A Hong Kong shark expert has criticised the government contractor for dumping two shark carcasses before scientists and officials had a chance to study them. Marine biologist Andy Cornish - conservation director of green group WWF - also urged the public not to overreact to the discovery of the sharks off Shek O beach, saying the species identified from photographs was not dangerous to humans. Contractor Universal Nets disposed of the silky sharks' carcasses and gave officials only photographs for their records. 'The body should always be kept so experts can identify it,' Dr Cornish said. 'Now that they have thrown the bodies away, we can't get the information.' Hong Kong's shark species had mostly died out, making it difficult for marine biologists to study the animals, he said. 'We don't know much about sharks in Hong Kong, they are so rare now,' he said. He had asked the Leisure and Cultural Services Department to keep better records of sightings, including species and locations, but nothing had changed. 'Apart from species' names, there is not much information about where they are found. A lot of our studies are done with specimens collected from fish markets,' Dr Cornish said. He said there was no need for the public to be alarmed as the sharks found off Shek O were not killers. Silky sharks, or Carcharhinus falciformis, are common in tropical areas around the world and feed on fish such as tuna. Dr Cornish said adults, which could reach three metres, were common in open oceans but only juveniles, such as those found, came close to shore.