In a rare piece of good news for whales, humpbacks who live and breed in the southern oceans near Antarctica appear to be making a comeback, with females in recent years having a high pregnancy rate and giving birth to more calves.

Humpback whales were nearly hunted out of existence in the late 19th and most of the 20th centuries until treaties were signed to stop killing them and protections were put in place for the world’s coldest, least accessible continent.

The end of hunting has fostered the recovery of the school-bus-sized animals whose life spans are roughly comparable to ours, according to Ari Friedlaender, an associate researcher at the University of California Santa Cruz, who led the new study.

The population was believed to have been reduced to less than 10 percent of it pre-whaling levels.

To determine gender, identity and pregnancy rates, the scientists, led by Logan Pallin, a doctoral student working with Dr. Friedlaender, used darts to take small skin and blubber samples from 239 males and 268 females from 2010 to 2016 around the Western Antarctic Peninsula.