Animal release activities are conducted by registered organizations, religious organizations, companies and individuals in Guangdong, Zhang said, adding his association arranges animal releases for government-funded projects to grow aquatic populations and other projects.

The country lacks a law regarding such releases, he said.

The Buddhist Association of China issued a message on its website in July, calling on followers to abide by laws on animal protection and free animals in a scientific, caring and correct ritualistic way.

Animal releases in China date back to the Spring and Autumn Period (770-476 BC) and proliferated after Buddhism came to the country, according to the association.

"The social and ecological environments are highly different from those in ancient times. If not conducted properly, animal freeing may go against the benevolent wish of Buddhism and even lead to greater harm to animals and the environment," said the association’s message.

In this commercialized age, frequent and massive animal releases have created a market and industry of capturing wild animals for freeing, which causes some deaths of those animals, it said.

The Beijing Water Authority and Beijing Municipal Bureau of Agriculture jointly issued a notice in August 2013, which levied fines of up to 5,000 yuan ($815) on those found illegally freeing animals.

He Xiaotong contributed to this story.