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Rare, newly hatched ghost shark found in trawling survey

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Rare, newly hatched ghost shark found in trawling survey

Sun, 15/05/2022 - 06:16
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A newly hatched ghost shark has been discovered near New Zealand’s South Island.

Newly-hatched deepwater ghost shark (Hydrolagus sp). Photo by Brit Finucci
Newly-hatched deepwater ghost shark (Hydrolagus sp). Photo by Brit Finucci

A neonate (newly hatched) ghost shark was found in the net during a trawling survey at about 1,200 metres below sea level. The survey had been conducted by NIWA to estimate the population of blue grenadier (hoki fish) at the Chatham Rise, off New Zealand’s South Island.

Its body was translucent and gelatinous, and it had two giant eyes on its pointed head—with a belly full of egg yolk. "You can tell this ghost shark recently hatched because it has a full belly of egg yolk," said Brit Finucci, a fisheries scientist from National Institute of Water and Atmospheric Research (NIWA).

"It's quite astonishing. Most deep-water ghost sharks are known adult specimens; neonates are infrequently reported, so we know very little about them," he added. 

Ghost sharks are also known as chimaeras, rat fish, spook fish or rabbitfish. They are a deep-sea cartilaginous species closely related to sharks and rays. Despite having existed for hundreds of millions of years, there are currently only 52 known species of ghost sharks.

Image
Hydrolagus sp
Chimaera at Manning Seamount. Image courtesy of the Mountains in the Sea Research Team; the IFE Crew; and NOAA.

Their embryos are found in egg capsules laid on the sea floor. They remain inside the capsules feeding off a yolk until it is time to hatch. Previous studies have shown that juveniles and adults have different dietary and habitat requirements. 

The NIWA researchers will use genetic tests to find out which species the ghost shark they had caught belong to. Then, they will compare it to an adult of the same species, to learn how the shark's characteristics, colour, size and dietary habits evolve over the shark’s lifetime. 

"Finding this ghost shark will help us better understand the biology and ecology of this mysterious group of deep-water fish,” said Finucci.

Sources
NIWA, Smithsonian Magazine
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