The black ghostshark (''Hydrolagus homonycteris''), also known as the black chimaera, is a

chimaera Chimaeras are cartilaginous fish in the order Chimaeriformes , known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae, or Siganidae, respectively. At ...

species within the family

Chimaeridae The Chimaeridae, or short-nosed chimaeras, are a family of cartilaginous fish. They resemble other chimaeras in general form and habits, but have short, rounded snouts, without the modifications found in related families. Many species have lon ...

. The species lives off the coasts of

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, in the southwestern Pacific Ocean, in depths of . It has a black or dark brown body; males have a total length of . The species is closely related to the abyssal ghostshark. Although it is sometimes caught as a bycatch, it does not have any major threats and is listed as least concern by the International Union for Conservation of Nature (IUCN).

Taxonomy and etymology

The black ghostshark was described by Dominique A. Didier in 2008. It is one of 23 species in the genus ''

Hydrolagus ''Hydrolagus'' is a genus of fish in the family Chimaeridae found in the Atlantic, Indian and Pacific Oceans.Weigmann, S. (2016)Annotated checklist of the living sharks, batoids and chimaeras (Chondrichthyes) of the world, with a focus on biogeog ...

''. Its genus name, ''Hydrolagus'', comes from the Greek words ''hydro'', which means "water" and ''lagos'', which means "hare". The specific name, ''homonycteris'', is composed of the word ''homo'', the Latin word for man, and ''nycteris'', the word for bat. Its name was taken after Thomas A. Griffiths, a professor at

Illinois Wesleyan University Illinois ( ) is a state in the Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolitan areas include, Peoria and Rockfor ...

, whose students called him "bat man".

Description

The black ghostshark can grow up to in body length, with a maximum total length of for males. Its body is dark in color, typically black or a dark shade of brown. Its eyes are large and its snout is slightly pointed. Its dorsal spine is large and it has round pelvic fins. Its claspers have areas of bristles on them and are somewhat short and thin. Its appearance is similar to that of the abyssal ghostshark, another species of chimaera to which it is closely related; however, the black ghostshark's dorsal spine is longer than that of the abyssal ghostshark and its claspers are darker and smaller.

Distribution and habitat

The black ghostshark lives in the southwestern Pacific Ocean off the coasts of south-eastern Australia, from

Portland, Victoria Portland is a city in Victoria, Australia, and is the oldest European settlement in the state. It is also the main urban centre in the Shire of Glenelg and is located on Portland Bay. As of the 2021 census the population was 10,016, increasing ...

, to

Ulladulla, New South Wales Ulladulla is a coastal town in New South Wales, Australia in the City of Shoalhaven local government area. It is on the Princes Highway about south of Sydney, halfway between Batemans Bay to the south and Nowra to the north. Ulladulla has close ...

, covering the states of New South Wales, Tasmania, and Victoria. The species also occurs in New Zealand from the West Norfolk Ridge to the

Campbell Plateau The Campbell Plateau is a large oceanic plateau south of New Zealand and the Chatham Rise. It originated in the Gondwanan breakup and is part of Zealandia, a largely submerged continent. The above sea level parts of the plateau — the Bounty ...

. In Australia, it lives in waters deep, while it lives at slightly shallower depths in New Zealand, at . The species is found at the continental slope and seamounts.

Threats and conservation

Throughout its New Zealand range, the black ghostshark is sometimes caught as a

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

; a study showed the number of specimens caught gradually increasing from 1990 to 2010. It is generally caught from trawls and fisheries, which operate in deeper waters in New Zealand. It is also recorded to be caught intentionally in the country, although what the species can be used for there is unknown. In June 2018 the New Zealand

Department of Conservation An environmental ministry is a national or subnational government agency politically responsible for the environment and/or natural resources. Various other names are commonly used to identify such agencies, such as Ministry of the Environment ...

classified the black ghostshark as "Not Threatened" with the qualifier "Secure Overseas" under the

New Zealand Threat Classification System The New Zealand Threat Classification System is used by the Department of Conservation to assess conservation priorities of species in New Zealand. The system was developed because the IUCN Red List, a similar conservation status system, had some ...

. In Australia, the species is also caught as a bycatch, but infrequently.

South Tasman Rise The South Tasman Rise is an area of seafloor that lies 550 km south of Hobart, Tasmania in the Southern Ocean where water depths are about 1,500 metres. The South Tasman Rise is also known as the Tasmania Ridge or South Tasmania Ridge. The So ...

Fishery, which was previously a threat to the species, closed in 2007, making the species less vulnerable in the Australian area. The species is safe to eat and has good quality flesh. At the current time, it does not have any major threats, so no conservation actions are taking place for the species and it is listed as

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

References

{{DEFAULTSORT:Black ghostshark

black ghostshark The black ghostshark (''Hydrolagus homonycteris''), also known as the black chimaera, is a chimaera species within the family Chimaeridae. The species lives off the coasts of Australia and New Zealand, in the southwestern Pacific Ocean, in depths ...

Marine fish of Southern Australia Marine fish of New Zealand Vertebrates of Tasmania Taxa named by Dominique A. Didier Dagit