A 5-metre long whale shark was spotted in Ang Thong national marine park in Samui district of Surat Thani province yesterday, the park chief said.
Mr Apichart Na Nakhon, chief of the Ang Thong national marine park, said this is the fourth time since last month that whale sharks were spotted in the marine park.
This could be a proof of the bio-richness of the southern sea, he said.
He said the latest sighting is a baby whale shark as it is only five metres long.
However the appearance of the baby whale shark has excited tourists on boats visiting the marine park yesterday.
He said the park officials on a patrol boat has video taped the baby shark as it was as swimming nearby.
The park rangers on the boat then warned tour boat drivers to keep a distance from the whale shark as their boat propellers could harm it, he said.
He went on saying that whale sharks were not sighted previously in the marine park until September this year.
He said whale sharks will normally swim close to any moving objects.
He then ordered all park officials to inform all tourist boat operators and speedboats to switch off their boat engines for the safety if they sight the animal coming close.