Now Is the Time to See Squid That Glow Like Fireflies

http://www.nytimes.com/2016/04/27/science/firefly-squid-toyama-japan.html

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Hop on a fishing boat in Toyama Bay, Japan, in the wee hours of the morning and you may feel as if you’re in a spaceship, navigating through the stars. That’s because each year, between March and June, millions of firefly squid transform the water into a galactic landscape. Lucky for you, all you need is a reservation to come aboard, your eyes and perhaps a really good camera.

The firefly squid may bring to mind a lightning bug. But the cephalopod is three inches long and flies through the sea, not the sky. And instead of a single light on its belly, it has five around each eye, three each on the tips of two of its arms and even more covering its body.

The firefly squid creates light via a chemical reaction inside its body, the same way a lightning bug does. The process involves wrangling together the dynamic duo of bioluminescence, two substances called luciferin and luciferase. Luciferin sits around waiting for luciferase, an enzyme that triggers luciferin to do what it does best — make light.

Up close, each squid looks like its own constellation of green and blue stars. Together, they form a bright blue nebula of bioluminescence, which is quite clear when the squid emerge from 1,200 feet during the spring to spawn. Firefly squid only live for a year. After making babies, they die.

Why the firefly squid glows is not precisely known. Theories range from attracting mates to deterring predators, but aren’t totally convincing. They also appear to lack the ability to regulate their flashes in synchronous patterns like some fireflies. Katsunori Teranishi, who studies the squid’s bioluminescence at Mie University in Japan, has found that the firefly squid constantly emits a weak light with no apparent advantage. But sometimes the light shines stronger, like a flashlight, from the squid’s arms. This might scare off nearby predators, but it could also attract those further away.

“The light cannot actively attract a mate, communicate with a mate, and deter a predator,” Dr. Teranishi said. When pressed for his own hypothesis for why the squid emits light, he suggested we ask the squids themselves.

The best time to observe firefly squid is in April, in Toyama City, Namerikawa and Uozu City, said Osamu Inamura, director of the Uozu Aquarium in Uozu City (where you can find firefly squid in captivity). This year tour boats depart from the Port of Namerikawa every morning at 3 a.m. from March 20 through May 8. You can catch the squid live at the only museum dedicated to them: Hotaruika Museum, also in Namerikawa.

If you happen to make it to Toyama Bay this year, appreciate the fact that the firefly squid is the only squid thought to have color vision. Here’s looking at you, squid.