The World Wide Fund for Nature (WWF) will launch a survey of endangered finless porpoises on the Yangtze River, China\'s largest river, in November and December, the head of WWF\'s China office said Thursday. The 40-day survey, the first of its kind to take place in six years, comes after more than 20 finless porpoises were found dead on the Yangtze River and two nearby lakes earlier this year. The alarming deaths, which many believe were caused by pollution and human activity, have led some to worry that the porpoises could go extinct within decades if efforts are not made to preserve them. WWF, together with the Ministry of Agriculture and Institute of Hydrobiology under the Chinese Academy of Sciences, will analyze the animal\'s population and distribution and evaluate the threats it faces, according to Peter Beaudoin, head of WWF\'s China office. Based on the survey data, the agencies will offer suggestions regarding further protection efforts, including setting up new nature reserves, Beaudoin said. \"We just hope that the survey results won\'t be too pessimistic. We hope they will help to beef up protection efforts,\" said Wang Kexiong, deputy commander of the survey team. A 2010 WWF report blamed illegal fishing, inadequate water conservancy facilities and pollution for the declining freshwater dolphin population. Finless porpoises are on the brink of extinction, the report added. A 2006 survey showed that some 1,200 finless porpoises were left in the river. Just 600 porpoises were found in the nearby lakes of Poyang and Dongting. If strong measures are not taken, the number of porpoises could decline to 200 by 2035, scientists warned.