First Biofluorescent Fish Found in the Arctic

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Liparis gibbus specimen glows under flourescent lighting. A juvenile Liparis gibbus imaged under white light (top) and under fluorescent lighting (bottom) conditions.
© J. Sparks, D. Gruber, P. Kragh

It’s been found in loads of fishes, in marine turtles, and even in platypuses, opossums, flying squirrels, and springhares. Biofluorescence—the ability to absorb energy from sunlight and reemit it as a different color—tends to be most prominent in animals that live in tropical habitats. Now, Museum researchers have documented biofluorescence in an Arctic fish species for the first time.

The red-and-green glowing snailfish was identified during dives among iceberg habitats off the coast of eastern Greenland during a 2019 Constantine S. Niarchos Expedition.

“Overall, we found marine fluorescence to be quite rare in the Arctic, in both invertebrate and vertebrate lineages,” said John Sparks, a curator in the Museum’s Department of Ichthyology and one of the authors of the study, published this week in the American Museum Novitates. “So we were surprised to find these juvenile snailfish brightly fluorescing in not just one, but two different colors, which is very unusual in a single species.”

Sparks and colleague David Gruber, a research associate at the Museum and a biology professor at Baruch College, previously identified more than 180 new species of fishes that biofluoresce. Although this ability is now well documented in tropical fishes that live in regions where there is an even amount of daylight year-round, it was unknown how prolonged periods of darkness in the Arctic might affect fish biofluorescence.

In Greenland, Sparks and Gruber found very little marine fluorescence, even among groups of fishes that glow brightly in tropical and temperate regions. But there was an exception: two juvenile specimens of variegated snailfish (Liparis gibbus), the first species shown to biofluoresce in the Arctic.

“Finding a red and green biofluorescent snailfish on a dive among icebergs at night felt like a moment straight from The Life Aquatic with Steve Zissou,” Gruber said. 

In addition, the authors report red biofluorescence from an adult kelp snailfish (L. tunicatus) collected in the Bering Strait off of Little Diomede Island, Alaska, which was scanned by colleagues at NOAA Fisheries Service.

In the seven years since Sparks and Gruber first reported widespread biofluorescence in fishes, it has been found in a number of new lineages, but its exact function remains a mystery.

“We are now focusing our efforts on determining the function of fluorescence in various fish groups, including catsharks, where we have shown that bright green fluorescence enhances contrast in their pigmentation pattern, making it easier for individuals to see each other at depth,” Sparks said.