Abstract: A system, apparatus, and method for underwater self-contained and remotely controllable tagging of marine fauna involves emplacement of a tagging unit that can be used for example in a fishing trawl and establishment of communications with the unit through a cable wire that may be conventional. Numerous types of information can be recorded in relation to the tagging, including two- and/or three-dimensional images of the animal, to be used at a later date when the tagged animal is recovered. The method decreases tagging mortality and the biological effects of tagging on the animals, since they are not exposed to temperature and pressure changes, human handling and, at times, anesthesia. The embodiment makes it possible to tag deep-sea species that have never been tagged due to the fact that they would not survive the ambient changes of coming to the water's surface.