The roach, or rutilus roach (''Rutilus rutilus''), also known as the common roach, is a fresh- and brackish-water fish 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 ...

Cyprinid Cyprinidae is a Family (biology), family of freshwater fish commonly called the carp or minnow family, including the carps, the true minnows, and their relatives the barb (fish), barbs and barbel (fish), barbels, among others. Cyprinidae is the ...

ae, native to most of Europe and western Asia. Fish called roach can be any

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 the

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

Rutilus ''Rutilus'', commonly known as roaches, is a genus of freshwater ray-finned fish belonging to the family Leuciscidae, which includes the daces, Eurasian minnows and related fishes. This genus is a widely distributed lineage of leuciscids and r ...

'', '' Leucos'' and ''

Hesperoleucus ''Hesperoleucus'' is a genus of freshwater Actinopterygii, ray-finned fish belonging to the Family (biology), family Leuciscidae, which includes the daces, chubs, Phoxinus, Eurasian minnows and related species. The species in this genus are found ...

'', depending on locality. The plural of the term is also roach.

Description

The roach is a small fish, often reaching no more than about ; maximum length is . Its body has a bluish-silvery colour and becomes white at the belly. The fins are red. The number of scales along the lateral line is 39–48. The dorsal and anal fins have 12–14 rays. Young specimens have a slender build; older specimens acquire a higher and broader body shape. The roach can often be recognized by the big red spot in the iris above and beside the

pupil The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black becau ...

. Colours of the eye and fins can be very pale, however, in some environments. In Central and Northern Europe, the common roach can most easily be confused with the common rudd (''Scardinius erythropthalmus''), the dace (''Leuciscus leuciscus''), or the ide (''Leuciscus idus''). They can be distinguished by these characteristics: *The common rudd has a more yellow/greenish or golden colour. The backfin is placed more backwards and between the tip of the ventral scales and the first ray of the anal fin are only one or two scales. The roach has four or five scales there. The mouth of the rudd is more upturned and the head appears sharper. *The dace has a greenish body, colorless eyes and fins, and a distinct 'nose'. *The ide has a higher number of scales along its lateral line (55–61), a rounder body, and a bigger mouth and head.

Distribution

The common roach is found throughout Europe except for the area around the Mediterranean, and its distribution reaches eastward into Siberia. Eastern Europe and Asia have several subspecies, some with an oceangoing life cycle living around the Caspian and Black Seas. Around the Mediterranean and in northwestern parts of Spain and Portugal, several closely related species occur with no overlap in their distribution. It was introduced in Australia in the

Murray River The Murray River (in South Australia: River Murray; Ngarrindjeri language, Ngarrindjeri: ''Millewa'', Yorta Yorta language, Yorta Yorta: ''Dhungala'' or ''Tongala'') is a river in Southeastern Australia. It is List of rivers of Australia, Aust ...

and coastal drainages of southern

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

and Victoria from Europe during the 1860s and 1880s for sport purposes.

Ecology

The common roach is very adaptable and can be found in any

freshwater ecosystem Freshwater ecosystems are a subset of Earth's aquatic ecosystems that include the biological communities inhabiting freshwater waterbodies such as lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ec ...

, ranging from small ponds to the largest rivers and lakes. It feeds at any depth, although its preferred food sources tend to be in shallower water. It tolerates organic pollution and is one of the last species to disappear in polluted waters; it is also often the most numerous cyprinid in nutrient-poor waters. It also tolerates brackish water. Roach survive in temperatures from close to freezing up to around . In most parts of its distribution, it is the most numerous fish, but it can be surpassed by the

common bream The common bream (''Abramis brama''), also known as the freshwater bream, bream, bronze bream, carp bream or sweaty bream, is a European species of freshwater fish in the family Leuciscidae. It is now considered to be the monotypic, only speci ...

in biomass in water bodies with high

turbidity Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of both water clarity and wa ...

and sparse vegetation. The roach is a shoaling fish and is not very migratory with the exception of the oceangoing subspecies. In the cold season, they migrate to feed in deeper waters, whereas they prefer to feed near the surface during warmer weather. Roach mostly inhabit freshwater ecosystems that are somewhat vegetated, because larval and young fish are protected by the vegetation and the mature fish can use it for food. The common roach eats a wide range of foods, from plant material, bottom-dwelling (

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

) invertebrates, to worms and maggots. Young fish feed mainly on plankton, until they are of a size to use a wider diet. Roach can adapt to environments where invertebrates are scarce by slowing their growth, maintaining slender body shapes, and maturing early. Roach may live for 15 years or more. Roach are known to be parasitised by '' Rhipidocotyle campanula'' ( fluke), Myxobolus muelleri (myxozoa) and '' Raphidascaris acus'' (

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

Reproduction

The spawning season is generally from March to June, with some variation due to spawning being triggered by the rising of water temperature during spring and summer. Roach generally spawn at the same location each year. Large males form leks, which females enter. Males trail the females and fertilize their eggs. Their behaviour is rough and the fish often jump out of the water. A female can lay up to 100,000 eggs. When the pH of the water is below 5.5, the roach cannot reproduce successfully.

References

External links