''Trachidermus fasciatus'' is a

species In biology, a species is the basic unit of 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 the appropriate s ...

of fish in the superfamily

Cottoidea A sculpin is a type of fish that belongs to the superfamily Cottoidea in the order Scorpaeniformes.Kane, E. A. and T. E. Higham. (2012)Life in the flow lane: differences in pectoral fin morphology suggest transitions in station-holding demand a ...

, the sculpins, and the only member of the

monotypic genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

''Trachidermus''. Its common name is roughskin sculpin.Froese, R. and D. Pauly. (Eds.
''Trachidermus fasciatus''.
FishBase. 2011. It has also been called four-gilled perch.Wang, D. and X. Wang
A study on hydrological and hydraulic features of ''Trachidermus fasciatus'' migration.
In: ''Advances in Water Resources and Hydraulic Engineering'' (pp. 562-67). Springer Berlin Heidelberg. 2009. It is native to the coastlines of China, Japan, and

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

, where it occurs at the mouths of rivers.

Description

This species is up to about long and weighs up to . It has a large, spineless head with a wide mouth and small eyes near the tip of the snout. The upper jaw is slightly projecting. The dorsal fin has 8 spines and 19 to 20 soft rays and the anal fin has no spines but 17 to 18 soft rays. This fish lacks

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number w ...

but its body surface is textured with knobbles. The gill opening is large and each

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

has two orange stripes. This fish lives in rivers,

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...

, and coastal ocean waters. It is

catadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...

; adults

spawn Spawn or spawning may refer to: * Spawn (biology), the eggs and sperm of aquatic animals Arts, entertainment, and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** '' Spawn: ...

on mudflats at the river mouths, and after hatching, the juveniles swim upstream to freshwater river habitat.Islam, M., et al. (2007)
Distribution and diet of the roughskin sculpin, ''Trachidermus fasciatus'', larvae and juveniles in the Chikugo River estuary, Ariake Bay, Japan.
''Ichthyological Research'' 54(2), 160-67.

Breeding

The female often lays eggs in empty

bivalve shell A bivalve shell is part of the body, the exoskeleton or shell, of a bivalve mollusk. In life, the shell of this class of mollusks is composed of two hinged parts or ''valves''. Bivalves are very common in essentially all aquatic locales, includi ...

s. Nests have been noted in the shells of the

oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not ...

'' Crassostrea rivularis'' and the

clam Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two shel ...

Atrina pectinata ''Atrina pectinata'' is a species of bivalves belonging to the family Pinnidae. The species is found in the Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence ...

''. It will also use other readily available structures for nesting, such as concrete blocks, lengths of

bamboo Bamboos are a diverse group of evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family. The origin of the word "bamboo" is uncertain, ...

, or

glass bottle A glass bottle is a bottle made from glass. Glass bottles can vary in size considerably, but are most commonly found in sizes ranging between about 200 millilitres and 1.5 litres. Common uses for glass bottles include food condiments, soda, liq ...

s. The male often guards the nest.Onikura, N., et al. (2002)
Spawning grounds and nests of ''Trachidermus fasciatus'' (Cottidae) in the Kashima and Shiota estuaries system facing Ariake Bay, Japan.
''Ichthyological Research'' 49(2), 198-201. The eggs are reddish-yellowTakeshita, N., et al. (1997)
Embryonic, larval and juvenile development of the roughskin sculpin, ''Trachidermus fasciatus'' (Scorpaeniformes: Cottidae).
''Ichthyological Research'' 44(2-3), 257-66. to

tangerine The tangerine is a type of citrus fruit that is orange in color. Its scientific name varies. It has been treated as a separate species under the name ''Citrus tangerina'' or ''Citrus'' × ''tangerina'', or treated as a variety of ''Citrus retic ...

in color, about in width, and sticky in texture, adhering to the shell or other nest material. The larval fish is about long at hatching.

Feeding

This species is a bottom-dwelling fish and is a

predator Predation is a biological interaction where 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 th ...

. The adult feeds on small fish and shrimps. The juveniles feed on

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

, such as rotifers. In the

Ariake Sea The is a body of salt water surrounded by Fukuoka, Saga, Nagasaki, and Kumamoto Prefectures, all of which lie on the island of Kyūshū in Japan. It is the largest bay in Kyūshū. Its deepest point is only about 50 meters (165 ft) deep, and ext ...

of Japan the juveniles show a clear preference for the

calanoid Calanoida is an order of copepods, a group of arthropods commonly found as zooplankton. The order includes around 46 families with about 1800 species of both marine and freshwater copepods between them. Description Calanoids can be distinguish ...

copepod species '' Sinocalanus sinensis''. Juveniles have been reared in the laboratory on diets of midge larvae, water fleas, and the

brine shrimp ''Artemia'' is a genus of aquatic crustaceans also known as brine shrimp. It is the only genus in the family Artemiidae. The first historical record of the existence of ''Artemia'' dates back to the first half of the 10th century AD from Urmia L ...

Artemia salina ''Artemia salina'' is a species of brine shrimp – aquatic crustaceans that are more closely related to '' Triops'' and cladocerans than to true shrimp. It belongs to a lineage that does not appear to have changed much in . ''A. salina'' is na ...

''.

Status

The habitat of the fish is degraded in some areas, particularly the river mouths of coastal China.

Pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

from rapid urban development, overfishing, and the construction of

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

s and

dikes Dyke (UK) or dike (US) may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), a subvertical sheet-like intrusion of magma or sediment * Dike (mythology), ''Dikē'', the Greek goddess of moral justice * Dikes ...

threaten the species in this region. Changes in the hydrology of the area, mainly from dams, are most concerning because they prevent the migration of the fish in the river systems.

References

{{Taxonbar, from=Q1852775 Cottinae Fish described in 1837 Monotypic fish genera Fish of Asia