathogens in the water but the impact was short-term since rapid repopulation of seawater occurred upon dechlorination.
Another method was to use vaccines and antibiotics but no vaccine has been available to eliminate most shrimp diseases. Moreover, the use of antibiotics is suspect since it can have collateral effects on consumers.
Modifications in management techniques were suggested to address the problem posed by luminous bacteria but the semi-intensive farming method and the use of modular ponds proved to be rather expensive and laborious.
Since the completion of the project in 2002, shrimp production has been enhanced.
The new technology uses green water to culture shrimps. It is a technique that relies on phytoplankton-rich water. In this system, saline tilapia is also propagated in fish cages to produce green water, which controls the growth of luminous bacteria.
Green water technology is the most functional solution, Ronquillo and Corre said.
Through this technique, pathogen growth can be inhibited, water quality can be improved and the immune system of the cultured species can be stimulated. The use of biocontrol agents like living microorganisms, aside from being a biological method, costs much less.
The propagation of green water technology is funded by the Bureau of Agricultural Research (BAR) through its biotechnology research and development (R&D) program.