Maris' other baby, born in 2012, also died - within a week.
The father of both babies was Beethoven. He is currently at Chicago's Shedd Aquarium on a breeding loan, according to the Atlanta Journal Constitution.
Maris was brought to the Georgia Aquarium in 2005. She was born in 1994 at the New York Aquarium.
These deaths come at a controversial time. For years, the Georgia Aquarium has been hoping to import 18 wild-caught beluga whales from Russia and distribute them to a number of aquariums in the U.S. The belugas were captured as far back as 2006, according to the Associated Press.
In September, a judge ruled against the Georgia Aquarium's effort to bring the whales into the country. The aquarium may appeal the ruling. All the while, the fate of the belugas in Russia remains uncertain.
There are some 150,000 beluga whales left in the wild. They live in Arctic and subarctic waters, with some regional populations especially vulnerable. Belugas were dubbed the "sea canary" by early mariners based on their inimitable vocalization, according to the Whale Dolphin Conservation (WDC) organization.
Beluga whales suffer in captivity, Courtney Vail, campaigns and programs manager at WDC, told The Dodo. "[They suffer] from the same physiological and psychological stressors and challenges in captivity as all cetaceans do, including sterile and restricted environments, forced associations, limited choices, transfers between facilities and aggression between pool mates."
Belugas also live far longer in the wild than in captivity. In the wild, belugas can live upwards of 60 years of age, Vail explains, based on research.
Back at the Georgia Aquarium, the beluga exhibit will remain open to the public. A necropsy will be performed on Maris.
The results are expected in a few weeks.