Toscana stream chub (Squalius lucumonis)

Also known as: brook chub
Synonyms: Leuciscus lucumontis
GenusSqualius (1)
SizeLength: 16 cm (2)

The Toscana stream chub is classified as Endangered (EN) on the IUCN Red List (1).

The Toscana stream chub (Squalius lucumonis) is a moderately sized fish that is endemic to Italy. The scales are yellowish, with a row of black pigment along one margin, and there is a golden, iridescent stripe running along the length of the body (2) (3). The grey fins of the Toscana stream chub become slightly orange in colour during the spawning season. The iris is light, with a brownish crescent-shaped area in the upper half (3).

The Toscana stream chub is endemic to the Tibern, Arno, Ombrone and Serchio river drainage basins of central Italy (1) (4).

The typical habitat of the Toscana stream chub is small to medium-sized warm freshwater streams and brooks, although it is occasionally found in main river courses (2) (3). During summer, this species may be confined to small pools within its range (1).

The Toscana stream chub’s spawning season runs from April to June (3), when eggs are laid in shallow, fast-flowing, warm water bodies (2). 

This species’ diet consists mainly of invertebrates, including molluscs, insects and crustaceans as well as detritus. The Toscana stream chub lacks teeth, and instead has two enlarged bones in the throat which grind together to break down food (2) (5)

The Toscana stream chub can live for up to five years in optimal conditions (1) (3).

Occurring in just 10 to 12 isolated populations, the Toscana stream chub has an extremely fragmented distribution within its restricted range (1) (3). Each of these populations is under threat from habitat change due to water extraction and pollution, to which this species is extremely sensitive. Throughout its range, the Toscana stream chub is forced to compete with introduced species such as the south European nase (Protochondrostoma genei) for resources such as food and spawning areas (1) (2) (3).

The Toscana stream chub is listed on Annex II of the EU Habitats Directive (6) and Appendix III of the Bern Convention (7), both of which provide guidelines for the conservation of European flora and fauna (1).

Limiting the introduction of non-native species, and restoration and protection of its habitat may help to conserve this endangered fish (3).

 Find out more about the Toscana stream chub and its conservation:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (October, 2011)
  2. FishBase - Squalius lucumonis (October, 2011)
  3. Bianco, P.G. and Katmaier, V. (2003) Threatened fishes of the world: Leuciscus lucumonis. Environmental Biology of Fishes, 68: 370.
  4. Manaresi, S., Mantovani, B. and Zaccanti, F. (1997) Comparison of isozymic and muscle protein in three taxa of Leuciscus from northern Italy. Italian Journal of Zoology, 64(3): 215-220.
  5. Campbell, A. and Dawes, J. (2004) Encyclopedia of Underwater Life. Oxford University Press, Oxford.
  6. EU Habitats Directive (January, 2012)
  7. Council of Europe: Bern Convention (January, 2012)