Wednesday, May 07, 2008

Stopping Ship-Whale Collisions

Continued from page 1

By Anna Davison

Whale detection: Ten whale detection buoys are spaced five miles apart in Massachusetts Bay. The system, which cost $1.3 million up front and will cost about $25 million to operate over the coming decades, was funded by a company that built a liquefied natural gas import facility in the bay, where endangered North Atlantic right whales congregate in the spring. Credit: Woods Hole Oceanographic Institution

The detection buoys are positioned five miles apart so that "when a whale calls in the area, it's picked up by more than one buoy," says Peters. "There are no dead spots." Suspended 50 feet below each buoy is a hydrophone, which is linked to the floating buoy by a reinforced rubber hose, designed to reduce extraneous noise from the mooring. This "gumby hose," as the developers call it, can stretch to more than 100 feet, keeping the hydrophone steady in rough waters.

Cables embedded in the gumby hosetransmit sound signals from the hydrophone to a surface buoy containing a processor and software that analyzes underwater noise. Sounds are rated on a scale of 1 to 10, according to how likely they are to be right-whale "upcalls," which the animals use to keep tabs on each other.

"A right whale has a real hard time keeping its mouth shut," Clark says. "They call to say, 'Is there anybody out there? Is there food over there? Do you want to get together? What's going on?'"

Sounds that are likely to be right-whale calls--rated at least 6 out of 10--are sent via satellite to Cornell to be checked by research assistants. Packages of two-second audio files are sent every 20 minutes, so during the busiest season, when whales and calves congregate in the Northeast, thousands of clips come in every day.

When LNG tankers are in the Boston area, Cornell's whale listening team works around the clock. Otherwise, the clips are checked twice a day. Clark admits that he has developed an addiction. "They call me the 'clip-checking fairy,'" he says. "I can't help myself."

Soon LNG tankers will automatically receive warnings from whale detection buoys, but until that part of the system is up and running, "I'm calling the captain of the ship and saying, 'You've got whale,'" Clark says. The information is also distributed via fax and e-mail as part of the Right Whale Sighting Advisory System, which also includes sightings gleaned from aerial surveys. Information from the buoys is also available on a public website.