- Salmo thymallus Linnaeus, 1758
Grayling, European grayling
IUCN: LC; Be (III); EUHD (V); RDBUkr: Вразливі; RDBUkrCarp: NT
Value of species
A similar species, T. baicalensis, has been introduced to Czechia and Slovakia in 1959. It first established a breeding population, but later disappeared around 1975, reportedly as a result of hybridisation with the local T. thymallus. Reported genetic variability suggests that at least the Adriatic and Loire populations are distinct lineages, but diagnostic morphological data are not yet available. Because of extensive stocking throughout the northern Adriatic basin it might be too late to investigate the original morphology, variability, genetics, and distribution.
Barents Sea basin west of River Ob, White, Caspian, Black, Baltic, White and North Sea basins, Atlantic westward to Loire drainage; Rhône drainage. Introduced in Po and Soca drainages, and over most of southern and central Finland.
Submontane reaches of rivers with a hard sand or stone bottom and well oxygenated, cold and fast-flowing water. In Scandinavia, in clear lakes and semi-anadromous in freshened part of northern Baltic basin. Usually in hollows behind boulders and shaded water under overhanging vegetation. Spawns in shallow stretches (usually 20-40 cm deep) or riffles, with moderate current (about 0.5 m/s) and clean gravel bottom.
Spawns for the first time at 2-3 years, females usually one year later than males, in northern Europe later than in central Europe. Spawns in early spring, usually in March-April, later in north, when temperatures reach 4-8°C, with a peak at full moon. Adults make short spawning migrations. Lacustrine populations often spawn in lake tributaries. Males start to defend small territories at spawning site in late morning and spawning usually starts in early afternoon at highest daily temperature. Females deposit eggs into substrate. Eggs hatch usually in 10-40 days. Alevins remain in gravel until yolk sack is absorbed (4-10 days). Feeding larvae live 3-4 weeks in open water below surface. Juveniles are benthic, in fast-flowing waters. Feeds predominantly on drifting invertebrates and terrestrial insects.
- Соколов Н.Ю. Каталог колекції круглоротих і риб Державного природознавчого музею НАН України // Наукові записки Державного природознавчого музею. – Львів, 2004. – Т.19. – С. 15-28.