RIO VISTA, Calif. (AP) _ Two wounded, lost whales circled near a Sacramento River bridge as boat crews banged metal pipes to try to herd them toward the open waters of the Pacific Ocean.
The whales, lost since more than a week ago, spent a second day Tuesday circling near the bridge about 70 miles from the Pacific. Both whales were apparently wounded during a run-in with a boat's propeller.
``The wounds appear to have worsened over time and their skin has changed from smooth and shiny to irregular and pitted,'' said Frances Guiland of the Marine Mammal Center.
Fresh water from the Sacramento River could hamper the whales' recovery, biologists said. Skin samples taken from the mother whale on Monday were sent to out-of-state labs to assess her general health and help identify her population stock.
Some crews in the more than two dozen boats blocking the humpbacks' path up the river tried herding the mother and her calf downstream by banging metal pipes beneath the water.
They hope to encourage the pair to return to salt water quickly, without upsetting the whales.
``Stressing even a healthy whale is not good. Stressing an injured whale is worse,'' said Brian Gorman, a spokesman for the National Oceanic and Atmospheric Administration.
The humpbacks, nicknamed Delta and Dawn, had traveled 90 miles inland more than a week ago before turning around at the Port of Sacramento on Sunday and heading back toward the ocean. They were making progress Monday until they reached the Rio Vista Bridge and began swimming in circles.
Scientists theorized the whales began circling because vibrations from traffic on the bridge upset them.