Technical efficiency of black tiger prawn industry in Taiwan：panel data analysis

Abstract

The cost of feed is usually the greatest operating cost in aquaculture. Over feeding results in left over feed, which leads to not only the extra-cost, but also poor water quality, stress to the fish and an extra-load on the mechanical filters, biofilters and oxygenation equipment. Feeding management is as important as the design of the diet itself and knowing when to stop feeding is of great importance for successful feed management. Timer-controlled automatic feeders with a rotating plate and scrubber are widely used in the indoor re-circulating eel culturing industry in Taiwan. The device was designed to run at preset times for a preset duration with no other control. An intelligent feedback control system was developed. The gathering behavior of eels was observed by an infrared photoelectric sensor and converted to digital signals. The feeder equipped with such a sensor and governing control strategy is able to stop feeding according to the gathering behavior of eels. The control strategy contains six user-adjustable parameters with default values. If the sensor fails to detect the gathering behavior for three (default) consecutive trials, the feeder will stop feeding until the next wake-up, thus reducing the risk of polluting the water, etc.