BRUSSELS, March 18 (Reuter) - United Nations data saying that millions of tonnes of unwanted fish are dumped overboard each year are open to doubt, EU Fisheries Commissioner Emma Bonino told a Tuesday news conference. "I always have some doubts about the enormous quantities talked about. They would mean we had an enormous fish stock, which is not the case," Bonino said. Her remarks were in reply to questions about U.N. data released on Monday saying quantities of dumped fish in Atlantic fishing grounds could reach one half of all demersal (sea-bed-living) fish caught in those areas. Fishing boats around the world frequently dump overboard tonnes of dead fish from low-value species or those which have been caught in excess of alloted quotas. The practice infuriates environmentalists, who say it damages stocks in the EU's already fish-depleted waters, and has led EU neighbour Norway to propose a ban on the dumping of certain threatened species. "The ban is not something which can be monitored or which will be

very convincing," Bonino told the news conference called to encourage EU citizens to eat more fish from less-glamourous species like sardines, mackerel and herring. She singled out her fellow Italians as having a tendency to turn up their noses at these less-fashionable fish. "For Italians, fish must look like fish... it cannot just be a slice of fish because that's not really a fish," said Bonino, a self-confessed squid lover, which she said she sometimes catches herself. The European Commission campaign, worth 1.7 million Ecus ($2 million), will include a multi-country road show, a competition for schools to design television adverts or short films on the campaign themes, conferences and various other promotions.