Indo-Pacific humpback dolphins, also known as white dolphins or pink dolphins, have returned to parts of the Pearl River Delta in Hong Kong – and their revival is attributed. Researchers say the number of these dolphins off Hong Kong has risen 30% due to a break in ferry traffic in recent months.
The dolphins moved back to parts of the river that they once avoided because of the ferries that were supposed to carry passengers from Hong Kong and Macau, said marine scientist Lindsay Porter of the University of St. Louis. Andrews according to Reuters.
Ferry traffic was suspended in March, which also allowed researchers to investigate how underwater noise affected their behavior, Porter said.
Porter and her team throw microphones from a boat and use drones to keep an eye on the dolphins. Their research suggests that dolphins are rapidly adapting to the quieter environment, and now the population of the river is likely to jump back.
This type of dolphin was first recorded in local waters as early as the 17th century, according to WWF Hong Kong. The population of the Pearl River estuary is estimated to be around 2,500 individuals, but the organization says there has been a “worrying decline” in recent years.
“I sometimes feel like we’re studying the slow death of this population, which can be really sad,” Porter was quoted as saying by Reuters.
WWF Hong Kong says threats to these dolphins include overfishing, water pollution and heavy ship traffic and coastal development. However, research in this area could also help dolphin populations elsewhere, Porter told Reuters.
CBS News has reached out to Porter at the University of St. Louis. Andrews for more information.