A Nomura's jellyfish floats off Japan
's Nagasaki Prefecture in August 2005.
Relatively little is known about Nomura's jellyfish, so Shin-ichi Uye, a professor at Hiroshima University
, and colleagues across Japan have been studying the giant jellyfish in the lab to learn more about their habits and reproductive strategies.
The scientists are still not sure why thousands of the creatures appear off the Japanese coast in some years but not others.
"It is possible that they have a 'rest stage' or hibernation period in their development over several years, but then their numbers shoot up given certain environmental stimuli," Uye said.
Photograph courtesy Shin-ichi Uye, Hiroshima University