Spotlight: ‘Tis the Season … for Firefly Squid

Spring in the northern hemisphere brings an ocean marvel of bioluminescence to the shores of Japan … masses of hotaru-ika, glowing Firefly squid!

Toyama Bay, Japan

Firefly squid {Watasenia scintillans}, also called Sparkling Enope Squid, are deep sea cephalopods that sometimes come to the ocean’s surface to catch prey at night. And in a dazzling light display of blue light from March to June each year, adults rise to the surface en masse to spawn by releasing and fertilizing their eggs, and then they die … completing their circle of life.

Their bioluminescence happens within photophores, light-producing organs in their tentacles and around their eyes. The photophores contain luciferin, a molecule that emits light when it reacts with oxygen.

This fascinating ocean creature and its annual dazzling light show is so beloved in Japan there’s even a museum dedicated to it, the Hotaruika Museum on the shores of Toyama Bay.

Among humans, firefly squid are a prized delicacy, featured on sushi and sashimi menus. A journalist who travelled to Toyama Bay during Hotaruika spawning season noted:

“Delicious as the sushi was, nothing tasted as good as the bioluminescence looked. The deep electric blue of the squid was unlike any other shade I’d ever seen, including other forms of bioluminescent creatures …

… Seeing them alive is a reminder that even in the darkest pockets of the planet, there are glimmering stars waiting to be discovered.”

~ Adam H. Graham, BBC journalist

Fishers reel in firefly squid-Japan. Photo by Noriaki Sasaki/AFP/Getty Images