June 29, 1999 CAMBRIDGE, MA. -- Scientists have long known that marine mammals such as whales and porpoises have distinctive vocalization sounds. Now researchers at MIT Sea Grant's Center for Fisheries Engineering are hoping that intercepting those distinctive sounds by a floating buoy will help save the endangered right whale.
On July 1 a new effort to save the species will start with the implementation of a mandatory ship reporting system for right whales. Ships weighing more than 300 gross tons will be required to notify the U.S. Coast Guard when entering critical habitats in Cape Cod Bay and the Great South Channel, as well as along the Florida/Georgia coasts. The Coast Guard, in turn, will alert those ships as to the latest whereabouts of right whales.
The reporting system was adopted by the United Nations' International Maritime Organization last December at the urging of NOAA (National Oceanic and Atmospheric Agency), the U.S. Coast Guard and the International Fund for Animal Welfare. Details of the United States implementation efforts were detailed at a press briefing today (June 25) at the Boston U.S. Coast Guard Station by Secretary of Commerce William Daley, 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 endangered large whale in the world, facing a high likelihood of extinction largely due to human impacts on the species. The western North Atlantic population, found off the eastern United States and Canada, is estimated to contain less than 300 animals.
Although whaling is now illegal, right whales are still strongly affected by human activities, with approximately 30% of all mortalities resulting from collisions with large vessels or entanglement in fishing gear. When right whales breathe they produce a V-shaped blow that is often 15 feet high. An adult right whale can measure up to 60 feet, and the maximum weight is slightly more than 91 metric tons (100 tons). A newborn calf can measure 15 feet at birth and weigh 2,000 pounds.
Currently, the principal source of sighting data is aircraft observations, an approach that becomes unreliable at night and during poor visibility when the endangered whales are most vulnerable to ship strikes. The system currently under development by MIT Sea Grant's Center for Fisheries Engineering Research (CFER) may just fill that gap.
CFER's director, Cliff Goudey, and research associate Ken Ekstrom, have developed an acoustic detection buoy with funding support from the Massachusetts Environmental Trust and the National Fish and Wildlife Foundation.
Construction of a prototype unit is nearly complete, and it will be tested this summer in Cape Cod Bay, Stellwagen Bank or in Canada's Grand Manan Sanctuary. The device is a passive listening station housed in a slender spar buoy. It includes a submerged hydrophone, sophisticated electronics for differentiating right whale vocalizations from other sounds in the ocean, and a radio transmitter.
The MIT team intends to experiment with two modes of operation. One method will simply send a time-stamped signal when a vocalization is heard, and would allow the fixing of a whale position if the voice was heard from more than one station. The second method will transmit the vocalization itself, and might allow scientists to identify individual whales by analyzing their voice characteristics.
The initial tests will occur using HAM radio bands. If the system proves valuable, specific frequencies could be set aside for an array of buoys that could monitor areas of concern. Although dependent on background noise levels, the researchers expect detection ranges of about five miles from a buoy.
An important aspect of the design is an ability to discriminate a right whale call from the myriad of other underwater sounds. To get those sounds CFER's Ekstrom traveled to Canada's Grand Manan Sanctuary in the Bay of Fundy where extensive recordings were made of right whale vocalizations.
"From these recordings we know that the right whale has distinctive vocalizations, though humpback sounds occur at similar frequencies," says Ekstrom. "We hope our electronics will be sufficient to minimize false reports."
The project has been supported by NOAA's MIT Sea Grant program for the past two years. According to Goudey, "Our goals is to provide a cost-effective way to supplement the current techniques of visual observations. Indeed, by keeping close track of the whales at night and during fog, more efficient search patterns can be established once visibility improves.
"I do not see this as replacing the current visual spotting used by NOAA and the U.S. Coast Guard, but rather as a supplement. I suspect that the right whale is most vulnerable when darkness, or bad weather hampers visibility. This should enable us to fill that gap."
Goudey plans to place the prototype buoy near areas where whales are spotted in late July and monitor it from a shore location. They will then compare the data with sightings reported by NOAA and the Coast Guard. Says Goudey, "We'll base how well it works on comparison to data currently being supplied. Eventually we may be able to track individuals, but for now that is best left to visual tracking."
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