PORTLAND, Maine –  Sweden is digging in on a proposal to ban imports of live lobsters into the European Union after a rebuke from American scientists, and the issue could go all the way to the World Trade Organization.


Sweden asked the European Union to bar imports of live American lobsters into the bloc earlier this year after 32 American lobsters were found in Swedish waters. The U.S. government then told the European Commission that the proposal isn't supported by science, and American and Canadian scientists issued reports calling the Swedish claim into question.


Now, Sweden's Agency for Marine and Water Management is issuing a response to criticism, and says the country is right to be cautious about the appearance of a foreign species in its waters. The response came out at the end of July and defends the prevention of the spread of American lobsters as "environmentally desirable and cost-effective."


The Congressional delegation of Maine, the country's largest lobster producing state, issued a statement that said it will appeal to the WTO if the European Union ultimately sides with the Swedes.


Lobstermen in America and Canada, which together export $200 million worth of lobster to European markets each year, are hopeful that Sweden's call for a ban eventually amounts to nothing.


"I haven't taken my Swedish engine out of my boat yet," said Gerry Cushman, a Port Clyde lobsterman. "I'd like to see lobsters stay open throughout the world everywhere."


European Union's Scientific Forum on Invasive Alien Species is expected to express an opinion about Sweden's call for a ban on Aug. 31. The country has said American lobsters, which are fished off the coasts of the U.S. and Canada, could spread disease and overtake the smaller European variety of lobster.


Robert S. Steneck, a University of Maine scientist, wrote a paper that said the American lobsters that turned up in Europe were most likely released illegally, as opposed to migrating across the ocean. He also wrote that American lobsters don't pose a threat to European lobsters, in part because winter ocean temperatures along the coasts of European countries are too warm for the American lobsters to reproduce.


But Sweden's marine agency said it is "vital" to take a precautionary approach to the issue, because American lobsters' failure to gain a foothold in Europe thus far is "no guarantee that the same species will not be successfully invasive in another place or time." The agency also says more research is needed into the impact of cross-breeding of American and European lobsters.


Maine's congressional delegation said the European import market is critical to the lobster industry, and the state's leaders remain committed to supporting it. Maine's lobster industry was worth about a half billion dollars last year and catches have soared to record highs in recent years.


State leaders hope the EU "will strongly consider the evidence offered by North American experts and decide not to pursue a ban on imports of live American lobster to Europe," the delegation said in a statement.