Marine scientists made contingency plans Friday for luring a pair of injured humpback whales that wandered up a river back to the Pacific Ocean.
For the second straight day, a marine mammal rescue crew aboard
a Coast Guard cutter planned to play 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.
But since the team's first attempt to direct the whales back to sea using the whale recordings did not work on Thursday, its members started preparing for Plan B - herding the animals down river with a gauntlet of 50 boats that would provide a less-pleasing soundtrack by banging on pipes underwater.
Those measures would be applied starting on Tuesday only if the more numerous and varied whale sounds the scientists intended to use on Friday do not do the trick or if the twosome do not start swimming toward the sea on their own over the weekend, said Frances Gulland, director of veterinary science at the Sausalito-based Marine Mammal Center.
"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."
On Thursday, the whales twice began moving out of the port after the sounds were broadcast from the smaller boat. But both times they turned back into the large basin that oceangoing freighters use for turning around.
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. A similar strategy of employing recorded whale sounds worked in 1985 with a humpback nicknamed Humphrey, which swam in the delta for nearly a month before returning to the Pacific.
But the situation near Sacramento was more complicated, they said. It involves a mother and calf, rather than a single whale, and the mother's concern for her baby may explain why she did not respond to the scientists' efforts to appeal to her stomach, Gulland said.
The pair also are much farther into the Sacramento-San Joaquin Delta than Humphrey was. The injuries add another dimension, as scientists say they do not know how the wounds might affect the whales' behavior. The larger whale had a gash 2 feet long and 6 inches deep, filled with blubber. The calf's wound was difficult to assess because it is on the animal's underside, below the water line.
"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."
The failure of Thursday's attempt also may 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.
(Copyright 2007 by The Associated Press. All Rights Reserved.)