A crew from the Pacific Marine Mammal Center in Laguna Beach works to untangle a gray whale from a line off the coast of Orange County on Tuesday. (PACIFIC MARINE MAMMAL CENTER / April 19, 2012)

The Pacific Marine Mammal Center, U.S. Coast Guard, the Ocean Institute and others are still actively searching for an entangled gray whale that was first spotted Tuesday.

The whale was first reported off the shore of Newport Beach. It continually drifted south, and the PMMC crew caught up with it that afternoon off the coast of San Clemente.

PMMC Director of Development Melissa Sciacca said the center's crew left the whale about 6:30 p.m. Tuesday near San Onofre, after spending several hours trying to free it. They had to return to shore when darkness fell.

The gray whale, which has been nicknamed June, is about 40 feet long and was towing a 50- to 100-foot line on its left pectoral fin. There was also line caught near its mouth, Sciacca said.

Due to the location of the debris, the operation was extremely dangerous for the crew, which consisted of Dean Gomersall, Scott Sedlick and Dana Friedman.

The crew was able to successfully attach buoys to the debris, which allowed the line to float and made it easier to maintain a position on the animal.

They were able to cut away a good portion of the line Tuesday, Sciacca said, but there was still debris left.

As of Thursday afternoon, the rescue team still hadn't relocated June.

"The entanglement impeding June appeared to be a relatively new injury, and as far as we could tell, was not deeply embedded," lead rescuer Gomersall said in a statement. "This makes it possible for the debris and buoy attachments to have come off of the animal, attributing to a possible reason of why the whale has not yet been located. That is what we're hoping for. It's also possible that the whale has continued migrating west into deeper waters, or has turned north to finish its migration toward Alaska and is outside our search zone."

joanna.clay@latimes.com

Twitter: @joannaclay