Two Wai'anae fishermen reported spotting a humpback whale about a mile off 'Ohikilolo yesterday, but officials can't figure out whether it could be the first of the season, the last of last season, or perhaps a case of mistaken identity.

"It was a single adult humpback, traveling southward and moving real slow," said Tori Cullins, director of the Wild Dolphin Foundation in Wai'anae. She and her husband, Armin Cullins, took reports from two fishermen who reported seeing the lone animal off the Wai'anae Coast. One reported seeing it breaching, Armin Cullins said.

It is very unusual for a humpback to be in Hawaiian waters at this time of year. The breeding and calving season generally runs from November to May, although the first sightings have been as early as mid-September. The whales do not eat while here. They feed during the summer months in the rich, cold waters farther north, said Jeff Walters, co-manager of the Hawaiian Islands Humpback Whale National Marine Sanctuary.

"This animal must be starving. I don't know what it's eating," he said. Walters added that if the sightings are accurate, it is more likely to be a late-stayer from the 2004-2005 season than the first of the 2005-2006 season.

"I would suspect that it's a straggler that hasn't left yet. Some mothers will stay around as late as possible to give their calves the best chance possible. I have heard of a mother and calf that were in South Maui and Ma'alaea as late as July a few years ago," he said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.