Photo/Illutration The Kujaku keyari seaweed (Provided by Shinsuke Ui)

KUSHIMOTO, Wakayama Prefecture--Seaweed that glows mysteriously when it is illuminated has become a popular must-see attraction among divers off the coast here. 

Now, a research team has discovered that the mysterious seaweed, which had been thought to be found only in Hawaii, has made its way into Japanese waters.

However, it remains unknown how the algae made the long journey over the several thousand kilometers from Hawaiian waters. 

A team led by Hiroshi Kawai, a specially appointed professor of phycology at Kobe University, studied the seaweed, which belongs to the brown algae group. 

The team will present the results of the study at a conference of the Japanese Society of Phycology that will be held online starting on March 20. The event will be organized by Hokkaido University.

What looks like fluffy hair grows from the top of the seaweed’s stems, which resemble the branches of a tree. The seaweed can grow to a height of 30 centimeters.

Sightings have been a topic of conversation among divers in the town from a dozen or so years ago.

The research team started its study using a sample of the seaweed that was collected in the sea off the coast of Kushimoto town at a depth of 15 meters in August.

The team also collected the seaweed in the same area of the sea at a depth of 24 meters in early March and studied in detail the characteristics of its shape and genes.

The researchers found that it is a close cousin to the seaweed called keyari (Sporochnus), which had been found in Japanese waters but is classified into different categories.

They found that there has been no formal report of the distribution of the seaweed in Japan and that it has long been regarded as algae unique to Hawaiian seas.

What looks like tied hair at the top of the stems beautifully glows when it’s illuminated as if they were a male peacock's feathers.

For this reason, the team named the seaweed “Kujaku keyari” (peacock keyari)

The team believes that the beautiful color is produced by “structural coloration,” the mechanism in which microscopic structure of surfaces produces color, and not by pigments.

Butterflies and jewel beetles also look colored because of structural coloration.

The team will continue with the study as it believes that the seaweed may be found in other Japanese waters. 

“We want to find out what advantage shining beautifully brings to the seaweed," Kawai said. 

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