Wind and rough seas are impeding efforts to free a young humpback whale from a tangle of heavy rope wrapped around its mouth and body.

Data from a transmitter attached to the lines entangling the 35-foot yearling indicated it was swimming yesterday in waters northwest of Läna'i, said Ed Lyman, marine mammal response manager for the Hawaiian Islands Humpback Whale National Marine Sanctuary.

The whale is traveling with an adult female whale and an adult male, making efforts to cut the heavy-gauge propylene line especially tricky, he said.

Lyman said his team caught up with the animal late Wednesday afternoon off Launiupoko after its location was reported by a Pacific Whale Foundation vessel. By then, a good portion of the 400 to 500 feet of rope originally seen around the whale apparently had been pulled off when a first transmitter broke free, he said.

A second transmitter was attached Wednesday, but Lyman, who used a knife attached to a pole, was unable to remove the remaining rope.

"We lay the knife on its back and just missed cutting the line," he said.

"The yearling didn't respond; it stayed smooth but the mother did a little tail flick to give us a little warning maybe."

Lyman said he is rigging a longer, light pole to use when weather conditions permit further attempts to free the whale.

The entangled whale was first spotted Tuesday by a different Pacific Whale Foundation vessel.

Lyman speculated that the whale became tangled in the line while visiting its winter feeding grounds off Alaska. The animal has abrasions and a partially healed wound behind its blow hole, probably caused by the rubbing of a knot in the rope.

Despite the injuries, "this guy right now looks in pretty good health" and should fare well once the line is removed, Lyman said.

An average of six to eight confirmed whale entanglements are reported in Hawai'i each season, he said.