Black ghostshark

9/10/2017

Hydrolagus homonycteris. Source: CSIRO National Fish Collection. License: Cc BY Attribution

The black ghostshark (Hydrolagus homonycteris) is a large (reaching up to 101 cm in length), uniformly dark brown to black coloured chimaera. Found off the continental slope and seamounts off south-eastern Australia between New South Wales, Victoria, Tasmania and Tasmania’s southern seamounts in 870-1450 metres (m), these deep sea chimaeras can also be seen off New Zealand waters, as deep as 500-1400 m.

They have highly deciduous skin, which can make ID-ing them a hassle. But as their common name says, they are darkly coloured. The black ghostshark has slender, short claspers, and pre-pelvic claspers, but lack an anal fin. Like some chimaeras, they have a large head and large eyes, accompanied by a medium-sized snout. According to reports, their eyes are a bluish-black colour and their teeth as dark too! I’m sensing a “I am the dark!” theme here.

While little else is known about these sharks, scientists do know that males mature at approximately 80 cm while females mature around 88 cm. The IUCN has currently assessed them as Least Concern (LC).

ever heard of the chimaera?

glossary

Anal fin: fins behind the anus; used for stability while swimming.
Claspers: Sexual reproduction organs found on male elasmobranchs and chimaeras.
Continental shelf: Extends from a continent underwater, resulting in a shallow-water area.
Continental slope: The steep slope from a continental shelf to the ocean floor; usually around 20 km (12.4 miles) wide and made up of mud and silt substrate. It is an ideal area for deep sea fishing.
Deciduous skin: the continuous, periodic or seasonal peeling of their scales/skin.
IUCN: International Union for Conservation of Nature.
Pre-pelvic claspers: closer to the head than pelvic claspers.
Seamount: mountain rising from the ocean seafloor that does not reach to the water's surface.