West Sacramento, Calif. – Biologists tried Thursday to use recorded siren songs of humpback whales to lure an injured female and her wounded calf from a shipping channel and back toward the Pacific Ocean 90 miles away.
When the researchers played the underwater recordings from an 87-foot Coast Guard cutter, the whales swam away from the sound rather than toward it.
Hours later, the whales were still swimming at the Port of Sacramento, where they have been since Tuesday. Scientists then decided to move the sound equipment to a 25-foot Coast Guard vessel, believing the noise from the larger ship’s generator may have interfered.
The trick worked in 1985 with a humpback nicknamed Humphrey who wandered nearly a month in the Sacramento-San Joaquin Delta before heading to the ocean.
But biologists said the latest situation is more complicated: It involves a mother and a calf rather than a single whale, and the pair are much farther into the delta. The injuries add another dimension, as scientists say they do not know how the wounds might affect the whales’ behavior. The injuries were apparently caused by a boat propeller.
If the whales can be returned to their natural sea-water habitat, which is cleaner than the fresh water in the port and where food is more plentiful, they likely won’t need treatment, the researchers said.
If the sounds aren’t enough, wildlife officials will try a different tactic – lining the channel with more boats to herd the whales in the right direction.
