A US federal judge has blocked the controversial importation of 18 captured beluga whales off the coast of Russia in 2013.

Georgia Aquarium first applied to import the whale pod in 2012, saying it would help diversify its existing beluga gene pool in the US. However, the National Oceanic and Atmospheric Administration Fisheries (NOAA) denied this application in August 2013, leading the institution to sue NOAA for the right to acquire the beluga whales.

NOAA denied the permit on the basis that the aquarium failed to meet the requirements of the Marine Mammal Protection Act, arguing that the aquarium did not ensure that the capture of the belugas – caught in the Sea of Okhotsk and currently under the care of a Russian team – would be unlikely to have an adverse effect on the beluga population in the area where they were sourced.

The ruling is a victory for wildlife and conservation groups, which will now prevent the captured whales from being brought to the Georgia Aquarium in Atlanta and other parks that were interested in acquiring the cetaceans, including SeaWorld.

US district judge Amy Totenberg, who issued a written ruling denying the importation of whales, said the aquarium had accused NOAA of “cooking the books’ to fabricate its rationale,” for denying the permit but added that "beyond all the smoke and mirrors, Georgia Aquarium's arguments boil down to an attempt to shift the burden of proof to (the government)."

The aquarium has the right to appeal and for the meantime the whales will remain in the custody of the Russian team. Georgia Aquarium declined to comment on the ruling, only saying that it was “reviewing the decision”.