Alaska's humpback whales, federally protected for over 40 years, came close to losing their "endangered" status on Wednesday as reports surfaced of their growing numbers, a US agency said.

In a Feb. 26 petition, the State of Alaska asked the NOAA to delist the central north Pacific population of humpbacks, which migrate between Alaska and Hawaii, under the US Endangered Species Act (ESA). They cited population growth as a result of their "endangered" status and noted existing regulations that are still able to protect the animal.

At that time, the entire north Pacific population had been estimated at nearly 22,000 whales, up from just 1,000 in the late 1990s, and the central north stock was just under 6,000 whales, the NOAA reported.

The federal fisheries agency said Wednesday in a statement it found "substantial scientific or commercial information indicating that the petitioned action may be warranted."

This "positive ruling" comes after the agency's similar response in August when the Hawaii Fisherman's Alliance for Conservation and Tradition filed a separate petition requesting to delist all north Pacific whales.

Under the ESA, the NOAA's 90-day finding warrants validation of the humpback's comeback. They will do a year-long, comprehensive investigation of the species' status, taking into account projected population growth rates and threats, such as fishing gear and potential ship strikes, said agency spokeswoman Julie Speegle.

It will then make a decision whether to reduce the central north Pacific and entire north Pacific populations' status to "threatened," or to take no action at all, despite the petition.

Though, the agency is seeking public input about the matter until July 28, during which time opposition may arise, especially from environmental groups.

"Simply put, they no longer need ESA protection. They should be removed and effort focused on species needing protection," said Doug Vincent-Lang, an Alaska wildlife conservation official.