A Hong Kong airline has promised to stop transporting live dolphins after coming under heavy criticism from animal welfare activists, conservationists said Wednesday. More than 6,500 people have signed an online petition urging Hong Kong Airlines to stop the business, revealed when an internal memo about a recent delivery from Japan to Vietnam was leaked to Chinese media. \"Hong Kong Airlines wishes to convey that it is a responsible member of the transport industry caring for the future and environment,\" the airline said in a letter to animal welfare groups dated Wednesday. \"Since it is believed that transportation of this nature can result in endangering wildlife elsewhere, Hong Kong Airlines will immediately ban shipments of this kind,\" the letter stated. A copy of the letter was posted on US-based conservation group Sea Shepherd Conservation Society website. Representatives from the group have written to the airline denouncing the dolphin shipment. Hong Kong Airlines in an emailed reply to AFP declined to comment. \"This action should send a message to all airlines that the consequences of transporting dolphins will result in such global negative publicity as to affect a loss of business that will far outweigh any short-term financial gain from the transfers,\" Sea Shepherd Hong Kong coordinator Gary Stokes said. The airline has said it complied with government rules and the International Air Transport Association regulations on live animal transportation during the January 16 delivery of the five dolphins from Osaka to Hanoi. The dolphins are believed to have come from the Japanese town of Taiji, the scene of an annual dolphin slaughter depicted in Oscar Award winning documentary \"The Cove\", said China Daily, which first reported on the delivery. The leaked memo said the flight earned HK$850,000 ($110,000) in cargo revenue. The China Daily report included a photograph of the dolphins lying in shallow, narrow containers inside the belly of a Boeing 733F cargo plane.