Chinese white dolphins, also known as pink dolphins for the color they attain when they swim in warm waters, are native to Southeast Asia, and hold a special place in the hearts of the people of Hong Kong.

But Hong Kong’s Pearl River Delta has the world’s second-highest volume of freight shipments and the number of dolphins there has declined as much as 80 percent over the past 15 years. The construction of a new runway for Hong Kong’s international airport and a new bridge have also contributed to fewer sightings of the threatened species.

But the coronavirus pandemic has given the dolphins a bit of a respite. Travel restrictions led to the suspension of high-speed ferry service and it appears the dolphins have begun to return to the delta in larger numbers.

Whether increased sightings mean their numbers are rebounding is unclear. More likely, researchers say, the marine mammals feel freer to use parts of their preferred territory.

The dolphins are by no means out of the woods. Conservationists hope to get the ferries rerouted when service resumes, and pollution, development and boats that take tourists out to see the dolphins are just some of the things that threaten their existence near Hong Kong.

But in the meantime, there are more pink dolphins hanging around Hong Kong.