Abstract: The invention is a system comprising a wire cage crustacean trap coupled to a remotely controlled subsystem operative to receive a control-coded acoustic signal and thereupon open an electrically controlled pneumatic valve allowing gas under pressure to be conveyed to a deflated bladder, such that the bladder inflates and brings the system to the surface. Backup systems will cause the valve to open when a preprogrammed time duration has elapsed and/or when a water leak is detected inside the remotely controlled subsystems water-tight container.

Abstract: The invention is a system that enables passive sonar identification of underwater items by making use of lift bags and/or flags, having distinctive sequences of bands of sonar-signal-reflecting materials, wherein the lift items are partially inflated so as to present a predictable orientation with respect to the floor of a body of water and its surface.

Abstract: The invention is a system comprising a wire cage trap and wire-cage enclosed lifting subsystem. The two systems are attached and submerged together. When ready to be retrieved, a sound control signal is conveyed to the system. The sound control signal is converted to an electric control signal, which enables inflation of a buoyancy bladder and bringing the wire-cage trap and wire-cage lifting subsystems to the surface. The invention may comprise sensors in the lifting system which can provide information about valve on-off state, gas pressure, depth and location. That information is converted from electric to sound signals and generated through the water.