RIO VISTA, Calif. &

Encouraged by the response of two injured, wayward whales to the spray of a fire hose, marine scientists plan to use more hoses when they resume efforts next week to herd the pair back out to the Pacific Ocean.




The mother whale and her calf swam away when scientists aboard a fire boat on the Sacramento River sprayed a powerful hose in their direction on Friday morning, said Petty Officer Allyson Conroy, the U.S. Coast Guard spokeswoman.




"It seemed to work," Conroy said. "They moved away from the hoses."




Only one fire boat was used Friday, and the whales were able to swim around the vessel and the hose, Conroy said. Rescuers plan to bring out more boats and hoses on Tuesday and attempt to drive the pair back to the Pacific.




The two whales apparently took a wrong turn when they entered San Francisco Bay and traveled 90 miles inland up the Sacramento River. They turned around at the Port of Sacramento and were making progress Monday when they reached the Rio Vista Bridge and began swimming in circles.




The rescuers decided to try the fire hose after the lost whales resisted attempts to move them downriver with banging pipes, a flotilla of boats, and the recordings of killer orcas and fellow humpbacks. Scientists plan to give the whales a break over the Memorial Day weekend, when the river is expected to be crowded with holiday boaters.




The hose technique had never been tried before, and scientists did not know whether it would repel or attract the whales by making pressure streams and air bubbles in the water.




Scientists continue to be concerned about the whales' health. The mother and calf have deep cuts &

apparently sustained during a collision with a boat's propeller &

and the wounds are not healing in the fresh water.




The rescuers are working on a plan to inject the whales with antibiotics to protect them from infection. Scientists are still developing the drug and will likely use a dartgun or syringe attached to a pole to administer it.




Crowds of whale watchers were expected gather along the riverbanks to catch a glimpse of the humpbacks over the three-day weekend. Authorities planned to maintain a 500-yard buffer zone around the whales to keep boats away. They asked boaters to slow down when they pass through the area where the mother and calf are swimming.




State wildlife officials said the public was welcome to try to see the whales but warned against citizen attempts to move the animals.




"We ask that nobody try to engage in any operations of their own," Hurner said. "We're very concerned about the public's safety and the whales' safety over the weekend."