The grim sight is baffling.

Marine biologists who are investigating after it least six whales were found washed up with no apparent sign of having been hit by a ship or caught in a trawler's net.

Researchers on Monday used a mechanical digger and long knives to dissect a mammoth fin whale, taking samples they believe might reveal evidence of a viral pathogen.

They say that in an average year between three and at most, 10 whales have found dead on France's beaches.

Willie Dab in is a researcher from the Pledges Observatory.

We have what is almost an epidemic or at any rate, a spike in deaths, which doesn't seem to be normal compared to what we've observed for the last 50 years in our tracing of washed up whales, The most recent fin whale corpse was found on Friday.

The common fin whales have all died within the past six weeks, and all of them have been malnourished and shown evidence of hemorrhaging.