SACRAMENTO, Calif. – With two wandering humpback whales refusing Wednesday to budge past a bustling steel bridge across the Sacramento River, rescuers announced plans to escalate their tactics today to prod the wounded leviathans back to the sea.
Rescuers say they will start out today playing the sounds of humpbacks feeding in hopes of luring the whales, both bearing injuries likely inflicted by a ship’s propeller, toward saltier water where their wounds could better heal.
If those recordings don’t coax the humpbacks to pass beneath the bridge, the flotilla may play the sounds of killer whales feeding on California gray whales. They also intend to try a variety of man-made shrieks from a synthesizer.
The risk, authorities acknowledged, is that hostile sounds might put the whales under even more stress, causing their already deteriorating health to worsen.
But frustrated rescuers from the U.S. Coast Guard, National Marine Fisheries Service and California Department of Fish and Game seemed resigned to an escalation.
“We’ve been trying to do this in a very measured, gradual approach,” said Trevor Spradlin, a National Marine Fisheries Service wildlife biologist. “But we don’t seem to be making as much progress as we hoped.”
A flotilla of 19 boats banging steel pipes Wednesday morning failed to herd the mother and calf past the Rio Vista Bridge.
Spradlin said it remains unclear how much longer the whales can survive out of their natural saltwater environment. But their normally slick skin has grown pitted and their wounds are failing to heal properly while they lurk in the fresh water of the Sacramento River and delta.
The pair continued Wednesday to exhibit the tail slapping that started Tuesday. Although biologists commonly consider such action a sign of stress, “it could be the mother is simply communicating with her calf,” Cordaro said.