Thymallus Thymallus.
Species description.
Thymallus Thymallus or European grayling as it is known has the nickname lady of the stream and is a wide spread species in Europe. Its easily recognised by its large dorsal fin that can be red blue or grey. It has silver sides with black spots and a yellow red or grey tail. With a maximum length of 60cm and a weight of 6.5KG its a medium sized salmonid. Large fish sometimes feed on a small fish but this species mostly feeds on aquatic insects and other insects. Its a cold-water lover and is found in deep pools with a bit less flow. Thymallus Thymallus has multiple different lineages which spread across Europe and Russia. The six recognised lineages are northern alps (Danube), southern alps (Danube), western Balkan (Danube), mixed central Europe (Rhone, Rhine, Elbe and some rivers flowing into the Baltic Sea), Scandinavian (Scandinavia) and north-eastern Europe (rivers flowing into the Caspian Sea).
Behaviour.
Grayling are found in deep slow flowing pools and its outflow and are mostly found near the bottom of the river. They feed larva, aquatic insects, bugs, ants and other insects, when the conditions are right, they also feed on the surface. They can be recognised by their calm movement and position in the river. And in colder times they tend to school together.
History.
Throughout history grayling have inhabited large parts of Europe but humans started to kill these beautiful fish because it was thought they competed with trout for food and they would keep trout out of some parts of the streams. Recent findings are that they feed on different items and they inhabit different micro habitats than trout. Some research even found that streams with good grayling populations have better trout populations as well.
Threats.
Grayling populations in a lot of its habitat are declining and under pressure. Declining water quality and an earlier end to the snow melt period might be some of the causes to this decline. This together with dams splitting populations, habitat destruction and there might be other things that play a roll as well.
Distribution.
The European grayling is a very wide spread species with populations in Austria, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, England, Finland, France, Germany, Hungary, Kosovo, Lithuania, Luxembourg, Macedonia, Moldavia, Montenegro, The Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Sweden, Switzerland and Wales.