CAMBRIDGE, MA. -- Scientists have long known that marine mammals such aswhales and porpoises have distinctive vocalization sounds. Nowresearchers at MIT Sea Grant's Center for Fisheries Engineering arehoping that intercepting those distinctive sounds by a floating buoywill help save the endangered right whale.
On July 1 a new effort to save the species will start with theimplementation of a mandatory ship reporting system for right whales.Ships weighing more than 300 gross tons will be required to notify theU.S. Coast Guard when entering critical habitats in Cape Cod Bay and theGreat South Channel, as well as along the Florida/Georgia coasts. TheCoast Guard, in turn, will alert those ships as to the latestwhereabouts of right whales.
The reporting system was adopted by the United Nations' InternationalMaritime Organization last December at the urging of NOAA (NationalOceanic and Atmospheric Agency), the U.S. Coast Guard and theInternational Fund for Animal Welfare. Details of the United Statesimplementation efforts were detailed at a press briefing today (June 25)at the Boston U.S. Coast Guard Station by Secretary of Commerce WilliamDaley, Secretary of Transportation Rodney Slater and by Admiral James C.Card, Vice Commandant of the U.S. Coast Guard.
The northern right whale (Eubalaena glacialis) is the most endangeredlarge whale in the world, facing a high likelihood of extinction largelydue to human impacts on the species. The western North Atlanticpopulation, found off the eastern United States and Canada, is estimatedto contain less than 300 animals.
Although whaling is now illegal, right whales are still stronglyaffected by human activities, with approximately 30% of all mortalitiesresulting from collisions with large vessels or entanglement in fishinggear. When right whales breathe they produce a V-shaped blow that isoften 15 feet high. An adult right whale can measure up to 60 feet, andthe maximum weight is slightly more than 91 metric tons (100 tons). Anewborn calf can measure 15 feet at birth and weigh 2,000 pounds.
Currently, the principal source of sighting data is aircraftobservations, an approach that becomes unreliable at night and duringpoor visibility when the endangered whales are most vulnerable to shipstrikes. The system currently under development by MIT Sea Grant'sCenter for Fisheries Engineering Research (CFER) may just fill that gap.
CFER's director, Cliff Goudey, and research associate Ken Ekstrom, havedeveloped an acoustic detection buoy with funding support from theMassachusetts Environmental Trust and the National Fish and WildlifeFoundation.
Construction of a prototype unit is nearly complete, and it will betested this summer in Cape Cod Bay, Stellwagen Bank or in Canada's GrandManan Sanctuary. The device is a passive listening station housed in aslender spar buoy. It includes a submerged hydrophone, sophisticatedelectronics for differentiating right whale vocalizations from othersounds in the ocean, and a radio transmitter.
The MIT team intends to experiment with two modes of operation. Onemethod will simply send a time-stamped signal when a vocalization isheard, and would allow the fixing of a whale position if the voice washeard from more than one station. The second method will transmit thevocalization itself, and might allow scientists to identify individualwhales by analyzing their voice characteristics.
The initial tests will occur using HAM radio bands. If the systemproves valuable, specific frequencies could be set aside for an array ofbuoys that could monitor areas of concern. Although dependent onbackground noise levels, the researchers expect detection ranges ofabout five miles from a buoy.
An important aspect of the design is an ability to discriminate a rightwhale call from the myriad of other underwater sounds. To get thosesounds CFER's Ekstrom traveled to Canada's Grand Manan Sanctuary in theBay of Fundy where extensive recordings were made of right whalevocalizations.
"From these recordings we know that the right whale has distinctivevocalizations, though humpback sounds occur at similar frequencies,"says Ekstrom. "We hope our electronics will be sufficient to minimizefalse reports."
The project has been supported by NOAA's MIT Sea Grant program for thepast two years. According to Goudey, "Our goals is to provide acost-effective way to supplement the current techniques of visualobservations. Indeed, by keeping close track of the whales at night andduring fog, more efficient search patterns can be established oncevisibility improves.
"I do not see this as replacing the current visual spotting used by NOAAand the U.S. Coast Guard, but rather as a supplement. I suspect that theright whale is most vulnerable when darkness, or bad weather hampersvisibility. This should enable us to fill that gap."
Goudey plans to place the prototype buoy near areas where whales arespotted in late July and monitor it from a shore location. They willthen compare the data with sightings reported by NOAA and the CoastGuard. Says Goudey, "We'll base how well it works on comparison to datacurrently being supplied. Eventually we may be able to trackindividuals, but for now that is best left to visual tracking."
Materials provided by National Sea Grant College Program. Note: Content may be edited for style and length.
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