A census should be taken on the Blasket Islands to establish the exact seal population after around 60 were bludgeoned to death, it was urged today.
The Green Party condemned the horrific attack, highlighting that it was an offence to hunt and kill seals under the Wildlife Act, 1976.
Environment spokesperson Mr Ciaran Cuffe TD said: "It is crucial to act quickly in order to protect and maintain the seal population on the Blaskets.
"Conservation officers fear that the attacks on Beginish could have wiped out most of this year's pups which if true will have disastrous consequences on the overall seal population level".
The Blaskets are one of the main breeding grounds for grey seals, up to 20,000 of which migrate from Scotland annually.
The Irish Seal Sanctuary found the dead animals, most of them pups, on the western side of Beginish Island last week.
The organisation said some had been shot, some bludgeoned and some may have had nails driven into their heads.
Mr Cuffe said that the number of sustained attacks over the years meant the seals were now in serious danger of becoming extinct.
He said estimates indicated that fewer than 400 grey seals now live on the islands compared to about 2,000 only 50 years ago.
"We are calling for a proper island-wide census to be taken to provide accurate figures for the current seal population in the area," the Dun Laoghaire TD added.
"Sustainable management strategies can then be put in place to protect the seals." It is not known who carried out the attack.