Dave Anderson told the Orange County Register he had spotted the whale, nicknamed Lily just outside the harbor entrance around noon.
"She's really not looking good today," said Anderson, who described the 30-foot California gray whale as "kind of moving back and forth."
Lily has been hanging around Dana Point for about a week to both the delight and distress of onlookers, who fear the whale is sick.
"Everything this whale is doing leads to the same conclusion: Either the whale is really old or it's not healthy," Rick Baker, vice president of education at the Ocean Institute, told the Los Angeles Times.
Anderson and other volunteer members of the Orange County Large Whale Disentanglement Team cut an estimated 150 pounds of fishing nets and ropes from Lily on Wednesday hoping it would free it up enough to return to open sea and continue its migration from Mexico to Alaska.