''Sebastes inermis'', the Japanese red seaperch or dark-banded rockfish, is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

belonging to the subfamily

Sebastinae Sebastinae is a subfamily of marine fish belonging to the family Scorpaenidae in the order Scorpaeniformes. Their common names include rockfishes, rock perches, ocean perches, sea perches, thornyheads, scorpionfishes, sea ruffes and rockcods. D ...

, the rockfishes, part of the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Scorpaenidae The Scorpaenidae (also known as scorpionfish) are a family of mostly 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 spines coated with venom ...

. It is found in the northwestern

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

Taxonomy

''Sebastes inermis'' was first formally described in 1829 by the French

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and ...

Georges Cuvier Jean Léopold Nicolas Frédéric, Baron Cuvier (; 23 August 1769 – 13 May 1832), known as Georges Cuvier, was a French naturalist and zoologist, sometimes referred to as the "founding father of paleontology". Cuvier was a major figure in na ...

with the

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

given as Japan. Together with '' S. ventricosus'' and '' S. cheni'' these three taxa form a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

and have been treated as a single species in the past. Some authorities place this species complex in the

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed betw ...

''Mebarus''. The specific name ''inermis'' means “unarmed”, a reference to the relatively small spines on the head.

Description

''Sebastes inermis'' has sharp lachrymal spines with the rest of the spines on the head are rather weak. The caudal fin is not strongly emarginate. It has a dark red or pale brown body on the back and flanks. The

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

s reach beyond the level of the anus when held down., The pectoral fins have 15 rays while the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as s ...

has 7 rays. This species grows to a total length of , and the heaviest recorded specimen weighed .

Distribution and habitat

''Sebastes inermis'' it occurs from southern

Hokkaido is Japan, Japan's Japanese archipelago, second largest island and comprises the largest and northernmost Prefectures of Japan, prefecture, making up its own List of regions of Japan, region. The Tsugaru Strait separates Hokkaidō from Honshu; th ...

southward to

Kyushu is the third-largest island of Japan's five main islands and the most southerly of the four largest islands ( i.e. excluding Okinawa). In the past, it has been known as , and . The historical regional name referred to Kyushu and its surroun ...

, Japan, and the southern part of the Korean Peninsula. It is a

demersal fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They o ...

with pelagic juveniles which live among floating mats of seaweeds.

Biology

''Sebastes inermis'' feeds on zooplankton. Males are territorial, establishing territories which range in area from . The male initiates courtship when a female approaches their territory and perform a lateral display with rushing and turning movements being recorded frequently as part of the courtship. The courtship behaviour lasts for around 30 minutes before copulation. It climaxes with the pair ascending into the water column, above the seabed, the male suddenly coils around the body of the female to copulate.

Human usage

''Sebastes inermis'' is one of the most important target species for fisheries in Japan and is also grown in aquaculture to supply market demand.

References

{{Authority control inermis Sport fish Fish of Korea Taxa named by Georges Cuvier Fish described in 1829