A plane, helicopter and boat searched Saturday for a blue whale entangled in fishing line off southern California after rescue efforts were suspended overnight, an official said.

The blue whale was tethered to a red-orange buoy Friday that should allow rescuers and the seafaring public to more easily spot it, said Peter Wallerstein, president of Marine Animal Rescue, a nonprofit authorized to rescue marine animals.

"It's really big," Wallerstein said of the animal.

The entangled whale is 80 feet long, he said. The longest blue whale ever measured was more than 108 feet long, the Smithsonian Institute says.

As gargantuan as it is, however, the leviathan proved elusive as of early Saturday afternoon, and crews continued their search, Wallerstein said.

The blue whale, an endangered species that's also Earth's largest animal, was last seen Friday 4 miles off the southern end of Catalina, an island 22 miles off mainland California, Wallerstein said.

The effort marks the first time that a blue whale would be rescued off California, the nonprofit leader said. Federal and local teams are working together on the case.

"They can move pretty quick," Wallerstein said of the blue whale's whereabouts. "They travel long distances in a short period of time."

If anyone spots the whale, he or she should call authorities. "One swish of the tail can kill you or knock your boat out of commission," Wallerstein said.

Aerial photos Friday showed the whale surfacing and then diving, pulling a long fishing line.

"It's in pretty good condition," Wallerstein said Saturday. "It looks a little thin. It's swimming really good. We put a buoy on it last night that should slow it down, and we should be able to spot it."

The searchers' mission is to free the blue whale from the fishing line. Whale watchers first reported the whale trapped in the netting.

The National Marine Fisheries Service has made a national priority out of addressing the injury and mortality of large whales entangled in fishing gear such as traps, pots and netting.

An average of 11 large whales have become entangled annually in such gear on the West Coast from 2000 to 2012, the National Oceanic and Atmospheric Administration says.

"However, along the U.S. west coast, much is unknown about why, when, where, and how whales are seriously injured or killed due to entanglement, how this threat may be affecting their populations, and what can be done to minimize the risk," said a 2013 report by NOAA's National Marine Fisheries Service.

There are 10,000 to 25,000 blue whales in the world, according to the World Wildlife Fund. They can be found off California, Chile and the Coral Triangle near Indonesia.

CNN's Michael Martinez reported and wrote from Los Angeles, and Ralph Ellis and Sheena Jones contributed from Atlanta.