A group of Hawaii fishermen has petitioned the National Oceanic and Atmospheric Administration to remove humpbacks (known as kohola in Hawaii) from the endangered species list, claiming that the population has steadily grown since the international community banned commercial whaling almost 50 years ago.

Today, there are more than 21,000 humpback whales in the North Pacific and about 60,000 around the world. When the commercial whaling ban was first implemented, there were only 1,400 in the North Pacific.

More than half of the humpback whale population spends the winter breeding and calving in Hawaii’s warm waters. Other North Pacific humpbacks winter off Mexico, Central America, Japan and the Philippines.

The fishermen believe the commercial-whaling ban and other regulations would continue to protect the whales despite their loss of endangered status. The petition is seeking delisting for whales only in the North Pacific.

The last time a species’ recovery prompted delisting was in 1994, when the agency removed the eastern North Pacific population of gray whales from its endangered list.

“It could be an important success story for humpback whales, but NOAA should really proceed with caution because of the overarching threats — ship strikes and fishing-gear entanglements — to make sure the gains aren’t unraveled,” says Miyoko Sakashita, an attorney for the Center for Biological Diversity.