An alliance of US environmental groups is preparing to ask Washington to ban imports of Canadian snow crab unless Ottawa steps up its efforts to save the endangered Atlantic right whales.

Another right whale was found dead in the Atlantic this week, bringing to 16 the total number of the endangered mammals that have died off the East Coast of Canada and the US this summer.

Examinations show most of the whales died after being hit by ships or getting tangled in fishing gear. Thirteen of those deaths occurred in Canada's Gulf of St. Lawrence.

Kristen Monsell, a senior lawyer at the Center for Biological Diversity, says a provision of the US Fishermen's Protection Act allows the White House to ban imports of seafood from a country if that catch is affecting conservation efforts of an endangered species.

Monsell says snow crab is the target, because Canada has no mandatory regulations in place for snow grab gear or lines that could help keep whales from getting caught in them.

Canada itself has acknowledged seven whales got tangled in snow crab lines this summer, and two of them died.