Wayward whales heading home

A mother-and-child pair of wounded humpback whales stranded in the Sacramento River Delta were headed toward the ocean late Sunday after roaming for a week in brackish inland waterways.

U.S. Coast Guard officials said the whales were swimming southwest in a deep water channel about 20 miles southwest of the Port of Sacramento by 9 p.m.

Coast Guard officials said the humpbacks appeared to right their course on their own.

Rescuers had tried for days to direct the whales to the ocean using loud pipe-banging noises to nudge them from behind and recordings of humpback sounds to lure them southward to the sea.

But those efforts were suspended for the weekend.

Scientists observing the whales last week spotted a 2-foot gash across the back of the 45-foot-long mother whale. The 20-foot-long calf appeared to have a more serious gash across its body. The cuts were apparently from a boat or ship propeller.

As darkness fell Sunday, the Coast Guard escort that had followed the whales all day ceased trailing the duo so the vessels would not accidentally hit them.

Still, several obstacles remained in the whales’ path back to sea, including bridge pylons and sloughs leading to muddy deltas.

Nine boats carrying Coast Guard and wildlife officials followed the whales to prevent them from turning around.

The pair had traveled nearly 100 miles up the river delta, drawing crowds of spectators. At one point, hundreds had gathered at a dirt levee south of downtown Sacramento to glimpse the lost leviathans.

Scientists do not know why whales occasionally veer off course into alien waterways.

A humpback was lost in the delta for 26 days in 1985. Nicknamed Humphrey, the whale’s tribulations were closely followed until it returned to San Francisco Bay. Afterward, a children’s book was written about the adventure.

Scientists are divided over whether humans should assist lost whales. Some believe helping them return to their natural habitat interferes with natural selection.

peter.hong@latimes.com

The Associated Press contributed to this report.