The First Successful Attempt to Reveal The Ecology of The Giant Jellyfish, and Contributing to Damage Prevention through The Creation of An Outbreak Forecasting System: Seeking to “Regenerate Rich Satoumi Environments” While Expanding Our Research on An International Level

He embraces jellyfish, the enemy of his beloved zooplankton, as new study animals. My goal is to listen to the voices of aggregated jellyfish and convey their messages to us human beings.

I began studying jellyfish after the Faculty of Applied Biological Science transferred from Fukuyama Campus to Higashi-Hiroshima Campus. Originally, my research focused on zooplankton, but after I attempted to collect plankton at new sampling locations, I found that the majority of the samples were affected by jellyfish, thus making them unsuitable for my experiments. Around that time, there was considerable talk among local fishermen about “detrimental effects of jellyfish outbreaks on fishing.” Therefore, I turned my research topic toward jellyfish, which is enemy of my former study animals, copepods.

In those days, there were only a few jellyfish researchers in the world, and jellyfish ecology was shrouded in mystery. It was against this backdrop that I sought to clarify the origins of the giant jellyfish (Nemopilema nomurai), their living conditions, and why they grew to such enormous sizes.

In fact, I became the first researcher in the world to successfully breed giant jellyfish, which subsequently went from being an unknown creature to one of the most well-known jellyfish species in the world. This was the key success of our research team.

Thereafter, further research on jellyfish blooms revealed that they are caused by warming, eutrophication, and reductions in fish stocks, all of which are attributable to human activities. In other words, as human activities flourish, jellyfish are gradually wielding their innate power and threatening human populations. In this regard, I see the jellyfish as a “messenger from the sea” that has come to inform humans of their arrogance.

 

Hiroshima University has played a leading role in establishing practical knowledge and understanding in the field of jellyfish research and outbreak forecasting among others areas of research.

arge blooms of the giant jellyfish have occurred almost annually since 2002, and in 2005, these outbreaks were estimated to have caused a damage of approximately 30 billion yen, due to the lack of effective countermeasures. Hence, we created the concept of “jellyfish bloom forecasting” to minimize the damage caused by these outbreaks. Based on the knowledge that jellyfish originate in Chinese waters and drift to the Sea of Japan within one to three months (with the help of the Tsushima current), our monitoring activities have enabled us to predict the scale of the jellyfish blooms.

Since 2006, our group at Hiroshima University has continued to examine the giant jellyfish in China’s exclusive economic zone by visually observing them from the deck of international ferries. Based on the results of these investigations, it is now possible to predict the occurrence of jellyfish blooms approximately one month before they intrude upon the Tsushima Strait. Although 2009 saw the largest invasion of jellyfish in Japan to date, the damage was reduced to 10 billion yen as a result of the forecasting system and the countermeasures taken by those involved.

As a researcher, I am extremely happy and proud that our research achievements have contributed to society in this way. In 2012, I had the extreme honor of receiving the “Commendation for Contribution to Promote the Country as a Marine Nation.”

 

The ultimate goal of jellyfish research is to contribute to “regenerating rich satoumi environments.”  I hope to expand our research at the international level together with leading researchers of the next generation.

In June 2013, the “Fourth International Jellyfish Bloom Symposium” was held in Hiroshima. The symposium was attended by as many as 140 scientists from 29 countries and it was the first time that the event had been held in East Asia – a region that has suffered tremendously from jellyfish blooms. During the proceedings, researchers focused on the worldwide growth of jellyfish blooms and presented a wide array of research findings, thus resulting in an extremely successful event.

One of the presentations introduced a study with an interesting methodology. This study focused on a Mediterranean resort in which outbreaks of poisonous jellyfish had damaged its tourism industry. The researchers enlisted the support of local residents, who used their mobile phones to report the presence of jellyfish and gather data on jellyfish incidences, which they made available for real-time viewing. Recently, the number of young jellyfish researchers has been increasing and information exchanges between researchers and local inhabitants has flourished. This will probably lead to the further widening of research on jellyfish blooms in the future.

While continuing to conduct visual observations from the ferry, we intend to increase the precision of our jellyfish outbreak forecasting system based on the successes of the last decade. In addition, we hope to make further efforts to return East Asia’s seas to their former glory as “rich satoumi environments” with abundant fish populations.

Finally, we endeavor to expand our research at the international level by sharing our knowledge of jellyfish bloom mechanisms and outbreak prediction technology-knowledge that our research team has developed up until now as a world leader in jellyfish research. This is not something that I intend to achieve myself, instead, it is a challenge that I hope young researchers will embrace. Therefore, it is my wish that young researchers will pursue their dreams through marine environment research, develop their English language skills-which can also be used outside the realm of science-and conduct collaborative research with like-minded researchers from overseas.

 

Profile

Biological Oceanography, Graduate School of Biosphere Science

22012-2013     Executive and Vice President (Peace/International)
2007-2011     Executive and Vice President (Education)
1995-1996     Visiting professor, Oregon State University
1994-     Professor, Graduate School of Biosphere Science, Hiroshima University
1983-1994     Associate Professor, Hiroshima University
1978-1983     Research Associate, Hiroshima University