As carcasses continue to wash up in the isolated coves where seals return each year to breed - the number of bullet-ridden bodies now exceeds 30 - everyone has their own idea. Suspicion centres on local fishermen. "Who else could it be?" asks a drinker at the Moray Arms in St Margaret's Hope. The man, who will not reveal his name, explains. "The fishermen are always complaining that the seals are taking their catch, and so are asking for a cull. Well, now some frustrated person has taken the law into his own hands. And the young seals were easy targets."
The sight of the 25 white pups lying on blood-spattered rocks at Green Head, Burwick, provoked angry protests from animal rights groups and the public at large this week. But to Orcadians, news of the slaughter came as no surprise. Each year carcasses are washed ashore, some with gunshot wounds, others decapitated. No one has ever been convicted of killing the protected species, and public protests have so far been muted.
The scale of the latest killings, however, has forced into the open the bitter argument between environmentalists and fishermen over the need for a seal cull to protect fish stocks in one of Britain's most important fishing grounds. As they began the task of removing the young seals from the shoreline, animal rights activists were quick to rubbish renewed calls from the fishing industry for a licensed cull. Radical campaigners in Glasgow even called for a consumer boycott of fish from Orkney.
The debate is an emotional one. To many, the idea of shooting the fluffy, big-eyed, lumbering mammals is horrific. But fishermen insist our view of seals is too romantic. They claim the animals eat 244,000 tonnes of fish each year - more than Britain's entire EU catch quota for white fish. They steal bait and lobsters from creels and harm fishing lines. Trawlermen and fish farmers insist that seals threaten the livelihood of the 600 Orcadians who depend on the pure Atlantic waters to make a living.
Geordie Costie, a spokesman for the Orkney Fisheries Association, has fished off Orkney all his life. He used to hunt seals himself before the mammals were designated a protected species in 1970 under the Conservation of Seals Act. After the latest shootings, he called for a licensed cull. He condemns the weekend massacre but says he understands fishermen's "deep frustration" at the increase in seal numbers. The association estimates that since the last large-scale official cull was abandoned in 1978 after protests from Greenpeace, seal numbers off Orkney have doubled from 60,000 to about 120,000. With few predators except man, seal numbers look set to double again by the end of the century.
"No one wants to exterminate seals," Mr Costie says. "But we want to see numbers controlled in the same way that red deer numbers are limited in the Highlands. Most people now have grown up in cities and I can understand that if they see a picture of watery-eyed seals, they get watery-eyed themselves. But seals are not cuddly pets. They are wild animals with voracious appetites. People who have to live out here and who have hauled in their creels, fishing gear or lines to find yet again that they have a meagre catch, see them as pests. What's needed is the humane control of numbers to restore the correct environmental balance. It's the only way. We have to protect our way of life."
As the Scottish Office prepares to look again at proposals to reduce seal numbers, animal rights campaigners say the prospect of Scottish and Norwegian marksmen taking to the water in inflatables and shooting seals as they bask on rocks and beaches is horrifying. In principle, they do not oppose a humane cull. They acknowledge that although they are a protected species, grey seals are not under threat. They only enjoy protection because Britain has two-thirds of the world's seal population and, therefore, has a responsibility to maintain stocks.
But the campaigners claim killing seals will not solve the fishermen's problems. Evidence that seals are responsible for the recent reduction in fish stocks is purely anecdotal. Ross Flett, chairman of Orkney Seal Rescue (which monitors attacks on seals), points to recent studies by scientists at Aberdeen University. These show that seals do not feed on the same fish - cod, haddock, salmon - that the fishermen catch, but opt instead for sand eels and squid. The scientists also argue that other animals may be damaging lines and creels.
"Seals are blamed for everything round here," says Mr Flett, "and there is simply no hard, reliable evidence to support it." He insists that fishermen are citing seal mischief to cover up their own mistakes. "There's no doubt that man is mainly responsible for declining fish stocks. Over-fishing, pollution and acid rain should be tackled before we start culling animals. The fishermen, who by their own admission throw away as much as 40 per cent of their total catch before they reach port, to comply with EU quotas, should change their working habits before lobbying for renewed killing. They are looking for scapegoats."
The issue will be discussed next week when the Wildlife and Country Link Seals Group, which represents most of Britain's marine conservation bodies, holds its annual meeting in Edinburgh. The conference will call for laws on seal protection to be tightened, with increases in penalties for those convicted of illegally killing seals.