Scientists hope sounds push, pull whales to sea

WEST SACRAMENTO, Calif. – Two lost humpback whales continued their odyssey up a busy delta river channel Wednesday as hundreds of onlookers watched with a mix of amusement and concern.

The mother and calf, they learned Wednesday, apparently suffered wounds inflicted by a boat propeller. In a packed news conference, scientists said the injuries came after the pair entered the Sacramento River Delta on Sunday and do not explain why the whales veered off course into inland waters.

Rescue workers also announced an ambitious plan beginning today to coax the rare whales back toward the open ocean. The strategy will use a series of underwater sounds – pipe-banging noises prodding the whales from behind, with recordings of feeding humpbacks played in front to lure them southward.

That plan worked in 1985 when rescuers saved an errant humpback whale named Humphrey, ending the creature’s much-publicized 26-day wanderings up and down the delta.

“We want to get these two whales back to San Francisco Bay so they can exit beneath the Golden Gate Bridge back to the ocean,” said Frances Gulland, a marine mammal veterinarian with the Sausalito-based Marine Mammal Center, which is assisting federal officials in the rescue.

Experts believe there are fewer than 6,000 humpback whales in existence. The mammals, which can exceed 50 feet in length and weigh 50 tons, are protected under both the U.S. Endangered Species and Marine Mammal Protection acts.

Humpback whales traditionally migrate twice a year between feeding grounds in colder waters off Washington state, Oregon, Alaska and Canada and the warmer breeding waters off Central America, Hawaii and Mexico. The mother and calf were apparently headed north when their navigation went amiss.

In four days, they swam 90 miles up the Sacramento River from San Pablo Bay. On Wednesday they were spotted in a deep-water channel used by ocean-going ships that dead-ends at the Port of Sacramento.

Gulland said the 45-foot-long mother whale, which weighs about 45 tons, suffered a two-foot-long gash across her back that was not life threatening. She said what had at first been mistaken as a fishing line dangling from the whale was a flap of skin hanging from the six-inch-deep gouge. The calf, however, had a perhaps more serious wound beneath its right flank.

Gulland said there was no need to treat the creatures right away and that the mother’s wound would likely heal in cleansing ocean waters. She said there was no way to determine yet the long-term health of the calf, which she said was about 20 feet in length.