Press Release

February 24, 2012

Incorporated Administrative Agency, Fisheries Research Agency

World’s first discovery of ephyrae of giant jellyfish in the waters of China
? A step forward for advanced bloom forecast of the giant jellyfish ?

  • Commissioned survey on the distribution of the giant jellyfish in the waters of China was conducted by the East China Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences in May 2011.
  • Five ephyrae of about 2 mm in bell diameter were found firstly in the sea areas near the mouth of the Yangtze River and off the shore of Jiangsu.

The Fisheries Research Agency commissioned the East China Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences to survey the distribution of the giant jellyfish (Nemopilema nomurai) in the exclusive economic zone of China in the East China and Yellow Seas as part of the subsidized project of the Fisheries Agency entitled “International Collaborative Research Project of Giant Jellyfish Bloom”, in which the Bureau of Fisheries of the Ministry of Agriculture of China and the Chinese Academy of Fishery Sciences are cooperating. In the surveys conducted in May 2011, five ephyrae (bell diameter: about 2 mm) of N. nomurai were found in the sea areas near the mouth of the Yangtze River and off the shore of Jiangsu. Larger medusae of about 1 cm have been found in Liaodong Bay and off the western shore of Gunsan, Korea, but this was the first discovery of ephyrae as small as 2 mm. Based on their morphological development, the five ephyrae were estimated to have been released from polyps*1 10?15 days before their capture.

The discovery provides a reference base for estimating the reproduction area of the giant jellyfish and subsequent migratory routes by using ocean dynamical models and is expected to contribute to the development of advanced technologies for predicting the bloom of the giant jellyfish along the coast of Japan.


*1: Early developmental stage of the giant jellyfish. The polyp is sessile, living at the bottom of the sea, propagates asexually and releases ephyrae. Therefore, the area where the polyp lives is considered to be the reproduction area of the giant jellyfish.


ephyra of giant jellyfish (Nemopilema nomurai)