PORTLAND, Maine (AP) — One of the rarest whales on the planet has continued an encouraging trend of population growth in the wake of new efforts to protect the giant animals, according to scientists who study them.

The North Atlantic right whale now numbers an estimated 384 animals, up eight whales from the previous year, according to a report by the North Atlantic Right Whale Consortium released Tuesday. The whales have shown a trend of slow population growth over the past four years.

It’s a welcome development in the wake of a troubling decline in the previous decade. The population of the whales, which are vulnerable to collisions with ships and entanglement in fishing gear, fell about 25% from 2010 to 2020.

The whale’s trend toward recovery is a testament to the importance of conservation measures, said Philip Hamilton, a senior scientist with the New England Aquarium’s Anderson Cabot Center for Ocean Life. The center and the National Oceanic and Atmospheric Administration collaborate to calculate the population estimate.

New management measures in Canada that attempt to keep the whales safe amid their increased presence in the Gulf of St. Lawrence have been especially important, Hamilton said.

“We know that a modest increase every year, if we can sustain it, will lead to population growth,” Hamilton said. “It’s just whether or not we can sustain it.”

Scientists have cautioned in recent years that the whale’s slow recovery is happening at a time when the giant animals still face threats from accidental deaths, and that stronger conservation measures are needed. But there are also reasons to believe the whales are turning a corner in terms of low reproduction numbers, Hamilton said.

The whales are less likely to reproduce when they have suffered injuries or are underfed, scientists have said. That has emerged as a problem for the whale because they aren’t producing enough babies to sustain their population, they’ve said.

However, this year four mother whales had calves for the first time, Hamilton said. And some other, established mother whales had shorter intervals between calves, he said.

In total, 11 calves were born, which is less than researchers had hoped for, but the entry of new females into the reproductive pool is encouraging, Hamilton said.

And any number of calves is helpful in a year of no mortalities, said Heather Pettis, who leads the right whale research program at Cabot Center and chairs the North Atlantic Right Whale Consortium

“The slight increase in the population estimate, coupled with no detected mortalities and fewer detected injuries than in the last several years, leaves us cautiously optimistic about the future of North Atlantic right whales,” Pettis said.  ”What we’ve seen before is this population can turn on a dime.”

The whales were hunted to the brink of extinction during the era of commercial whaling. They have been federally protected for decades.

The whales migrate every year from calving grounds off Florida and Georgia to feeding grounds off New England and Canada. Some scientists have said the warming of the ocean has made that journey more dangerous because the whales have had to stray from established protected areas in search of food.