TAIPEI (Taiwan News) — A group of fishermen was surprised to catch a strange-looking shark with big blue eyes, a black body and a tiny head compared to its two-meter-long body.

Many on the fishing boat, as well as in Taitung harbor, had no idea what sort of aquatic creature they had caught. Later, marine experts identified it as a deep-water shark listed as a "vulnerable" species facing a high risk of extinction due to overfishing and climate change, per PTS.

The weather off the coast of Taitung has been particularly good this week, with calm seas allowing fishermen to go further out to sea and return to port in the morning to unload the bountiful catch from their boats.

"I only know it's a shark, a bottom-dwelling shark, but I don't know what kind of shark it is," said fisherman Chen Ju-an (陳如安).

Researchers from the Eastern Marine Biology Research Center said it was a kitefin shark that lives at a depth of about 1,000 meters. This shark is distinctive due to its large liver, which allows it to adjust its buoyancy in the ocean.

"It is generally not aggressive towards humans. It is usually caught by longline fishing or nets that drag the bottom of the ocean. It’s different from other sharks as the liver accounts for a large proportion of its body, which it uses as a buoyancy tool," said Huang Yu-hsu (黃侑勖), an assistant fellow at the Eastern Marine Biology Research Center.

Marine biologists say the species is currently not a protected species in Taiwan but is overfished as fishermen prize its skin and the oil from its liver which is thought to have medicinal uses.