EVERY SPRING THE clatter of helicopters shatters the silence of the frozen Gulf of St. Lawrence. The big machines settle down on the ice floes, and the world’s bloodiest and most brutal annual massacre is once again under way.

The men jumping out of the helicopters are armed with clubs and hobnailed boots. Their targets are thousands of mother and pup seals waiting on the ice for the males to return from sea. As the mothers stand fast to protect their young, the hunters move behind them, clubbing and kicking the squealing pups senseless. Then as the snow turns red with blood, the skinning begins. At least 50,000 seals — probably many more — will die before the hunters have enough skins for the year.

For years periodic protests have trickled into Ottawa about the seal hunt. And for years the Canadian government has replied to outraged animal lovers that adequate precautions are taken to ensure as little suffering as possible.

But this year the traditional trickle of protests turned to a torrent. Hundreds of letters poured into Ottawa from across the world. In Germany, Scandinavia and India, harassed Canadian embassy officials were kept busy sending placating replies to irate letter writers. And in the House of Commons Fisheries Minister H. J. Robichaud was forced to reply to questions from concerned MPs.

It soon became apparent that a world-wide campaign against the seal hunt was under way. And it seemed to stem from a Canadian film shown on German television. The film showed the wholesale butchering of seals — its dramatic climax was a baby seal running around screaming its head off after being skinned alive. Government officials reacted quickly. The film, they implied, was spurious — no official Canadian film had been made on the subject and any film that did exist was without official approval.

But the film did exist — in fact two films exist. Both were commissioned and broadcast by the CBC French network. And among those who originally saw the films on television was Peter Lust, the editor of Montreal’s Germanlanguage weekly, the Montrealer Nachrichten.

For Lust, the film evoked a memory. He left Germany in 1933 but in 1945 he returned with the U. S. army. He saw Dachau and Buchenwald — and he vowed if he ever saw anything like it again he’d devote his life to fighting it. When he saw the seal films he felt his moment had come.

He wrote a blistering series of articles for his own paper, then sent them to the Hamburger Abendpost, which published them in full. Two masscirculation German weeklies, Wochenend and Heim und Welt picked the story up and soon it was appearing in newspapers across Europe. Then the West German television system asked the CBC for a copy of the film. The CBC said it would release it if both films were shown. Officials felt the second film showed a fairer picture of the hunt and they didn’t want the atrocity story shown by itself.

The German TV officials balked at this, so Lust indirectly arranged for Artek Film Productions Ltd., the makers of the film, to send a copy directly to a German friend. Dr. Bernard Grzimek, head of the Frankfurt zoo. Grzimek was so outraged he formed a society called “Campaign Against the Apathy of the Canadian Government.” He also got

the film on German television — and that’s when the letters started rolling into Ottawa and the Canadian embassy in Bonn.

Meanwhile in Canada the government had announced that despite its contention that all was well with seal hunting, new regulations were being enforced to ensure a minimum of brutality. One new regulation stipulated that only cluhs of “lethal size” should be used by hunters. Another set a 50,000 limit on the number of seal pups killed each year.

Serge Deyglun, the outdoors editor of Montreal’s La Presse who wrote the original film, calls the new regulations “sheer drivel.” He went out to the Gulf last year after they went into effect and found things the same as always. “It was an indescribable mess.”

At this point the Montreal SPCA got into the act. They claimed Deyglun was a mischievous publicity seeker. The society said its inspector reported no such brutality. Deyglun shot back in his newspaper column: “Band of cowards! Where were you when the seal flocks were being annihilated?” The SPCA was forced to admit its man had in fact arrived after the pups were massacred.

Dr. A. W. H. Needier, deputy fisheries minister, says a certain amount of public concern is inevitable in any industry which involves killing animals. “Especially when you’re dealing with rather nice soft little animals with big brown eyes.” But he insists that his department provides adequate supervision to ensure fair play by hunters. Officials are stationed at all boat and aircraft landing points, he says, and the government also runs an air patrol.

Needier claims clubbing is the most efficient and humane way of killing baby seals — “We’ve discussed it with the humane societies and they've been unable to come up with anything better.” And he claims there are good reasons for allowing an annual kill of

50,000. “We’ve been studying conservation of seals for 20 years and 50,000 is an easily sustainable kill. It’s nonsense to say herds are being decimated.”

He says Deyglun’s claim that seals are skinned alive is “complete and absolute balderdash — there’s no reason for it and it isn’t done.”

All this fails to satisfy Deyglun. This year he and Lust are returning to the Gulf. “This time for sure the world is going to find out if brutalities are still being carried out,” says Lust.

And if they are, both he and Deyglun don’t intend to keep quiet about it.