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Squalius keadicus
Conservation status
	; Endangered (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Cyprinidae
Genus:	Squalius
Species:	S. keadicus
Binomial name
	Squalius keadicus; (Stephanidis, 1971)
Synonyms
	Leuciscus (Telestes) souffia ssp. keadicus Stephanidis, 1971; Leuciscus keadicus Stephanidis, 1971

Squalius keadicus is a species of fresh-water fish in the family Cyprinidae. It is found only in Greece, and known as the menida in Greek.

It is endemic to the Evrotas drainage and the Vassilopotamos stream in the southern Peloponnese.^[2]

Taxonomy

Phylogenetic studies on Leuciscinae^[3]^[4] provide evidence about the uniqueness of S. keadicus as an element of the ancient ichthyofauna and one of the most ancestral Leuciscus s. l.^[1] taxa of Greece, and perhaps of Europe.

Description

Body laterally compressed with dark brownish-blue colouration. D III/8, A III/8–9 (10), C 19, P I/13–15, V/II 7–9, Ll. 44–51, L. transverse 9–10/3–4, gill rakers 7–9, vertebrae 38–42, mouth subterminal.^[5]^[6] Maximum body length: the species grows up to 25 cm (9.8 in) TL,^[7] but more recently the longest specimen found had 15 cm (5.9 in) SL.^[8] Sexual dimorphism: males are smaller in size and with rather bigger pectoral and pelvic fins than females.^[9]

Habitat

According to Crivelli, S. keadicus prefers habitats with slow current.^[10] Barbieri et al however reported the species as energetic and strongly rheophilic,^[1] living in open sites of the river, on stony bottoms with a fast flow and relatively cool water. It feeds throughout the water column, principally on aquatic insects.^[11] The strongly rheophilic behaviour confines the species to river sections of increased flow, an area which is estimated to be far less than 10 km² (3.9 sq mi).

Reproduction

It matures in the second year of life (males possibly mature in the first). The breeding season is generally restricted in mid-spring. The species produces adhesive yellowish eggs, about 2 mm (3⁄32 in) in diameter from which unpigmented embryos, about 5.1 mm (3⁄16 in) TL, hatch out.^[11]

Conservation

It is threatened by habitat loss. The major threat is summer drought and concomitant water over-abstraction that lead to habitat degradation and loss. In the last decade, all tributaries and a large portion of the river dry up completely during summer. In addition, pollution from the local agricultural industries degrades water quality, especially during dry periods, leading to sudden mass mortalities. One of the possible consequences of the population decline is the reduction of the species’ genetic diversity that imposes a serious threat per se, as it lowers its ability to cope with adverse environmental changes.^[12] In the past, S. keadicus was abundant along its entire distribution area.^[9] In recent years, the population size in Evrotas has dramatically reduced.^[1] Moreover, the Vassilopotamos population is possibly extinct. It is protected by Presidential Decree No. 67/1981 of the Greek State.

Notes

^ Squalius was formerly a subgenus of Leuciscus

References

^ ^a ^b ^c Crivelli, A.J. (2006). "Squalius keadicus". IUCN Red List of Threatened Species. 2006: e.T60738A12402522. doi:10.2305/IUCN.UK.2006.RLTS.T60738A12402522.en. Retrieved 16 November 2021.
^ Economidis P.S. (1996). Société Française d'Ichtyologie (ed.). "Leuciscus keadicus (Cyprinidae), a valid species from River Evrotas (Greece)". Cybium. 20 (3): 303–309. doi:10.26028/cybium/1996-203-006.
^ Tsingenopoulos, C. & Karakousis, Y., 1996, Phylogenetic relationships of Leuciscus keadicus, an endemic cyprinid species from Greece, with other Greek species in the genus Leuciscus., Folia Zoologica, 45, p. 87-93
^ Ignacio Doadrio & José A. Carmona (1998) "Genetic divergence in Greek populations of the genus Leuciscus and its evolutionary and biogeographical implications" J. Fish Biol 53, p. 591–613
^ Stephanidis (1971) "Poissons d'eau douce du Péloponnèse" Biol. Gallo-Hel. 3(2) 163-172
^ Economidis, 1996
^ Ladiges & Vogt (1979) "Die Süsswasserfische Europas". Paul Parey (ed.), Hamburg. 299 pp
^ R. Barbieri; A.N. Economou; M.Th. Stoumboudi & P.S. Economidis (2002). M.J. Collares-Pereira; I.G. Cowx & M.M. Coelho (eds.). "Freshwater fishes of Peloponnese (Greece): distribution, ecology and threats". Conservation of Freshwater Fishes: Options for the Future Fishing News Books. Oxford: Blackwell Science: 55–64.
^ ^a ^b Stephanidis, 1971
^ A.J. Crivelli (1996) "The freshwater fish endemic to the Mediterranean region. An action plan for their conservation" Tour du Valat Publication Arles, France 171
^ ^a ^b Barbieri et al. 2002
^ Tsingenopoulos & Karakousis, 1996