Japanese sunfish are hard-working gonad chompers

[Taro Toporific]

lazy-sunfish.gif

Lazy sunfish are actually active predators
ScienceNews.org / 2015-May-01
If you spot an ocean sunfish (Mola mola) near the surface of the water, you might be amazed by its size...they can grow as large as 1,000 kilograms. You may also think the fish are nothing but lazy sunbathers. And that wouldn’t be an unreasonable guess — scientists used to think sunfish only drifted about in surface currents.
Then some researchers attached accelerometers to the fish and discovered they were active swimmers that could reach depths of 800 meters. But what were they doing in the deep?
To find out, Itsumi Nakamura and colleagues at the University of Tokyo attached instruments to seven sunfish caught in Funakoshi Bay on the east coast of Japan that could record the fish’s behavior and internal temperature...
...Over four to six days of recording, each fish traveled tens of kilometers; these were no lazy drifters. At night, they stuck close to the surface, within the top 20 meters of water. But during the day, the fish spent about 40 percent of their time in the top five meters of ocean and the rest diving to depths of up to 200 meters.
The cameras revealed that the sunfish were chasing after a variety of jellyfish and jellyfish-like creatures, mostly siphonophores. But the fish didn’t necessarily eat all of these creatures. When one sunfish approached a jellyfish, it ate only the gonads and oral arms...more...