A juvenile humpback whale entangled in hundreds of feet (meters) of heavy rope off the Hawaii coast was being tracked by marine experts Wednesday.

"The entanglement is life-threatening," said Ed Lyman, marine mammal response manager for the Hawaiian Islands Humpback Whale National Marine Sanctuary. "It's in the mouth, and it's over the body. It's yellow, polypropylene line, pretty heavy gauge, and it's several hundred feet of line on the animal."

A location transmitter was attached to the rope Tuesday after earlier rescue efforts failed because of rough water in the channel between Maui and Molokai, Lyman said.

"If the whale stays nearby and the weather cooperates, we can mount another effort," he said.

Lyman estimated the whale was tangled in 400 to 500 feet (120 to 150 meters) of rope that trailed in two long knotted strands. He estimated the whale is between 2 and 5 years old, and about 30 to 35 feet (9 to 10 1/2 meters) long.

The effort to save the whale began Tuesday after a Pacific Whale Foundation tour boat spotted the mammal about 3 miles (5 kilometers) off Maui. A U.S. Coast Guard helicopter also helped monitor the whale, he said.

The marine sanctuary, which was created by Congress in 1992 to protect humpback whales and their habitat in Hawaii, lies within the shallow warm waters surrounding the main Hawaiian Islands.