farms. Farmers mainly purchased these compounds in the chemical
supply shops or from salesmen visiting the farm. Some medium
and large scale tilapia farms used a portable sprayer to apply the
compound solution. Several shrimp farmers added seaweed extract
to enhance the binding of compounds to the feed pellets, because
shrimp, unlike tilapia that readily consume feed, require a much longer
time of up to 2 to 5 h to consume the feed with the risk that the
added compound would dissolve into the pond water. Only one
manager reported spraying antimicrobial solutions directly into the
pond water. Around half of the tilapia (14/25) and shrimp (13/30)
farm managers adjusted the chemical compound (antimicrobials,
disinfectants and anti-parasitic drugs) dosage based on the cultured
species mass and dosage instructions on the package labels. On the
large scale farms, medicated feed was prepared by workers under
the supervision of the technical manager. Six out of 25 (three
small, one medium and two large scale) tilapia farms kept written
records of their chemical use as compared to 12 of 30 shrimp farms
(four small, six medium and two large scale farms)