Alaska’s humpback whales swam a little closer to losing their status as an endangered species after being federally protected for more than 40 years, a US agency said.

Alaska asked federal fisheries managers to scrap the ‘endangered’ classification of the central north Pacific population of humpbacks under the US Endangered Species Act (ESA), citing population growth and existing regulations it says protect the migratory mammals.

The National Oceanic and Atmospheric Administration (NOAA) said it found “substantial scientific or commercial information indicating that the petitioned action may be warranted”.

The so-called ‘positive ruling’ comes after the agency’s similar response in August to a petition by the Hawaii Fishermen’s Alliance for Conservation and Tradition, which sought to delist all north Pacific whales.

The Alaska-Hawaii findings mean NOAA will conduct roughly year-long reviews of the central north Pacific and entire North Pacific populations, to project population growth rates and threats, such as fishing gear and potential ship strikes, said agency spokeswoman Julie Speegle.

It will then deliver a decision whether to delist the whales, reduce their status to ‘threatened’, or take no action at all. Speegle was already reviewing a petition urging status review of global populations of humpback whales, which can live roughly 50 years.