The Georgia Aquarium has not given up on its effort to import additional beluga whales into the United States, and presented arguments in federal court Wednesday supporting its case.

Appearing before U.S. District Judge Amy Totenberg of the Northern District of Georgia, the aquarium’s attorney, Daniel E. Diffley, argued that elements of the government’s decision-making process should be made public, to reveal why a federal agency reversed its course and decided against granting the aquarium a permit to import the whales.

In 2012 the aquarium applied to the National Oceanic and Atmospheric Administration for a permit to import the wild-captured whales, but was denied. Last October the aquarium filed suit, seeking a ruling in federal court to compel granting of the permit.

The aquarium wants to acquire 18 belugas captured in the Sakhalin-Amur region of the Sea of Okhotsk, off the east coast of Russia. The application for a permit to import the whales triggered enormous opposition from animal rights activists. Wild-captured belugas haven’t been imported into the U.S. in more than 20 years.

Georgia Aquarium President David Kimmel said earlier that NOAA Fisheries appeared ready to grant the permit, going as far as preparing a draft permit and undertaking an environmental assessment, when it reconsidered and denied the permit.

The aquarium is seeking documents pertaining to that change of direction, to determine the reasoning behind the denial.

“Something was going on at the agency that is not explained in the record,” Diffley said.

NOAA’s attorney, Ethan Eddy, countered that the requested documents would violate the right of the agency to have its deliberations shielded from public view. Such exposure would “discourage candid discussions within the agency and otherwise undermine the agency’s ability to perform its function,” he said.

Eddy and Diffley also sparred over a request by the aquarium that NOAA accept three additional studies on whale populations into the permit application, and they briefly presented differing interpretations of the impact that importing the whales would have on wild populations.

Caught by Russian collectors in the years 2006, 2010 and 2011, the snow-white cetaceans are being held at Russia’s Utrish Marine Mammal Research Station.

The Georgia Aquarium hopes to import the whales to add to the breeding stock being held in human care at six different facilities, including three SeaWorld parks and the Shedd Aquarium in Chicago.

The aquarium currently has four belugas in its collection.

At the close of the two-hour hearing Totenberg told the attorneys she would render a decision sometime in the near future.