HONOLULU - A new study says humpback whales have made a dramatic comeback from the brink of extinction in the North Pacific Ocean over the past four decades.

The study released Thursday by SPLASH, an international organization of more than 400 whale watchers, estimates there were between 18,000 and 20,000 whales in the North Pacific in 2004-2006.

Their population had dwindled to less than 1,500 before hunting of humpbacks was banned worldwide in 1966. Experts call the results very encouraging, but say the numbers don't yet indicate a complete success.

The whales are protected under U.S. federal laws, but experts say their resurgence could spark a debate over whether they should still be considered endangered.

The whale count was made based on data collected from Hawaii, Mexico, Asia, Central America, Russia, the Aleutians, Canada and the United States' northwest coast.