A golden apple snail lays pink eggs. Originally from South America, the golden apple snail was named one of the 100 worst invasive species globally by the Global Invasive Species Database. The rapidly reproducing snail poses a threat to ecosystems around the world. Photo: IC Photo

Golden apple snail eggs collected by workers sit piled up Thursday in Nandianchi National Wetland Park, where staff members are trying to limit the species’ reproduction. Photo: Zhang Ruixue/Caixin

A cluster of golden apple snail eggs clings to a stone. The snails often lay eggs on rocks, bridges, roots and other solid surfaces above water. Photo: Zhang Ruixue/ Caixin

Clusters of pink eggs are attached to the bottom of a bridge at the wetland park. Each female golden apple snail can lay up to 50,000 eggs a year, mostly in the summer and autumn. Photo: Zhang Ruixue/Caixin

A cluster of pink eggs are attached to the leaves of a pickerelweed plant. The number of eggs at the park is particularly high this year, according to reports on Yunnan TV. Photo: Zhang Ruixue/ Caixin

A worker cleans the grass beside the river, removing the snail eggs in the process. Photo: Zhang Ruixue/ Caixin

Snail eggs stick to a tree trunk. Golden apple snails were first introduced to China in the early 1980s for food, and have since spread to most parts of southern China. Photo: Zhang Ruixue/ Caixin

A cluster of pink eggs floats on the water. Photo: Zhang Ruixue/ Caixin

Clusters of pink eggs hang from a boat at the park Thursday. Photo: Zhang Ruixue/Caixin

A sign saying “Cherish the wetland and protect Dianchi Lake” stands at the Nandianchi National Wetland Park on Thursday. Photo: Zhang Ruixue/ Caixin