Development of real-time underwater acoustic equipment for deep sea survey

The marine litter is known as a major source of the destruction of the marine ecosystem and its components. Especially the problem caused by the derelict fishing nets is called the ghost fishing. In order to understand and to solve the problems raised by marine litters, we developed a practical and efficient real-time survey system for deep sea environment. This system consists of a guide frame called Tow-sled, a real-time deep-sea camera, position tracking devices and etc. The present paper shows the results of the development of the equipment to survey the marine litter such as fishing net in deep sea environment.