The Japanese white crucian carp, also known as Japanese carp, white crucian carp, or gengoro-buna (''Carassius cuvieri''), is a species of freshwater

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

in the carp

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 ...

(family Cyprinidae). It is found in Japan and, as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

, in several other countries in

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

. This fish is closely related to the commonly known

goldfish The goldfish (''Carassius auratus'') is a freshwater fish in the family Cyprinidae of order Cypriniformes. It is commonly kept as a pet in indoor aquariums, and is one of the most popular aquarium fish. Goldfish released into the wild have bec ...

Description

This is a medium fish, growing up to 50 cm, with a broad head and a blunt snout. The lips are fleshy, and lacking

barbels In fish anatomy and turtle anatomy, a barbel is a slender, whiskerlike sensory organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the zebrafish, the black dragonfish and some s ...

. The body is deep and laterally compressed, with a distinctly humped back. The scales are large and

cycloid In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another cu ...

in shape, with a complete lateral line. Serration is present on the last ray of the

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

and anal fins, and the

caudal 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 ...

is forked.

Taxonomy

The Japanese white crucian carp was formerly considered a subspecies of wild goldfish, and was classified as ''C. auratus cuvieri''. It has now been elevated to

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 ...

rank, however some authors are in disagreement. Genetic studies using mitochondrial DNA indicate that this species diverged from the ancestral form approximately one million years ago, during the early

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

. The original wild species unique to

Lake Biwa is the largest freshwater lake in Japan, located entirely within Shiga Prefecture (west-central Honshu), northeast of the former capital city of Kyoto. Lake Biwa is an ancient lake, over 4 million years old. It is estimated to be the 13th ol ...

is called . Fossil

pharyngeal teeth Pharyngeal teeth are teeth in the pharyngeal arch of the throat of cyprinids, suckers, and a number of other fish species otherwise lacking teeth.

Distribution and habitat

Historically, the Japanese white crucian carp was endemic to

, as well as the connected

Yodo River The , also called the Seta River (瀬田川 ''Seta-gawa'') and the Uji River (宇治川 ''Uji-gawa'') at portions of its route, is the principal river in Osaka Prefecture on Honshu, Japan. The source of the river is Lake Biwa in Shiga Prefectur ...

system, in Japan. However, it has been introduced to

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

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 ...

. In South Korea initial introductions were the result of stocking by government agencies. Subsequently, the species has also been spread through the

Buddhist Buddhism ( , ), also known as Buddha Dharma and Dharmavinaya (), is an Indian religion or philosophical tradition based on teachings attributed to the Buddha. It originated in northern India as a -movement in the 5th century BCE, and ...

practice of "life releasing", in which animals destined for slaughter are instead released into the wild. Possession of this species without a permit is prohibited in the state of

Vermont Vermont () is a state in the northeast New England region of the United States. Vermont is bordered by the states of Massachusetts to the south, New Hampshire to the east, and New York to the west, and the Canadian province of Quebec to ...

. It is a freshwater fish, preferring still or slow moving waters, and occurs at depths up to 20 meters. Typical habitats include lakes, canals, and backwaters.

Feeding, diet, and related information

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

species, Japanese white crucian carp feed on a variety foods, including algae, phytoplankton,

macrophytes Aquatic plants are plants that have adapted to living in aquatic environments ( saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

, and

invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordat ...

, such as

insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...

and

crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...

. During the larval stage,

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 ...

comprise the primary food source. Upon reaching 1.8 cm the young fish form

schools A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsor ...

and move offshore to feed on phytoplankton. Phytoplankton remains the primary food source through adulthood. This is reflected in the unique structure of their

pharyngeal teeth Pharyngeal teeth are teeth in the pharyngeal arch of the throat of cyprinids, suckers, and a number of other fish species otherwise lacking teeth.

Reproduction

Spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...

occurs from April to June, and takes place in areas of

aquatic vegetation Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that g ...

, including reed beds. Some individuals will migrate into connected satellite water bodies in order to spawn. Larvae and juveniles tend to remain close to spawning areas.

Importance to humans

Japanese white crucian carp, as well as other crucian carp species, are the target of an established local fishing industry on Lake Biwa. It is being used as a substitute for the depleted stock of '' nigoro-buna'' in the preparation of the intense-smelling fermented local dish '' funazushi'' due to the ''nigoro-buna'''s falling numbers. A larger cultivated variant, with a taller body depth known as , was developed from the original species, cultured in the

Osaka is a designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the third most populous city in Japan, following Special wards of Tokyo and Yokohama. With a population of ...

area and now released in many areas of Japan for sport fishing. It is enjoyed for catch-and-release. It is a major carp species in

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

aquaculture, where it is raised for food. This species has been identified as an intermediate host of '' Clinostomum complanatum'', a

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

fluke capable of infecting humans.

Conservation status

The wild species in

is listed as an endangered species in the Japanese

Red Data Book The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biolog ...

.Search system of Japanese Red Data
Factors in its decline include

water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. ...

, invasive species, and overfishing.

References

Japanese white crucian carp The Japanese white crucian carp, also known as Japanese carp, white crucian carp, or gengoro-buna (''Carassius cuvieri''), is a species of freshwater fish in the carp family (family Cyprinidae). It is found in Japan and, as an introduced species, ...

Endemic fauna of Japan Freshwater fish of Japan Freshwater fish of Taiwan

{{Cyprininae-stub