Whale update. Will piped-in sounds lure wounded pair back to sea?
By Carrie Peyton Dahlberg and Deb Kollars - Bee Staff Writers
Last Updated 6:49 am PDT Thursday, May 17, 2007
This morning, a team of scientists and animal rescuers will find out whether the familiar sounds of humpbacks feeding will tempt a pair of lost whales back to their ocean home.
The two whales, a mother and calf, turned up in the Port of Sacramento's Lake Washington on Wednesday after an ill-fated journey from the San Francisco Bay, up the Sacramento River and into the Deep Water Ship Channel in West Sacramento.
The port waters marked a dead end for the whales. Long-term, they cannot survive in fresh water, and so far have been unwilling or unable to turn around and find their way back to the sea.
On Wednesday, they went under a very public microscope, as scientists in boats drew close to take photographs of their condition, while crowds gathered on nearby levees to catch glimpses of the large, graceful creatures. By the end of the day, thousands had come for a look.
The crowds were a worry to wildlife experts, who feared they would distress the animals, and to officials concerned about potential levee damage. City officials urged people to refrain from gathering on the levees, but said they would not stop anyone from coming for a look.
At daybreak Thursday, a crew was in the channel testing the sounds of humpbacks eating and other acoustic luring efforts to get the mammals back to sea, said Jim Milbury of the National Marine Fisheries Service.
Wednesday's inspections by scientists revealed both whales are wounded, but the mother whale is not entangled in fishing debris, as previously believed.
Pictures taken from an Alaska Whale Foundation boat showed close-up views of barnacles on the calf's face and a long, pale gouge along the mother's back.
The gash likely came three days ago from a boat's propeller in the Sacramento River, said Frances Gulland, director of veterinary science at the Marine Mammal Center.
The wound has a large flap of skin. The flap's movements back and forth had led some to initially believe the animal was entangled in rope or other gear.
The calf has a deeper, potentially more troubling wound, Gulland said. The same boat could have wounded both animals, its propeller slashing the mother's back as she tried to surface and the youngster's underside as it rolled or swam on its side. The boat's operator was likely aware of the collision, Gulland said.
The smaller animal's wound is harder to assess because it is visible only when the whale rises far out of the water. The mother's wound, 2 feet long and 6 inches deep, penetrated only the blubber, not muscle.
Pictures of the injuries were shown to about two dozen wildlife and public safety officials gathered at UC Davis Wednesday for a two-hour strategy session on how to help the animals return to their saltwater home in the Pacific. The session drew representatives from the California Department of Fish and Game, the National Marine Fisheries Service, the U.S. Coast Guard, the Port of Sacramento, West Sacramento police, the Marine Mammal Center and the Alaska Whale Foundation.
Among those attending was Laurie Gage, a veterinarian who helped Humphrey the humpback whale return to the San Francisco Bay in 1985 after it became stranded in the Sacramento River near Rio Vista.
Gage told the group very few humpbacks have wound up in such inland waters. The Humphrey experience, she said, offered the best model for helping the currently stranded whales.
In the case of Humphrey, scientists tried numerous strategies over 26 days to help the wayward whale return to the Pacific, with little success.
Finally, the scientists began playing underwater recordings of humpbacks feeding.
"It was either coincidence or it worked like a charm," Gage said. "Because that was when he went out."
This morning, rescuers plan to play underwater sounds of humpbacks feeding downstream of the whales. They may use boats to do some herding.
Scientists hope to attach a suction cup tagging device to at least one of the whales. It won't stay on forever, but veterinarians don't want to risk injury by using embedded tracking tags.
If the luring effort succeeds, scientists estimated, it would take about six hours for the animals to swim out of the channel and into the Sacramento River.
Shipping and small boat traffic were halted on the channel. Recreational boaters were asked to stay at least 100 yards away.
Excerpt from:
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