Grayling Biology, Life cycle and habitat
The Grayling (Thymallus thymallus)
Family: Salmonidae
Genus: Thymallus
Species: thymallus
British rod caught record: 4 lb 3 oz (1.82 kg), River Frome, Dorset, 1989
Grayling habitat
Range (Great Britain)
Indigenous and fairly common throughout most of England and Wales and Central Scotland.
Habitat
Prefers cool, well oxygenated water and thrives in moderately fast flowing streams and rivers, typically those below hills. It is non-migratory and is occasionally found in lakes.
Biology
Spawning takes place in spring. Large yellow eggs measuring 3.5 mm in diameter are deposited on sand and gravel in running water. After fertilisation they are covered with sand and they remain covered until they hatch three or four weeks later. Larvae disperse from spawning area several weeks later and they mature in two to five years when they are 20 to 30cm in length. Grayling are almost entirely carnivorous, the main part of the diet consisting of invertebrates. Eggs of their own and other species also eaten and larger specimens take fry and small fish.
Identification
Has a dark grey back, greyish green or pinkish sides and a white belly. Several longitudinal violet stripes run along the sides and the scales. There is an adipose fin but the most obvious characteristic is the dorsal fin which is very deep and long.