ROME, July 1 (Reuter) - Angry fishermen heckled European fisheries commissioner Emma Bonino on Monday as she told Italy to respect international regulations or face a trade embargo from the United States. Several fishermen shouted down Bonino at a scheduled news conference in Rome, gesticulating at the commissioner and accusing her of refusing to meet them. Bonino had earlier said in a speech that a total ban on drift net fishing for tuna was essential. "The European Commission proposal for a total ban on fishing for tuna and sword fish with drift nets is the only viable option, however painful it may seem," she said. Bonino said patrols last month had found that 15 out of 16 Italian boats checked at sea were using drift nets on average twice the allowed length of 2.5 km (1.5 miles). The United States has threatened an embargo on Italian fish products if the fishermen do not operate within the law. "The American threats must be taken seriously," Bonino added, while saying that a ruling in the U.S. Court of I

nternational Trade in March that called on Washington to impose an embargo was outside the United States' jurisdiction. Current EU regulations limit the size of nets to 2.5 km but environmentalists say the continued use of drift nets by some 500 Italian boats is causing serious damage to other species. "The dragnets kill thousands of dolphins and dozens of sperm whales every year," said Greenpeace spokesman Alessandro Gianni. Bonino said it was essential to ban drift nets entirely, since nets within the legal limit were not economically viable and therefore most Italian fishermen were breaking the rules on a regular basis. "It seems illogical to maintain a way of fishing that has shown itself to be profitable only by breaking the rules," she said. The Italian government estimates such a ban would threaten 2-3,000 jobs in southern Italy, where unemployment stands at 22.2 percent. The fishermen say the number put out of work by a ban would be more like 10,000 people. The Commission's proposal for a total ban b

y the start of 1998 has been on the table since 1994, but has so far been opposed by all the member states except Spain and Greece.