Japan should stop harpooning whales for scientific research, the WWF environmental group said on Sunday in a report denouncing the slaughter as a cover-up for commercial sales of the mammals' meat, Reuters reported. Japan should instead collect whale skin samples for genetic analysis using non-lethal darts, the WWF said in a 44-page report about Japan's whaling programmes. "It is extraordinary that Japan, one of the most technologically advanced nations in the world, continues to kill an estimated 650 whales a year using 1940s science," said Susan Lieberman, director of the WWF's global species programme. "We call on Japan to live up to its reputation as a technologically and scientifically advanced nation, and put an end to 'scientific whaling'," she said in a statement carried by Reuters. Whaling nations -- mainly Japan, Norway and Iceland -- are allowed to kill whales for scientific purposes under rules of the International Whaling Commission (IWC) even though the IWC imposed a moratorium on all commercial hunts in 1986. Yet meat from whales caught for research often ends up in restaurants or shops after the scientists have done their work, leading many opponents to see the catches as a sham to circumvent the IWC moratorium. --More 0045 Local Time 2145 GMT