Roach
|
|
- For other uses, see Roach (disambiguation).
| Roach | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 | ||||||||||||||||
| Scientific classification | ||||||||||||||||
| ||||||||||||||||
| Binomial name | ||||||||||||||||
| Rutilus rutilus Linnaeus, 1758 |
The Roach (Rutilus rutilus, family Cyprinidae, plural also roach) is a small freshwater and brackish water fish native to most of Europe and western Asia. It is typically a small fish, reaching 35 cm long, rarely 45 cm, and weighing up to 1 kg, rarely 1.8 kg. It is very common and its flesh is often enjoyed as food.
- Name's origin: from Old French roche, possibly from Germanic.
- Linnaean nomenclature (scientific name): Rutilus rutilus.
- Description: It has an elongated tailfin with silver scales.
- Habitat: Often found in moving water, the roach likes depths of about 2 or 3 m; it also enjoys weedy waters.
- Behaviour: a gregarious fish that lives in schools; the bigger ones keep themselves somewhat apart from the others.
- Food: small molluscs, insect larvae, worms, moss, algae, surface insects.
- Reproduction: from April to June or July when the water's temperature is at least 12°C, the female lays from 50,000 to 100,000 eggs. Roach grow slowly over a span of 2 or 3 years.
| Contents |
Introduction
The roach is a chordate, a teleostean, and an osteichthyan. In the vernacular, it is a bony fish. It is classified as a chordate for its notochord, which although absent in the adult fish, can be seen during its embryonic development. It is also a vertebrate, having a spinal column, and it also has a bony or cartilaginous skull, as well as a layered epidermis. The roach is a good example of chordates adapting to a watery environment, with high buoyancy, low O² content, and floating food.
The roach's characteristics
Protection
The roach has a non-keratinous outer skin of several layers about 100 μm thick. It is made up of connective cells. This epidermis has no glands, but there are glandular cells which secrete a mucus that protects the fish's scales. The scales themselves are bony, sheathing the roach in a kind of exoskeleton.
Senses
The roach has a head with eyes, and blind (ie without an opening at one end) nostrils, which do not open into the mouth as is true of other fishes. The roach also has a lateral line along each side, running from one end of its body to the other. This line of special scales is equipped with holes which connect the fish's outer body to the nervous system, enabling it to detect movements nearby by picking up small variations in long wavelengths in the water, caused by movements of other creatures.
Locomotion
The roach has a rather streamlined shape, being four times as long as it is wide. Two kinds of fins can be noted:
- unmatched fins, including the dorsal and caudal fins;
- matched fins, forming symmetrical pairs, including the pelvic fins at the rear and the pectoral fins farther forward.
The former give the fish stability in the water, and the latter are used for orientation.
Bodily systems
Respiratory apparatus
The roach has four pairs of gills set side by side that have hairs whose function is to keep foreign particles out. The gills together form a V-shaped set. There are also the gill slits which are used as exchange surfaces to extract oxygen from the water.
Circulatory apparatus
The heart is found beside the gills, which allows blood to be pumped through the gills with a considerable pressure. The circulatory system is otherwise rather simple. Deoxygenated blood passes through the heart only once.
External links
- Fishbase (http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=272&genusname=Rutilus&speciesname=rutilus) on roach
- Roach fact sheet (http://www.caspianenvironment.org/biodb/eng/fishes/Rutilus%20rutilus%20caspicus/main.htm), about subspecies Rutilus rutilus caspicus
- "Rutilus rutilus." ITIS Standard Report. (Integrated Taxonomic Information System: National Museum of Natural History, Washington, D.C., 2004-06-03). ITIS 163761 (http://www.itis.usda.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=163761)
- Brief guide to fishing for Roach (http://www.anglerstimes.co.uk/fishroach.htm)da:Skalle
de:Rotaugen fr:Gardon (poisson) lt:Kuoja nl:Blankvoorn fi:Särki sv:Mört