Tench

:"For the submarine class, see Tench class submarine."

Taxobox
name = Tench

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status = LR/lc | status_system = IUCN2.3
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Cypriniformes
familia = Cyprinidae
genus = "Tinca"
genus_authority = Cuvier, 1816
species = "T. tinca"
binomial = "Tinca tinca"
binomial_authority = (Linnaeus, 1758)The tench or doctor fish ("Tinca tinca") is a freshwater and brackish water fish of the cyprinid family found throughout Eurasia from Western Europe including the British Isles east into Asia as far as the Ob and Yenisei Rivers. It is also found in Lake Baikal.FishBase_species|genus=Tinca|species=tinca|year=2007|month=5] It normally inhabits slow-moving freshwater habitats, particularly lakes and lowland rivers.B. Whitton (1982). "Rivers, Lakes and Marshes" p 163. Hodder & Staughton, London.]

Ecology

The tench is most often found in still waters with a clayey or muddy substrate and abundant vegetation.A. F. Magri MacMahon (1946). "Fishlore", pp 156-158. Pelican Books.] This species is rare in clear waters across stony ground, and is absent altogether from fast-flowing streams. It tolerates water with a low oxygen concentration,FishBase_species|genus=Tinca|species=tinca|year=2007|month=5] even being found in waters where the carp cannot survive.A. F. Magri MacMahon (1946). "Fishlore", pp 156-158. Pelican Books.]

Tench feed mostly at night on algae and benthic invertebrates of various kinds that they root up from the bottom.A. F. Magri MacMahon (1946). "Fishlore", pp 156-158. Pelican Books.]

Breeding takes place in shallow water usually among aquatic plants where the sticky green eggs can be deposited.FishBase_species|genus=Tinca|species=tinca|year=2007|month=5] Spawning usually occurs in summer,B. Whitton (1982). "Rivers, Lakes and Marshes" p 163. Hodder & Staughton, London.] and as many as three hundred thousand eggs may be produced.A. Lawrence Wells (date unknown). "Observer Book of Freshwater Fishes", pp 101-105. Frederick Warne & Co.] Growth is rapid, and fish may reach a weight of 0.11 kg (0.25 lb) within the first year.

Morphology

Tench have a stocky, carp-like shape, olive-green skin, darker above and almost golden below. The caudal fin is square in shape. The other fins are distinctly rounded in shape.A. F. Magri MacMahon (1946). "Fishlore", pp 156-158. Pelican Books.] The mouth is rather narrow and provided at each corner with a very small barbel. Maximum size is 70 cm, though most specimens are very much smaller.G. Sterba (1962). "Freshwater Fishes of the World" pp 249-250. Vista Books, London.] The eyes are small and red-orange in colour.FishBase_species|genus=Tinca|species=tinca|year=2007|month=5] Sexual dimorphism is weak, limited to the adult females having a more convex ventral profile when compared with males.G. Sterba (1962). "Freshwater Fishes of the World" pp 249-250. Vista Books, London.] Males may also possess a very thick and flattened outer ray to the ventral fins.Fact|date=May 2007

The tench has very small scales, which are deeply imbedded in a thick skin, making it as slippery as an eel. Folklore has it that this slime cured any sick fish that rubbed against it, and from this belief arose the name doctor fish.A. Lawrence Wells (date unknown). "Observer Book of Freshwater Fishes", pp 101-105. Frederick Warne & Co.]

Golden tench

An artificially-bred variety of tench called the golden tench or schlei is a popular ornamental fish for ponds. This form varies in colour from pale gold through to red, and some fish have have black or red spots on the flanks and fins. Though somewhat similar to the goldfish, because these fish have such small scales, the golden quality is rather different.A. Lawrence Wells (date unknown). "Observer Book of Freshwater Fishes", pp 101-105. Frederick Warne & Co.] This variety is said to have been originally bred in Silesia.Fact|date=May 2007

Economic significance

Tench are edible and considered to have a fine flavour, working well in recipes that would otherwise call for carp.A. F. Magri MacMahon (1946). "Fishlore", pp 156-158. Pelican Books.] They are an important target for coarse anglers and are also used as fodder for predatory species such as bass.FishBase_species|genus=Tinca|species=tinca|year=2007|month=5] Tench, particularly golden tench, are also kept as ornamental fish in ponds and less frequently aquaria.Dick Mills (2000). "Understanding Coldwater Fish", p 106. Interpet Publishing. ISBN 1-9030-9810-6]

Angling

Large tench may be found in gravel pits or deep, slow-moving waters with a clayey or silty bottom and lots of aquatic vegetation. They take a variety of baits but are "nibblers" and are difficult to hook. Fish over 1 kg (2 lb) in weight are very strong fighters when caught on a rod.A. Lawrence Wells (date unknown). "Observer Book of Freshwater Fishes", pp 101-103. Frederick Warne & Co.]

References