Underwater gliders are less conspicuous, costly and provide real-time alerts of whale interactions
Woods Hole Oceanographic Institution (WHOI) is the world’s largest private, not-for-profit oceanographic research institution. Its mission statement says that it is dedicated to research and education to advance understanding of the ocean and its interaction with the Earth system, and to communicating this understanding for the benefit of society.
WHOI is conducting a research project to listen to baleen whales. They are characterized by having baleen plates for filtering food from water, rather than having teeth. WHOI is using two underwater robots with instruments designed to “listen” for the calls of baleen whales. The gliders were equipped with a digital acoustic monitoring (DMON) instrument and specialized software. This allowed the researchers to listen for calls from four species, sei, fin, humpback and right whiles. Baumgartner designed special software that uses the spectrograms to generate a “pitch track,” a visual representation of a whale call that can predict which species of whale made the call. Spectrograms are a form of audio that facilitates complex sound analysis.
The research team is led by scientists Mark Baumgartner and Dave Fratantoni. The underwater robots that they are using are called gliders. They are battery powered and move extremely quietly through the water so as not to scare or alert the whales.
Last month in the Gulf of Maine, the gliders heard the call of nine endangered North American right whales. Shore-based researchers were alerted by the robots within hours of hearing the call. This was done in real-time demonstrating a new and powerful tool for managing interactions between whales and human activites.
Mark Baumgartner and Dave Fratantoni, reported their sightings to NOAA. National Oceanic (News - Alert) and Atmospheric Administration (NOAA) is a federal agency focused on the condition of the oceans and the atmosphere. After receiving the information, on December 5, 2012, NOAA put in place a "dynamic management area," asking mariners to voluntarily slow their vessel speed to avoid striking the animals.
The WHOI research project took place between November 12 and December 5, 2012 operating in an area called the Outer Fall, about sixty miles south of Bar Harbor, Me., and 90 miles northeast of Portsmouth, NH. Right whales are thought to use this area every year between November and January as a mating ground.
Normally visual based surveys are taken. This is accomplished from either a plane or a boat. You can imagine how much more effective it is to have the gliders in the water basically swimming with the whales. In addition to demonstrating the value of the robots for the management and conservation of baleen whales, the project also has ongoing scientific objectives, such as obtaining measurements and biological samples of the tiny crustaceans or zooplankton upon which the whales feed. “We wanted to figure out what right whales were feeding on in this area,” said Baumgartner.