''Sebastes schlegelii'', also known as the Korean rockfish, northern black seaperch, black rockfish, and woo-reok (우럭) in Korean, is a

predatory Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the subfamily

Sebastinae Sebastinae is a subfamily of marine fish belonging to the Family (biology), family Scorpaenidae in the Order (biology), order Scorpaeniformes. Their common names include rockfishes, rock perches, ocean perches, sea perches, thornyheads, scorpion ...

, the rockfishes, part of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Scorpaenidae The Scorpaenidae (also known as scorpionfish) are a family (biology), family of mostly ocean, marine fish that includes many of the world's most venomous species. As their name suggests, scorpionfish have a type of "sting" in the form of sharp ...

It is found in the Northwest Pacific Ocean.

Taxonomy

''Sebastes schlegeli '' was first formally described in 1880 by the German

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

and

paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

Franz Martin Hilgendorf Franz Martin Hilgendorf (5 December 1839 – 5 July 1904) was a German zoologist and paleontologist. Hilgendorf's research on fossil snails from the Steinheim crater in the early 1860s became a palaeontological evidence for the theory of ...

with the type locality given as

Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...

and

Hakodate is a Cities of Japan, city and seaports of Japan, port located in Oshima Subprefecture, Hokkaido, Japan. It is the capital city of Oshima Subprefecture. As of January 31, 2024, the city had an estimated population of 239,813 with 138,807 househol ...

in Japan. Some authorities place this species in the subgenus ''Acutomentum'', of which it is the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. The specific name honours the German

ornithologist Ornithology, from Ancient Greek ὄρνις (''órnis''), meaning "bird", and -logy from λόγος (''lógos''), meaning "study", is a branch of zoology dedicated to the study of birds. Several aspects of ornithology differ from related discip ...

and

herpetologist Herpetology (from Ancient Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is a branch of zoology concerned with the study of amphibians (including frogs, salamanders, and caecilians (Gymnophiona)) and reptiles (in ...

Hermann Schlegel Hermann Schlegel (10 June 1804 – 17 January 1884) was a German ornithologist, herpetologist and ichthyologist. Early life and education Schlegel was born at Altenburg, the son of a brassfounder. His father collected butterflies, which stimulated ...

, who, cowrote ''Fauna Japonica'' with

Coenraad Jacob Temminck Coenraad Jacob Temminck (; 31 March 1778 – 30 January 1858) was a Dutch people, Dutch patrician, Zoology, zoologist and museum director. Biography Coenraad Jacob Temminck was born on 31 March 1778 in Amsterdam in the Dutch Republic. Fro ...

in which they reported this species as '' S. inermis''.

Distribution

The species is found in the Northwest Pacific Ocean, off China, the Korean Peninsula and Japan.

Description

''S. schlegelii'' are blackish with black pelvic, anal and caudal

fins A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foil (fluid mechanics), foils that produce lift (force), lift or thrust, or provide the ability to steer or stabilize motion while travelin ...

. The seaperch has a total of 8 weak head spines. It is black when young and turns a mottled gray on the sides with age, often nearing white. This species can vary greatly in size between bodies of water. They can live for up to 18 years, and older individuals are often much larger than average; the maximum recorded length is . The record is .

Reproduction

''S. schlegelii'' is ovoviviparous and breed via

internal fertilization Internal fertilization is the union of an egg and sperm cell during sexual reproduction inside the female body. Internal fertilization, unlike its counterpart, external fertilization, brings more control to the female with reproduction. For inte ...

, females storing sperm until the development of the eggs. The phases between the start of the process and the end are separated by several months. The majority of the young are reared in late winter to early spring. Females produce between 125,000 and 1,200,000 eggs every breeding season. However it has been noted that not all of the eggs are released every year. It has been occasionally observed that the female may absorb the eggs back into her system. Along with other close related ''

Sebastes ''Sebastes'' is a genus of marine ray-finned fish belonging to the subfamily Sebastinae part of the family Scorpaenidae, most of which have the common name of rockfish. A few are called ocean perch, sea perch or redfish instead. They are found ...

'' species in the Northwest Pacific Ocean, a duplicated copy of the ''

amh AMH may refer to: Geography *''Academia Mexicana de la Historia'', the national academy of history, in Mexico *Alaska Marine Highway, ferry services along the southern coast of Alaska and to Washington state *AMH, IATA airport code for Arba Minc ...

'' gene (called ''amhy'') is the master sex-determining gene for ''S. schlegelii''. ''In vitro'' experiments demonstrate that the overexpression of ''amhy'' causes female-to-male sex reversal in ''S. schlegelii''. Further research has suggested that the ''amhy'' duplication occurred in the ancestor of ''Sebastes'' rockfish but is not used for sex determination in all species.

Ecology

It is a

pelagic fish Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that live on or near the bottom, and reef fish that are associated with coral reefs. ...

, occurring on the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

. Like other pelagic fish, they spend most of their time amid the water columns and are generally associated with rougher terrain. Juveniles are often associated with rafts of seaweed. '' Lepeophtheirus elegans'' is a species of

sea lice Sea lice (singular: sea louse) are copepods (small crustaceans) of the family Caligidae within the order Siphonostomatoida. They are marine ectoparasites (external parasites) that feed on the mucus, epidermal tissue, and blood of host fish. Th ...

reported on ''S. schlegelii''.

Fishery

They make up an important component of nearshore fisheries in northern Asia. The preference of the species for rough terrain can make it somewhat inconvenient for

commercial fisheries Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often p ...

, which are often situated in nearshore, shallow water, and rocky areas (

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

s). The species is a popular quarry for recreational anglers.

References

schlegelii Fish of Japan Fish of Russia Fish of China Taxa named by Franz Martin Hilgendorf Fish of the Pacific Ocean Fish described in 1880 {{Scorpaeniformes-stub