WEST SACRAMENTO, Calif. -- Hundreds of people lining the shoreline around the Port of Sacramento Sunday for the most popular show in town -- watching two wayward humpback whales circle the port -- had a nice surprise on Sunday afternoon.

The whales began following two tugboats that are headed out of the port and toward the Pacific Ocean. As of Sunday afternoon, the whales had moved about five miles closer to the ocean.

The California Highway Patrol urged people to stay away from the area where the whales had been circling, but for a sixth day in a row, thousands showed up. About 10,000 people have turned out thus far to watch the whales, officials said.

The CHP recommended if people do drive to Sacramento, they should bring water and a lot of patience due to the big crowds.

Scientists have been planning to resume efforts Tuesday to lure the pair back to the Pacific Ocean by using dozens of boats and noises of pipes banging underwater to corral the whales back toward the ocean.

Lt. Gov. John Garamendi said Friday at a news conference he was naming the whales Delta and Dawn, after the Helen Reddy song.

Garamendi said the name Delta came from the body of water the whales are lost in and Dawn because it brings in a new day.

On Friday, for the second straight day, a marine mammal rescue crew aboard a Coast Guard cutter played recorded sounds of other humpbacks feeding to the mother whale and calf stranded at the Port of Sacramento, where the two hit a dead-end after traveling 90 miles through San Francisco Bay and up the Sacramento River.

The whales were not responding to the sounds, but a similar recording procedure worked in 1985 with a humpback nicknamed Humphrey, which swam in the delta for nearly a month before returning to the Pacific.

However, biologists said the situation facing them near Sacramento is more complicated. It involves a mother and calf, rather than a single whale, that are much farther into the delta than Humphrey was. The injuries add another dimension, as scientists say they do not know how the wounds might affect the whales' behavior.

"It's brand-new territory. It's not like we're applying something we have a lot of experience with in the past. It's essentially an experiment," said Pieter Folkens, a biologist with the Alaska Whale Foundation who was part of the rescue effort. "We really can't have high expectations of a positive outcome. We're certainly doing our best."

Meanwhile, the rescue efforts are taking place inside a very industrial port, where business operations continue.

"The current vessel in port now is the Jin Quan, unloading 31,000 tons of bulk cement. They're scheduled to complete operations on Tuesday at which time they'd like to depart," Mike Luken with the Port of Sacramento said.

There is another ship scheduled to come in that same day, which gives all the more reason why rescuers are hoping their sound experiments will be successful.

"We want to be as careful and as cautionary as possible because we really do not want to stress the mother or calf in any way because they are compromised by the injuries."

Biologists hope to get the whales back into the ocean, where food is more plentiful and the salt water can heal their cuts, apparently inflicted by a boat propeller when the mammals were in the river.

The failure of attempts to use whale sounds could be related to the recordings used. They were of Alaskan whales that might be part of a different pod than the one the mother and calf belong to.

"This is a humpback probably from a different population, probably the Mexico-California population," Folkens said. "So it's kind of like speaking Chinese to somebody from Boston, but at least you recognize that it might be another member of the same species."

The good news on Friday was that biologists did not detect any significant changes in their health from a day earlier, Gulland said.

"Both mother and calf are still swimming and breathing and surfacing at similar rates as they were over the past few days," she said.

Even if the recordings eventually work, scientists said it could take anywhere from several days to several weeks to lure the whales back to the bay.