David Mellinger - david.mellinger@oregonstate.edu
Associate Professor, Senior Research
Cooperative Institute for Marine Resources Studies Oregon State University
2030 S. Marine Science Drive
Newport, OR 97365 USA
Popular Version of Paper 5aAB1
Presented Friday morning, May 18, 2012
163rd ASA Meeting, Hong Kong
Researchers use sound to locate and track marine mammals. Often this has been done from hydrophones -- underwater microphones -- towed behind ships, which cover a large area but, because of expense, can only stay out for weeks to months at a time. Another method that has grown in popularity in the last two decades is autonomous monitoring, in which a hydrophone recorder is placed on the sea floor. For up to two years, it listens to ambient acoustic time, after which it is recovered. Autonomous recorders last a long time but survey from only a single point in the ocean. In both cases, software for automatically detecting whale and dolphin calls is crucial for handling the large quantity of data received.
Now some new platforms are emerging. The first, the ocean glider, uses buoyancy changes to move up and down in the water; wings convert this vertical traversal into horizontal motion, enabling it to travel long distances over long periods of time at low cost. Each time the glider reaches the surface, it makes a satellite phone call to shore to report what marine mammal calls were automatically detected. It can also receive new operating directions during this phone call. We collaborated with researchers at the Applied Physics Laboratory, University of Washington to use an acoustically equipped ocean glider to survey areas offshore the Island of Hawaii and offshore Andros Island in the Bahamas. We successfully detected our target species, a type of beaked whale, as well as a several other cetacean species.
An autonomous float is also driven by buoyancy changes, but it does not try to move forward; instead, it simply parks itself on the sea floor or, in deeper water, drifts with deep currents. Our autonomous float, the QUEphone, successfully detected beaked whales in the same two field trials in Hawaii and the Bahamas, and also detected them in another test offshore southern California.
The robotic sailboat is an entirely different beast. Driven by the wind, it uses a sophisticated control system to control sails and rudder to steer the craft in any wind conditions. We are collaborating with Austrian Society for Innovative Computer Science to equip a robotic sailboat with an acoustic recording and detection system to perform acoustic surveys for marine mammals. Results of preliminary tests will be shown.