Big whale, big sharks, big stink: R/V Tioga sent into action to perform whale necropsy at sea.

A tanker first spotted the whale on Sept. 9 about 24 miles southeast of Nantucket, Mass. It floated belly up--species unknown, cause of death a mystery.

Michael Moore, a biologist at Woods Hole Oceanographic Institution, scrambled into action. He gathered several sharp flensing knives, like those once used by whalers, to perform a messy but necessary partial necropsy to learn more about the whale. Then he and a team from the Cape Cod Stranding Network and the National Oceanic and Atmospheric Administration set out on Sept. 11 aboard WHOI's rapid-response coastal research vessel Tioga.

After two hours of searching for the carcass, help came from above: A pilot radioed the whale's location to Tioga.

"The pilot said, 'Look, I want you to know that there are at least 200 sharks down there,' "Moore said. "He told me there were more sharks than he'd ever seen in one place in 25 years of working at sea."

Moore has conducted more than 35 whale necropsies, usually on whales washed ashore. In necropsies at sea, he typically works alongside the whale in a small rubber boat deployed from larger vessels. But not on this day, with sharks in the water. Ken Houtler, Tioga's captain, maneuvered the vessel alongside the whale. Moore and others tied a line around the whale's flipper and tail and cinched it to the boat's side. Floating parallel to Tioga, the whale stretched as long as the 18-meter (60-foot) vessel (see back cover).

Like a human autopsy, the necropsy would provide clues to why the whale, a young female finback, died. It may have been struck by a ship or become entangled in fishing gear. Moore also searched for evidence that toxic algae from a record bloom in New England coastal waters this spring may have played a role.

Gas buildup from decomposition had caused the animal to bob like an overinflated raft. To relieve the gas pressure, Moore made a series of deep, foot-long cuts--called deflationary stabs--using a knife attached to a long wooden pole. This slowly released the gas, causing the whale to flatten yet remain buoyant.

Leaning over the side of the vessel, Moore worked from bow to stern, making a 30-foot-long incision in the whale. It now resembled a dugout canoe, and Moore donned a wetsuit and rubber booties, secured a harness and safety line attached to the boat, and climbed into the whale's long incision.

Several sharks lingered nearby, feeding on the whale under the surface. Some appeared with streaks of red paint on their noses and backs after brushing against Tioga's cherry-colored hull.

For the next hour, Moore took skin and blubber samples for subsequent analysis. As soon as he finished the necropsy, Tioga fled quickly. The research team's concern about the sharks had been overwhelmed by the stench of decaying whale, an odor Houtler called "straight out of a horror movie."

"Maybe some people will have nightmares about the sharks we saw," he said. "Any bad dreams I have will come from that smell."

Amy E. Nevala This project was supported by NOAA's National Marine Fisheries Service, with assistance from the Cape Cod Stranding Network.