Rare dolphins returning as ferries pauseWorld | REUTERS 15 Sep 2020
The number of Indo-Pacific humpback dolphins seen around Hong Kong has jumped as the pause in high-speed ferry traffic due to the coronavirus allows the threatened species to make something of a comeback, scientists say.
Marine scientist Lindsay Porter of the University of St Andrews said the Chinese white dolphins and pink dolphins are moving back into parts of the Pearl River Delta that they typically avoided due to the ferries that connect Hong Kong and Macau.
Dolphin numbers in the area had jumped by up to 30 percent since March when the ferry traffic was suspended, allowing scientists a rare opportunity to study how underwater noise affected their behavior, she said.
"These waters, which were once one of the busiest thoroughfares in Hong Kong, have now become very quiet," said Porter, who has studied dolphins for three decades from Hong Kong.
From a small rubber boat, Porter and her team drop microphones into the water and use drones to watch for dolphins.
The research suggested the dolphins have adapted more rapidly than expected to the quiet environment, and the population is likely to rebound when such stressors are removed, Porter said.
A government survey from 2019 found only 52 dolphins entered the waters around Hong Kong but Porter believes the real number may be slightly higher.