Canada said it rejected a call from its own advisory committee to list the Atlantic bluefin tuna as a species “at risk” because the economic losses from a commercial fishing ban would have outweighed environmental gains.

Adding the Atlantic bluefin tuna to the list of species at risk would have had “significant and immediate socio-economic impacts” of C$10 million ($7.3 million) a year on commercial, sport and recreational fisheries, the government said.

In its May 3 decision, the government said...