By Howard Pousner

The Atlanta Journal-Constitution

Tuesday, a black curtain covered the viewing window at the Georgia Aquarium’s Cold Water Quest gallery, but right before opening time, staff members couldn’t help but sneak a peek at the two huge stars swimming behind it.

The beluga whales are back at the downtown attraction, and if their adjustment continues to go well, they’ll make their public splash this week.

For the aquarium staff and visitors, it will be time to get reacquainted as well as time for an introduction. Longtime resident Maris, a female, has returned, joined by a newcomer, Beethoven, a male.

Why they left and what’s happened since is a complicated story.

Early last October, the aquarium moved its three belugas -- Maris, her mother, Natasha, and Nico, a male -- to Sea World San Antonio as a “preventative” measure due to construction. The media assumed and reported that the precaution was related to noise from the dolphin-related expansion adjoining the whales’ exhibit, which the aquarium had been closely monitoring. Officials never clarified otherwise.

But after Nico died suddenly of unspecified causes on Oct. 31, chief veterinary officer Dr. Gregory Bossart acknowledged the whales were moved so that Cold Water Quest could undergo minor renovations while dolphin construction was ongoing.

Aquarium officials now say that rock ledges were added along the pool’s edge to allow better access for animal care staff and to allow visitors to participate in an encounter program with the belugas. The aquarium has not set a start date for the program, in which a small number of guests can interact with the whales beside a trainer.

Cold Water Quest remained closed until four harbor seal pups were added to the aquarium’s population in February. Now, the harbor seals have been taken off view until 15-year-old Maris and Beethoven, 18, can get acclimated in their Atlanta digs.

The ghostly white whales, flown in from Texas in containers on a FedEx cargo plane, swam with typical grace Tuesday morning as New Age music swelled in the viewing area.

Earlier this summer it appeared as though two different belugas were headed to Atlanta, male juveniles from Sea World San Antonio. But as time passed, it became possible to bring in a potential mating pair in 11-foot-long, 900-pound Maris and 13-foot, 1,740-pound Beethoven, himself born in captivity at Sea World San Antonio.

Still, aquarium senior vice president and chief animal officer Billy Hurley played down romance as a motivator of this particular pairing.

“Breeding had little to do with why these two were selected,” Hurley said, citing "compatibility" as the main factor. “However, managing the beluga population to maximize genetic diversity and to increase numbers of individuals is always considered criterion.”

Because there are only 36 belugas in North American captivity, the six facilities that house them are essentially partners who manage the individuals as one large collection. Officials from each even meet annually to discuss breeding, long-term loans and short-term moves due to renovation or other reasons.

Thus, Natasha, who came to the Georgia Aquarium when the New York Aquarium decided it would no longer keep belugas in its collection, will remain in San Antonio because a potential mate has been identified there.

“Who actually owns the animals is not as critical as the management biologically of the population,” Hurley said. “There are only 36 of them. If there were 4,000, it’d be less critical. [None of the partners] is worrying about what number or color jersey [the whales] are wearing. We’re all on the same team.”

The six aquariums caring for belugas, in addition to Georgia Aquarium and Sea World San Antonio, are Sea World Orlando, Sea World San Diego, Chicago’s John G. Shedd Aquarium and the Vancouver Aquarium in British Columbia.

Hurley called the death of Nico, whom the Georgia Aquarium had rescued in 2005 from a Mexico City attraction, “devastating.” Nico was estimated to be more than 25 years old, and beluga lifespans are typically believed to be 25 to 30 years.

The chief animal officer said the aquarium has “no targeted number” of belugas it hopes ultimately to display, but that “guest response demonstrates the hope of seeing more animals.”