Using Radio-Acoustic Positioning and Telemetry (RAPT) to Define and Assess Marine Protected Areas (MPAs)

Abstract

Radio-acoustic positioning telemetry (RAPT) continuously triangulates positions of up to eight acoustic transmitters by relaying sound arrival times to a shore-based computer via autonomous, moored radio-sonobuoys. As transmitters on animals or people telemeter information via RAPT, it records their position with an accuracy of as little as one meter in as much as a cubic kilometer of water from a range of up to ten kilometres—scales appropriate to many marine protected areas (MPAs). RAPT studies in Lizard Island, Australia; Exuma Cay Park, Bahamas; Moriye Bay, Japan, and Leigh Laboratory Reserve, New Zealand, four significant MPAs, are reviewed showing the power of the technology for understanding and managing many aspects of a range of biological reserve types. Most studies to date have focused on monitoring fish (Lutjanus carponotatus, Lutjanidae; Plectropomus leopardus, Serranidae; Epinephelus striatus, Serranidae; Pagrus auratus, Sparidae) home ranges and migrations, but breeding and feeding behaviours of larger invertebrates such as horseshoe crabs (Tachypleus tridentatus, Limulidae) and squids (Sepioteuthis lessonianna and Loligo vulgaris, Loliginidae) have also been examined. RAPT systems can also record environmental changes in real-time directly to the computer on shore for such variables as temperature, salinity, tide height, current direction and current speed from fixed-position transmitters; these are easily compared to animal activities. Tracking tagged divers or ROVs while they are videotaping provides an accurate and reproducible way of documenting long-term changes in the sessile organisms that make up benthic habitats; only the buoy moorings need remain in the water between surveys. Finally, the location and condition of diving tourists can be monitored, to protect both them and the environment!