Rare glowing viper sharks caught in Taiwan

Mysterious viper sharks caught off the coast of Taitung

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Rare viper sharks caught in Taiwan. (Image from FRI)

Rare viper sharks caught in Taiwan. (Image from FRI)

TAIPEI (Taiwan News) -- Off the coast of of Taiwan's Taitung County, scientists captured a rare species of shark, which was later identified as the seldom seen viper shark (Trigonognathus kabeyai), reported UDN

During a survey of fish in the Taitung Sea, scientists from the Fisheries Research Institute (FRI) caught five specimens of the mysterious creature at a depth of 350 meters off the coast of Taitung County's Donghe Township. The elusive fish is only seen in waters off Japan, Hawaii and Taiwan.

According to the FRI, the viper shark was first identified caught in 1986 at a depth of 330 meters off the coast of Aichi Prefecture in Japan and the second specimen was caught off of Tokushima Prefecture in 1987.  University of Tokyo researchers Kenji Mochizuki and Fumio Ohe described the shark as a new species and genus in 1990. 

It generic name derives from the the Greek word trigonon (triangle) and gnathus (jaw), while its specific name pays homage to Hiromichi Kabeya, the captain of the Seiryo-Maru, the vessel which captured the first specimen. 


Two viper sharks. (Image from Fisheries Research Institute)

Previous specimens in Taiwan had been caught by trawling waters in eastern Taiwan's Donggang and Nanfangao.

This time around, FRI said that using a single layer of gill nets, five fish were caught ranging in length from 26.2 to 32.6 cm. One fish survived and an attempt was made to keep it alive by immersing it in sea water that was 10 degrees Celsius, however it only lived for one day.

FRI said that the teeth on this type of shark are very different from other sharks and are needle-like, resembling viper fangs, thus the origin of the English name - viper shark. The upper and lower jaws can be extended forward to help it seize its prey. 

The sharks are able to migrate vertically in the ocean during day and night. During the day, it prowls waters at a depth of 300 to 400 meters, while at night it goes to shallower waters at 150 meters in search of food. 

On their underside, the sharks have distinct markings which contain large numbers of light producing photophores. Other photophores can be found to a lesser extent in other parts of the shark as well. 

It is not yet known whether the glowing markings on the sharks are used for communication or attracting prey.