A team of wildlife experts will visit a number of Scottish islands in their efforts to discover what has caused the deaths of the seal pups.
Haunted by the memory of an outbreak of distemper in 1988, which killed 19,000 of Britain's seals, wildlife experts also plan to have post- mortem examinations carried out to see if a virus is responsible.
The 37 common seal pups were found around the small uninhabited island of Damsay, which normally has a seal colony of around 200.
At first conservationists suspected they had been killed illegally, but are now less sure. Possible causes include a virus, a problem with their foodstocks, or other ecological disturbance.
Ross Flett, who runs a seal rescue sanctuary on Orkney, said yesterday: 'It is very unusual to see this number of deaths. The last time I remember seeing anything like this was in 1988. I am very concerned, and will be until we find out exactly what is happening.'
He plans to travel with wildlife experts to other Orkney isands to see if the problem has spread there.
Britain has a population of common seals totalling 28,000, a quarter of which are around Orkney. However, common seals are heavily outnumbered by grey seals, whose total British population - mostly in Scottish waters - could exceed 100,000.
Fishermen have been pressing for a cull of grey seals, blamed for eating up fish stocks, but this has been rejected by the Government. In 1989, about 19,000 seals were killed by a distemper- like virus that threatened to wipe out Europe's seals.