As she had more frequent contact with the volunteers, she developed a better understanding of the finless porpoise and realized that perhaps a lot of locals, like herself, had little knowledge of the animal. So, in 2018, she joined the association.

Since then, she has been working on the front line of ecological protection, traveling by boat on Dongting Lake and Xiangjiang River, a tributary of the Yangtze. She has participated in more than 350 field trips to tackle illegal fishing, more than 100 of which took place at night, saving not only finless porpoises, but also other wildlife species in the area.

Once, when Tan and a group of volunteers went patrolling Dongting Lake by boat, they noticed a set of large-scale illegal fish traps covering nearly 0.67 hectares of the lake. Such traps are designed to capture all aquatic animals passing through them and, as such, posed a serious ecological threat.

It was a particularly windy day. The patrol team members contacted the local fishery authorities, slowly approached the nets, and released more than 500 kilograms of fish of varied species. Rain started pouring down just before they were about to head to their next destination, and the team had to wait where they were, as it was unsafe for the small boat to move.