Researchers in Japan have concluded that a surge in the number of giant jellyfish off the Japanese coast is a result of a hydropower dam in China.

The Mainichi Daily News reported that researchers from Japan’s National Institute for Environmental Studies have suggested that construction of the Three Gorges Dam in China, the world’s largest hydropower dam, is responsible for the explosion of the jellyfish population. The jellyfish have a negative effect on the Japanese fishing industry.

Nomura jellyfish, typically found in Japan, measure up to one meter in diameter and can weigh as much as 200 kilograms.

One of the breeding areas for the jellyfish is near the mouth of the Yangtze River, near Shanghai. Construction of the dam is thought to have reduced the production of silicon, which is necessary for the breeding of phytoplankton, the newspaper said.

Researchers plan to examine the relationship between the dam construction and the jellyfish over the next three years.