State officials and marine biologists were on the lookout today for a wayward, 35-foot whale that put on a show yesterday near the Chesapeake Bay Bridge.
The species has not been determined, but authorities think the whale may be a humpback, which can grow to about 50 feet in length and weigh up to 50 tons.
The apparently healthy whale was last seen at dusk yesterday about a mile south of Kent Island. Barbara MacLeod, a spokeswoman for the state Department of Natural Resources, said there had been no sightings by about midday.
Officials at the Virginia Marine Science Museum in Virginia Beach, Va., have been monitoring at least eight humpbacks since December. The animals have appeared for the third straight year off the Virginia Beach shoreline and at the mouth of Chesapeake Bay.
"There's been a lot of whale activity along the East Coast lately," said Mark Swingle, an assistant curator at the Virginia museum. He has been in contact with Dr. Cindy Driscoll, a DNR veterinarian, discussing whether one of the Virginia whales may have come north in search of food.
The whales off Virginia appear to be young animals, not yet of breeding age, that are given to wandering, Mr. Swingle said.
Watermen and pleasure boaters gathered and watched until dark yesterday as the jet black whale swam in waters ranging from 40 to 60 feet deep near the bridge. Meanwhile, the Coast Guard and state Natural Resources Police were advising boaters by radio to stay clear.
"It was really beautiful," said Eddie Cantler, a 31-year-old waterman from St. Margarets.
"People need to keep their distance from it," said Dr. Driscoll, who also is the state coordinator for a marine mammal and sea turtle stranding network. "A large whale like that can be a real hazard to small boats -- unintentionally," she said.
Dr. Driscoll added that federal law protecting all marine mammals dictates that boaters not get near the animals. Harassment of whales can bring fines of up to $10,000, she said.
The whale apparently was first spotted about 10 a.m. yesterday near the mouth of the Potomac River. It was feeding and appeared to be in good health, observers said. Marine biologists stood by in case it appeared to need assistance.
David Schofield, a marine mammalogist at the National Aquarium in Baltimore, said large whales usually stay in the ocean but sometimes stray closer to shore while following a school of fish.
Mr. Schofield, who also is the marine mammal stranding coordinator for the Aquarium, said single large whales, because they need to eat so much, are known to range great distances in search of food.
"They are opportunistic feeders," he said. "If the food is plentiful, they will head to that area."
"Most of the other occurrences of large whales [in the bay] in the past 15 years have been dead animals caught on the bows of freighters," said James Mead, curator of marine mammals at the Smithsonian Institution in Washington.
Dr. Driscoll said the last whale sighted in the Maryland portion of the Chesapeake was near Rock Hall in late September. That whale, also thought to be a humpback, eventually worked its way down to the lower bay and disappeared, she said.
Scientists believe several thousand humpbacks ply the western Atlantic, ranging from Guyana and the West Indies to Bermuda in winter and from New England and Newfoundland to the Arctic Ocean in summer. The species occurs worldwide. Its numbers were greatly reduced by hunting, since humpbacks yield the most oil for their size.
In colder waters of the North Atlantic, humpbacks feast on herring, capelin and other fish, Mr. Schofield said. "What they would be eating in the bay, I don't know," he said.
Humpbacks and other large whales can consume more than a ton of fish per day, according to the American Cetacean Society, which studies whales, dolphins and related marine mammals.
Anyone who sees the whale or any other marine mammal can call a marine mammal hot line at 1-800-628-9944. The information will help scientists assist an injured or trapped animal and help in the gathering of biological data.