Specialists were surprised Thursday after a Sandtiger Shark ran aground on the French coastline of the English Channel, even though it is normally found in deeper and warmer waters.

The dead shark that authorities said weighed 200 to 300 kilogrammes (440 to 360 pounds) and measured 2.5 metres (8.2 feet) was found Monday evening by tourists at Agon-Coutainville before it was pushed back out to sea hours later.

"Encounters between man and the Sandtiger Shark are rare and do not occur in the English Channel," according to Eric Stephan, an official with the Association for the Study and Preservation of Selachians.

"One can observe it off the coast of Colombia. One also finds it off the coast of Australia, New Zealand and the Mediterranean," Stephan told AFP.

"This species feeds on fish and squid and has never been mentioned in accidents between humans and sharks," said the specialist who identified the shark from police and tourist photographs.

Stephan said the Sandtiger Shark resembles more the Greynurse Shark, often seen in aquariums, than it does the Tiger or Bull Shark that is blamed for attacking surfers in the Reunion, an Indian Ocean island belonging to France.

The case is "all the more surprising as it lives in deep waters," according to Samuel Iglesias, a specialist in sharks and rays at the Natural History Museum at Concarneau who spoke to the newspaper West France.

The beaching of sharks is much rarer than that of whales that have air in their lungs and tend to rise to the surface, experts said. Dead sharks tend to sink.

But the presence of sharks off the coast of France, including in the English Channel, is not a surprise as more than 30 species have been spotted there, Stephan said.

In the absence of an autopsy, experts said, the causes of the beaching are difficult to establish. It cannot be ruled out that the animal was ill and its orientation system failed.

But from "time to time one finds cases of species turning up where one doesn't expect them," without it happening again or without necessarily providing signs that the ecosystem is out of kilter, Stephan said.