Once they get tangled, they panic, and a fight for life begins. If they cannot free themselves and surface to breathe, they will suffocate and die. If a dolphin is lucky and free himself, some of the net may stay attached to his body and hinder him in his movements. In the fight for life and death, the tangled dolphin may cause considerable damage the nets. For the fisherman it also means much work to get the dead dolphin out.
Dolphins are very smart but also very curious.
The idea was to develop an ultrasonic sound that would scare dolphins. Small transmitters could be attached to the fish nets. The scaring noise could keep the dolphins at a distance from the nets. A rechargeable battery pack provides the energy. It is all molded in plastic able to resist any pressure.