Manta Tow is a survey technique whereby skin divers will towed slowly behind a boat, recording their observation of the reef below. Often, this can be done to survey large areas, with the boat generally trying to maintain a constant depth profile in its course. The observations are taken in 1-2 min cycles, and the route of the boat is tracked using GPS. Many government groups in Thailand, such as the Department of Marine and Coastal Resources, utilize this technique to survey the islands in the Gulf.