Leading conservation groups have called on the government to take urgent action to save Hong Kong's pink dolphin population from the twin threats of pollution and reclamation. WWF Hong Kong called for an interdepartmental task force to be set up to find ways to save the dolphin population and for steps to be taken to halt reclamation projects they fear could push the mammals to the brink of extinction in Hong Kong waters. The Ocean Park Conservation Foundation, meanwhile, called on the government to do an urgent environmental assessment before allowing any further reclamation that threatens the dolphins. The foundation said there had been an "alarming decline" in the overall pink dolphin population in the Pearl River estuary, with numbers falling at a rate of nearly 2.5 per cent a year - which could see them all but vanish in a few decades. The Sunday Morning Post reported last weekend that pink dolphin numbers in Hong Kong - which have already fallen from 158 in 2003 to 78 in 2011 - will show an all-time low when 2012 figures are released next month. Sightings of dead calves have also risen sharply, with three cases recorded last month alone. The calves are suspected to have died from drinking contaminated milk produced by their mothers. Samantha Lee, senior marine conservation officer for the WWF, called on the government to abandon reclamation work in the western waters of Hong Kong, where she said dolphins were being driven away. "There are too many reclamation works and we are worried the threat will increase and the dolphins will one day disappear from our waters," Lee said. She called for an interdepartmental task force, saying: "The government needs to do something now that the situation isn't too serious. At the moment, this situation can still be reversed. This is a golden time for the government to react quickly. The pink dolphin was Hong Kong's mascot at the time of the handover. It is a symbol of Hong Kong and they are an indicator of the sea's health." The Ocean Park Conservation Foundation said projects including the proposed third airport runway and the Hong Kong-Zhuhai-Macau bridge posed "significant environmental and ecological impacts" to the pink dolphin habitat. "[We] strongly recommend that the government and the stakeholders conduct a thorough environmental impact assessment with … evaluation of the accumulated impact assessment of the proposed development areas," a statement said. The government insists it is already doing what it can to ensure that the effect of reclamation and development on the pink dolphin population is kept within "acceptable levels". A spokeswoman for the Agriculture, Fisheries and Conservation Department said the department had plans to designate more marine parks with a view to better conserving the dolphins. "To improve ecosystems in marine parks and offer better protection for marine organisms, we also propose to ban commercial fishing in marine parks," she said.