By Peng Junjun

At about 9 am on 28th October, standing at the riverside walkway of Fanyin Square of Binjiang Park and looking to the south, at about 150 m from the bank, an obvious yellow ship-shape buoy was floating up and down with the wave. Two meters below the water surface, the intelligent hydrophone suspended at the bottom of the ship-shape buoy was collecting acoustic signals from the finless porpoises. ‘With the pair of “ears”, once finless porpoises appear, we can hear their whispers.’ Gu Hongyu, a staff member of the Municipal Bureau of Ecology and Environment said.

Xin Yu, an engineer of Nantong Environment Monitoring Center, said that from January to October, in the water area near Langshan Mountain, 48 finless porpoise activities and more than 139 finless porpoises were observed. ‘Smiling angel’ finless porpoise has become a frequent guest in the riverside area of Nantong.

Then how many finless porpoises are there in the Nantong section of the Yangtze River? Where are they? The equipment installed under water can give answers.

Finless porpoises get above water for only 0.85 seconds usually. If only based on above water observation, the data acquired are very limited.

With the system, there is no need to wait for finless porpoises to get above water. As long as they appear in the water area monitored, the sound made will be ‘caught’ by the equipment at once. At the same time, the equipment will research and tell the azimuth and number of finless porpoises, obtain the travel path of finless porpoises, mark the exact positions of their appearance, and upload relevant information and videos to platforms, to let relevant departments get to know the population, activity patterns, living habits, and health conditions of the finless porpoises in the Nantong section of the Yangtze River more accurately, and provide more detailed and accurate data monitoring support to protect the ‘smiling angels’.

The equipment is only used in monitoring of finless porpoises. It will not interfere the normal habitat of finless porpoises.