The carcass of a dead humpback whale that was brought into the Port of Valdez on the bulbous bow of an oil tanker has been towed out to sea.

The tanker crew contracted a fishing vessel to drag the whale out of port Wednesday. The charter's captain, Bernie Culbertson, told the Valdez Star he plans to let go of the carcass about 70 miles south of Valdez.

No one noticed the humpback stuck on the bow of an Exxon oil tanker until the ship was preparing to dock Monday afternoon in Valdez, according to spokespeople for the company and for the terminal.

It's not clear -- and may never be known for certain -- whether the whale was already dead when the tanker Kodiak struck it, and when and where that occurred, authorities say.

Logistical difficulties mean no necropsy will be performed, though the National Oceanic and Atmospheric Administration Fisheries Service is investigating the incident.

"There's been no factual evidence brought forth that associates the vessel with the demise of the whale," said Ray Botto, external affairs manager for SeaRiver Maritime Inc., a company owned by Exxon Mobil that provides shipping services for the oil giant.

Nobody felt or saw anything out of the ordinary; for instance, no change in water patterns, Botto said. After docking at the Valdez tanker port, the Kodiak took on oil and left Tuesday afternoon, just a few hours behind schedule.

The ship wasn't damaged, he said.

The Kodiak, a double-hulled vessel built in 1978, is a huge ship, measured at 122,805 deadweight tons, according to U.S. Coast Guard Petty Officer Sara Francis.

"It's unlikely that a 40- to 50-foot whale would cause any significant damage," Francis said. And no one reported any, she said.

Humpbacks are listed as endangered, but new research indicates their numbers are recovering. There are an estimated 20,000 humpbacks in the North Pacific Ocean and many migrate to rich feeding grounds around Alaska each summer, said John Calambokidis, a research biologist and authority on humpbacks based in Olympia, Wash. He was one of the leaders in a major humpback study published last year. The humpback population has been growing 5 to 7 percent a year, he said.

No one remembers another incident like this ever occurring at the Valdez tanker port, which has seen 20,000 tanker calls, said Michelle Egan, corporate communications director for Alyeska Pipeline Service Co., which runs the terminal.

It's been the talk of the terminal this week, she said. "It's just a very odd occurrence," Egan said. "They've been really sort of intrigued by it and responding to it."

It's relatively rare for a ship to collide with a whale in the waters around Alaska, but it happens every couple of years or so, said Sheela McLean, a NOAA Fisheries spokeswoman.

Monday afternoon, the tanker Kodiak was escorted into the port by tugboats, a standard practice.

"At no time, did any of the crew of the vessel or the tugboats, who were in close proximity to the bow during the maneuvers, did anybody sight the whale," Botto said.

It wasn't until the tanker was approaching the dock that a crew member on a separate boat who hands the line from the ship to the dock spotted the humpback on the bow, Botto said.

Questions about "how the whale got there, how long it had been there, what condition it was in, how long it had been in that condition, how did it get in that condition, are all things I don't have any information that I can relay to you," he said.

The Coast Guard, Alyeska, the state Department of Environmental Conservation, and NOAA Fisheries were all alerted about the whale, he said. The terminal advised the crew to go ahead and dock, Egan said.

Once people were able to get a good look at the whale, they realized it was dead, she said.

During the process of tying up the Kodiak, the whale floated free, so crews decided to secure it to a buoy temporarily to prevent it from creating a hazard, Egan said.

Scott Adams, a NOAA Fisheries enforcement officer, is investigating the whale's death.

He's trying to determine what caused it and whether anything could have been done differently to prevent it or minimize the chance of a repeat occurrence -- whether shipping lanes needed to be altered, for instance.

It would have been helpful if a necropsy could have been done, but a team couldn't be assembled quickly enough, and the whale was decomposing, he said. People were reporting the stench was strong by Tuesday, Egan said.

"Without the necropsy, a significant component is lost," Adams said. "But there's still stuff to be done and there's still stuff to be learned. And I may be able to come up with some reasonable conclusion by the end of it."

The investigation could wrap up in about a week, he said.

On Wednesday, a fishing vessel contracted for the job by SeaRiver was towing the dead whale out of Prince William Sound to a remote spot. Authorities say it should drift away and decompose.

The Associated Press contributed to this report.

Find Lisa Demer online at adn.com/contact/ldemer or call 257-4390.

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