The 30-foot whale that washed up at Point Reyes National Seashore last month had wounds that indicated it got tangled in something in the ocean before its death, researchers said Friday.

The Sausalito-based Marine Mammal Center, which handled the necropsy of the juvenile humpback whale after it washed ashore Christmas Eve, said its team found indented marks and roughed-up skin on the corners of the whale’s mouth, around the back of its neck and in circles on its shoulder blade. Bloody tissue was found around the animal’s neck and head.

Researchers concluded the evidence pointed to a previous entanglement, but they aren’t sure exactly what in the sea snagged the whale.

“The entanglement wasn’t actually physically on the animal, and due to decomposition and bloat, you can’t make that decision,” said Barbie Halaska, research assistant with the mammal center.

Fishing gear is one possible cause of entanglement, but it could have been “any number of things” given the amount and variety of debris and trash in the waters, Halaska said.

The mammal center said its team can’t say with certainty that the entanglement led directly to the whale’s death. The official cause is “undetermined.”

California’s Dungeness crab fishery has seen an escalating number of whale entanglements in gear, encounters that often prove deadly for the marine mammals. New regulations have been approved to pressure crabbers to ensure they retrieve lost traps, buoys and lines.