GUANGZHOU-- There are now 2,060 endangered Chinese white dolphins living near an estuary of the Pearl River, marine authorities said Wednesday.

A Chinese white dolphin monitoring expedition in 2015 found that the population had increased from the 1,500 recorded in 2011, said He Shaoqing, deputy chief of Guangdong provincial maritime and fishery bureau.

The bureau issued a release on Wednesday on the marine environment of the province for 2015, which coincided with World Oceans Day.

He said the dolphin monitoring team had recorded 378 dolphin groups totalling 2,416, 2,060 were Chinese white dolphins.

Chinese white dolphins, which are a first-class protected animal, are found along a few coastal areas in the country.

The dolphins have a low reproduction rate and high habitat requirements. Female dolphins only give birth every three years, and the calves have only a 20 percent chance of survival, according to experts.

He said the ocean water quality near the coast of Guangdong Province is "basically good" but he warned excessive pollutants from five drainage rivers, of 12 in total, have been detected.

"Pollution control is still challenging," he said.