KA'ANAPALI, Maui — Sunset cocktail cruises off Ka'anapali yesterday turned unexpectedly into the first whale-watching trips of the season when Maui's most-anticipated visitor made a surprise appearance.

A single juvenile humpback whale was spotted by several tour boats a couple of miles offshore, the first reported whale sighting in Hawai'i after the summer feeding period in colder arctic waters.

The whale was first spotted around 4:30 p.m. by the Hyatt Regency's Kiele V. Passengers and crew aboard the Pacific Whale Foundation's Manutea observed the marine mammal less than an hour later. "We saw it surface a couple of times, and we saw a couple of flukes and a couple of peduncles. It was very active considering it's so early in the season," said Manutea Capt. Carlos Cardenas.

A "fluke" refers to the whale's tail, which often is displayed when the animal dives near the surface. A "peduncle throw" is when the whale lifts its rear half into the air then slams it down into the water.

"Everybody was really stoked. It's really kind of early for a sighting, which is kind of cool for us because it will be good for business," Cardenas said.

Whale-watching is a multimillion-dollar industry in Hawai'i. January and February are generally considered the peak time when whales are most numerous and active here, but they have been known to arrive as early as September and stay as late as June.

Early arrivals are typically single adult males, with other early arrivals including mothers with calves that were born in Island waters last season.

An estimated 5,000 to 7,000 humpback whales visit Hawai'i annually to socialize, mate and calve.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.