Germans have been treated to the rare sight of a lone and wayward humpback whale swimming in the Baltic Sea, but marine biologists said it may be doomed because the waterway lacks the conditions such mammals need to survive.

The humpback has been spotted several times near Rostock city in recent days, according to the biologists, who say such whales don't typically range too far into the Baltic.

As the whale drew attention from newspapers and Web sites, Joerg Feddern, a biologist with the environmental group Greenpeace, worried that its presence in the Baltic is not normal.

He said the last time a humpback was seen there was back in 2004, and that the Baltic is not the best place for the mammal.

"There's not enough food for a humpback whale in the Baltic Sea," agreed Klaus Harder, a biologist at German Ocean Museum for Sea Mammals in Stralsund. "Worst case scenario: The whale could starve to death."

Though he's not seen the cetacean personally, Harder confirmed it is a humpback by comparing photos of the animal, dubbed "Bukie" by the German press, to the humpbacks he regularly worked with off the coast of Massachusetts when he lived in Boston.

The humpback is a type of baleen whale, distinguished by its long, narrow flippers and large knobs on its head, jaws and body. Humpbacks can reach up to 52 feet in length and some 40 tons in weight, and feed largely on krill, small fish and plankton.

As to why Bukie is in the Baltic, that's sparked debate of sorts.

One theory holds that the whale got confused and swam into the sea. Another posits that the mammal may have been directed by currents or could have simply been following a school of fish.

"The Baltic Sea is a connecting sea to the North Sea. Fish and the whale could have easily followed the current flowing into the Baltic Sea," said Feddern.

Another theory holds that the whale became confused because of ship traffic.

"It is also possible that the whale became confused because of underwater noises," Feddern said. "Ships are very loud underwater."

Unfortunately for Bukie, finding a way back out and into the North Sea and the Atlantic Ocean could be hard due to the narrow opening of the funnel-shaped Baltic Sea.

"There are no signs for the whale to follow," Feddern said.

He doubted that the whale could be led out of the sea. At most, the animal might have to be very carefully directed away from shallow water by navigating boats between it and the shore.

"This animal must find its own way out," he said.