Green groups on Tuesday launched a legal challenge against the Canadian government’s approval of genetically modified (GM or GMO) salmon egg manufacturing, which they say was done in secret, violated environmental protection laws, and risks widespread, long-term damage.

“Canadians expect government decision-making to be open and transparent, especially when it comes to something as significant as manufacturing genetically-modified salmon that may pose serious risks to wild Atlantic salmon stocks,” said Kaitlyn Mitchell, an attorney with the environmental law firm Ecojustice. “This decision should have never been shielded from public view.”

With salmon at historically low numbers in parts of the Atlantic, the plaintiffs argued (pdf) that approving GMO salmon manufacturing violated the Canadian Environmental Protection Act, which requires new substances to be tested for toxicity to the surrounding ecosystems.

If they are slated for human consumption, GMO salmon would become the first genetically modified food animal in the world—and about five percent of them would be able to breed in the wild, Ecojustice said Tuesday.

“Approval of the world’s first genetically-modified food animal essentially happened behind closed doors, with zero public input,” said Mark Butler, policy director at Ecology Action Centre, a Nova Scotia-based conservation group. “Not only was the public left out of the loop, there has been no consideration of whether these genetically-modified salmon could become invasive in the event of an escape.”

Under then-Prime Minister Stephen Harper, the Canadian government in 2013 approved a bid by American biotechnology firm AquaBounty to manufacture GMO salmon eggs on Prince Edward Island (PEI). From there, the eggs will be shipped to facilities in Panama and grown to adult size.