The DiD (Dolphin interactive Deterrent) is an equipment able to keep the dolphins away from fishing nets, thanks to an efficient technique of interaction with their echo-localization system (sonar).
The DiD is the interactive evolution of the standard DDD 03 models. It produces the ultrasounds only when it detects the presence of the dolphins in the area, by means of its “hearing” circuitry, that is activated by the “clicks” emitted by the mammals.
It is powered by internal (sealed) rechargeable batteries and generates an acoustic signal in case of insufficient charge.
The advantages of this model in comparison with the DDDs are the reduction of the possibility that dolphins become accustomed to the signals, the increased duration of the battery charge and the reduction of the acoustic pollution.
The level of the DiD emissions doesn’t produce any harm to mammals or fish; these last are insensitive to the frequencies emitted.